Wikipedia:Featured article candidates/TRAPPIST-1/archive3

TRAPPIST-1

 * Nominator(s): Jo-Jo Eumerus (talk) 15:23, 5 June 2023 (UTC)

So, this has been at FAC twice before but maybe third time's the charm. This article is about a dim star that happens to host a system of 7 possibly Earth-like planets, two or three of which may have temperatures that allow the existence of liquid water. It's featured in science as a case study of habitability on planets around such low-mass stars, including the important question of whether such planets can host atmospheres. Jo-Jo Eumerus (talk) 15:23, 5 June 2023 (UTC)

Sandy Georgia

 * Comment: I have reviewed on talk and anticipate supporting once topic-area experts have been through. Sandy Georgia  (Talk)  15:54, 5 June 2023 (UTC)
 * Support. I reviewed on talk pre-FAC, have followed all commentary here on FAC, and am satisfied that reasonable commentary from topic experts since the FAC was initiated have been addressed.   Perhaps the excessively long commentary here can be moved elsewhere to allow for a clearer vision and to encourage review by others. Sandy Georgia  (Talk)  11:13, 3 July 2023 (UTC)

Comments by Nimbus 227
As an amateur astronomer and experienced Wikipedian I thought I should read through this, it's a long article so I didn't get very far but I noticed a couple of things that should be corrected for FA level text.
 * The first sentence of the lead describes the temperature with a surface temperature of about 2566 K. 'About' is an odd term to use when the temperature is given to an accuracy of 1°, the exact same temperature is repeated in the body text without 'about'. The temperature uses the abbreviation 'K' which is not explained, not everyone will know that it is Kelvin, it should be linked, explained or possibly better still left out so that only the familiar centigrade/Fahrenheit remain (and Kelvin is in the text for readers who want that level of detail).
 * Let's see if it now displays links and spell-out and rounds to a multiple of 10. Or do you recommend a different roundination? Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * Featured Articles with numbers in the lead often have them rounded to prevent readers' eyes glazing over, there is some guidance at MOS:LARGENUM, I would round the light year and parsec distances to 41 and 12.5, the precise distance being in the body text. Of course other editors come along and change it back because it's 'wrong'!!


 * The word 'transit' appears about 20 times but it is not explained or wikilinked, it should be linked to astronomical transit at the first instance (third paragraph in the 'Description' section) and possibly linked again later.
 * Added one link to begin with. Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * I will try to read further down this evening (UTC!), cheers. Nimbus (Cumulus nimbus floats by)  14:45, 6 June 2023 (UTC)


 * (Continued) Some terms are not wikilinked at first instance (or at all), exoplanet could be mentioned in the lead as that's what they are, orbital resonance and stellar eclipse.
 * Added links. Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * The list of planets seems to be disconnected from the planets section above by the atmosphere section, could the two tables be combined? Perhaps the section header levels need adjusting?
 * Hrmm. I think I deliberately wrote it that way because the question of atmospheres is really front and centre when we discuss the habitability of exoplanets around red dwarfs. That and I begin writing first about the planets as a whole and only later lead into discussing the specific planets. Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * 'As of 2020' appears a few times, have there been any discoveries in the last three years?
 * Yes, but not all of the "unsettled as of 2020" questions have had new answers. Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * Could the 'as of 2020s' be changed to 'as of 2023' so that the article appears to be up to date? Nimbus (Cumulus nimbus floats by)  17:00, 7 June 2023 (UTC)
 * I'd prefer not - sourcing a text "as of 2023" to a 2020 publication when there is no new information is a bit too much original research. I don't want to treat "absence of evidence" as "evidence of new evidence". Jo-Jo Eumerus (talk) 17:44, 7 June 2023 (UTC)
 * Footnote A is not cited (appears to be the only one).
 * I believe this falls under WP:CALC. Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * Referencing, have not looked at formatting or quality of sources, some facts are cited twice, looks unnecessary for uncontentious facts. Citations and footnotes appear mid-sentence which seems to be against WP:REFPUNCT.
 * That's going to be hard to fix - sometimes a sentence needs to stand on more than one source. Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * Might be worth asking one of the FA co-ords for advice on this. The effect is jarring while reading, perhaps that's why REFPUNCT was devised? Some of the sentences are quite short with only one fact stated but two citations. I like the footnote explanations, caters for the PDF version where blue links don't work. It is possible that an editor working on a potential FA sees this article's citations and copies the style. Nimbus (Cumulus nimbus floats by)  17:43, 7 June 2023 (UTC)
 * REFPUNCT was devised way back in the olden days when people placed citations before punctuation, and we even had scripts going around fixing them. Nowhere does any guideline say you can't place a citation mid-sentence, AFAIK. Sandy Georgia  (Talk)  18:27, 7 June 2023 (UTC)
 * The idea that references cannot be placed mid-sentence is a misreading of WP:REFPUNCT. That guideline tells us the citations are placed after punctuation, and says nothing about citation placement in instances where there is no puncutation, and it never says citations can't be placed mid-sentence (as in practice they often are). Sandy Georgia  (Talk)  18:26, 7 June 2023 (UTC)
 * The exoplanet navbox (Template:Exoplanet) does not contain a link to this article, strictly it could be removed per WP:BIDIRECTIONAL though I see its usefulness, the navbox is also used in the related planets articles with the same problem. Nimbus (Cumulus nimbus floats by)  18:30, 6 June 2023 (UTC)
 * Removed it. Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * The infobox links apparent magnitude six times and color index four times (WP:OVERLINK) and 'Luminosity (bolometric)' is not linked (the only parameter that's not linked), it could be linked to Luminosity. Template:Starbox character (and its related templates) coding should be revised. Nimbus (Cumulus nimbus floats by)  08:34, 7 June 2023 (UTC)


 * Jo-Jo ? Gog the Mild (talk) 17:50, 27 June 2023 (UTC)
 * That sounds like a problem with Template:Starbox character and not with this article, though? BTW, I already pinged the people who have commented so far, on their talk pages. Jo-Jo Eumerus (talk) 18:02, 27 June 2023 (UTC)
 * The problem is that readers and potential FA editors/nominators might not realise it is a template, they just see it as text on the page. Technically it is a problem in over 5,000 articles. Perhaps things have changed but FA nominators were encouraged to improve related articles and templates, a request at Template talk:Starbox begin would be pertinent. Nimbus (Cumulus nimbus floats by)  09:58, 3 July 2023 (UTC)
 * I've asked for a fix on the template's talk page, but since I doubt that it will happen quickly I've done a change on the article page, until the template is resolved. Jo-Jo Eumerus (talk) 10:44, 3 July 2023 (UTC)

Support by WereSpielChequers
I've kicked the tyres a few times on this one, and I think it is up to snuff. Hopefully it will need a lot of updating in the future as this is clearly at the leading edge of astronomy. More is to be discovered here, so it is good to have an article at this standard with our current level of knowledge.  Ϣere Spiel  Chequers  07:46, 26 July 2023 (UTC)
 * This is an important topic, thanks for your work on it. If found it an interesting read and not too impenetrable for someone who knows little of astronomy other than what one would expect of any hardcore Science Fiction fan. I have made some tweaks, hope you like them.
 * "and would, in many cases, appear larger than Earth's Moon in the sky of Earth"; Surely that would be "at closest approaches"? Most of the time these planets are going to be far further away than at their closest approach and sometimes will be on the other side of the star. Especially when we are comparing planets to each other rather than a planet to its moon.
 * Yes, it's just not spelled out like that in the source. Worth adding anyway? Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * I would think so, would it be possible to add a comparison to Venus at its closest approach?  Ϣere Spiel  Chequers  09:15, 3 July 2023 (UTC)
 * "Its mass is approximately 9% of that of the Sun,[27] being just sufficient to allow nuclear fusion to take place." and "With a radius 12% of that of the sun, it is only slightly larger than the planet Jupiter." these two statements in combination give the impression that Jupiter is only a little short of becoming a star. But there is a big gulf between Jupiter and TRAPPIST-1, a gulf bigger than a Brown Dwarf. My back of the envelope calculation shows that if TRAPPIST-1 had a few Jupiter masses less it would be a Brown Dwarf. So perhaps "just sufficient to allow fusion of hydrogen and only a few Jupiter sized masses heavier than a Brown Dwarf star". And with a radius more than 10% greater than Jupiter I think we can go with something stronger than only slightly larger, also it might be worth adding their respective masses, Jupiter's being around 1% that of TRAPPIST-1.
 * Mmm, this is where my background knowledge kicks in - star radius is extremely unrelated to star mass. I don't think 10% is a big radius difference, even if the mass difference is indeed substantial. And I don't like linking to Brown dwarf because that implicitly assumes that the mass cutoff is a fixed value, when in reality it depends on metallicity. Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * The lede says "Discovered in 2000, it is slightly larger than Jupiter and has a mass of about 9% of the Sun" I think that's what threw me - comparing it to Jupiter by volume but the sun by mass. I suspect a general reader would be as likely as me to get confused by that. May I suggest that in the lede you use mass for both comparisons.  Ϣere Spiel  Chequers  18:27, 2 July 2023 (UTC)
 * Went with a radius and mass thing instead, since folks will want to know the radius too. Jo-Jo Eumerus (talk) 20:14, 2 July 2023 (UTC)
 * Yes that's better. Thanks  Ϣere Spiel  Chequers  09:18, 3 July 2023 (UTC)
 * How about adding (though much more massive) after "only slightly larger than the planet Jupiter"?  Ϣere Spiel  Chequers  13:16, 25 July 2023 (UTC)
 * Added, but I don't like the lack of sourcing. Jo-Jo Eumerus (talk) 16:32, 25 July 2023 (UTC)
 * "Eventually the surfaces would cool until the magma oceans solidified, which may have taken between a few billions of years, or a few millions of years in the case of TRAPPIST-1b." As Trappist-1b is the closest to the star I would have thought it would have taken longest to cool?
 * Clarified with a small transposition. Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * OK I guess this means we are still at early days in this subject. That's quite a range.  Ϣere Spiel  Chequers  22:41, 25 June 2023 (UTC)
 * "Stellar wind-driven escape in the Solar System is largely independent on planetary properties such as mass" should that be "independent of" or is this some sort of astronomy jargon?
 * No, just a bad word choice; resolved it. Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * "the age of TRAPPIST-1 has been established at about 7.6±2.2 billion years" with such a wide margin of error I don't think we should use the word established.
 * I admit that I am not sure what other word to use here. Jo-Jo Eumerus (talk) 16:23, 7 June 2023 (UTC)
 * How about "TRAPPIST-1's age is estimated as 7.6±2.2 billion years" ? Sandy Georgia (Talk)  09:35, 8 June 2023 (UTC)
 * That works; it's in. Jo-Jo Eumerus (talk) 16:20, 8 June 2023 (UTC)
 * I like the use of estimate instead of established. Is this an unusually wide range for the possible age of a star, and if so should we say that? I'm thinking something more like "As of 2013 the age of Trappist-1 has not been precisely established, estimates range from a similar age as our sun to about twice that" and then put the figures.  Ϣere Spiel  Chequers  10:32, 13 June 2023 (UTC)
 * I am a bit concerned about OR with such a formulation; I don't think that this age range is unusually large. Jo-Jo Eumerus (talk) 17:42, 13 June 2023 (UTC)
 * Whether the range is large or not, 5.4 to 9.8 is not necesssarily that much greater than Sol, with that margin of error it is roughly one or two times the age of Sol.  Ϣere Spiel  Chequers  13:28, 25 July 2023 (UTC)
 * That still doesn't solve the source/OR issue. I've added the Solar System age. Jo-Jo Eumerus (talk) 16:32, 25 July 2023 (UTC)
 * That's all for now, but I enjoyed reading it and will likely be back for more  Ϣere Spiel  Chequers  18:14, 6 June 2023 (UTC)
 * "and their orbits have been constrained by measurements" would "calculated using" be more understandable to a general audience?  Ϣere Spiel  Chequers  13:16, 25 July 2023 (UTC)
 * Probably yes, so it's in. Jo-Jo Eumerus (talk) 16:32, 25 July 2023 (UTC)


 * Hi, this is in danger of timing out, so could I encourage you to revisit sooner rather than later? Thanks. Gog the Mild (talk) 17:30, 2 July 2023 (UTC)

Comment
Could the recent JWST result be incorporated into the article? SevenSpheres (talk) 17:12, 11 June 2023 (UTC)
 * In November-December it will. It's not practical to update such articles in real time, and it'd be premature most of the time. Jo-Jo Eumerus (talk) 18:03, 11 June 2023 (UTC)
 * I think that the "In November-December it will" needs some explanation, or reviewers may reasonably query whether it meets "it neglects no major facts or details and places the subject in context" and "it is a thorough and representative survey of the relevant literature". — Preceding unsigned comment added by Gog the Mild (talk • contribs)
 * I have some minor doubts about these two studies - they mostly disregard tidal heating and many leave the possibility of a very thin atmosphere open. So I'd prefer to see a bit more commentary on them, rather than immediate addition. Jo-Jo Eumerus (talk) 19:22, 30 July 2023 (UTC)
 * That seems reasonable to me. There is an obvious tension between the consensus of scholarly sources, which will take time to form, and "a thorough and representative survey of the relevant literature". Gog the Mild (talk) 19:30, 30 July 2023 (UTC)

Sandbh comments
Below I’ve listed the topic sentences of each paragraph of the article so that I can check its logical flow. My specific comments have been indented.

Lede

TRAPPIST-1 is a cold dwarf star in the constellation Aquarius, with a surface temperature of about 2,566 kelvins (2,290 degrees Celsius; 4,160 degrees Fahrenheit).


 * Is it not an "ultra-cool" red dwarf star?
 * Yes, but that's encompassed by "cold" without using a technical term. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * I was expecting to see how far away T1 is from us. Later in the article, in the List of Planets section, the planets are first referred to in terms of their distance from T1, and then their orbital period. Is there some reason why T1's distance from us is not first mentioned?
 * It's now mentioned. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)

The star has a planetary system of seven known exoplanets.


 * The dual use of "planet" strikes me as being not up to FAC prose standard.
 * I am minded to disagree; it's two different words with the same component. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * My objection remains. Sandbh (talk) 06:04, 5 July 2023 (UTC)
 * So do I - it's two words with different meaning, sharing only one string. Perhaps you have an alternative wording choice? Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)
 * This paragraph goes on to say, "…the discovery of two terrestrial planets in orbit around TRAPPIST-1. In 2017, further analysis of the original observations identified five more planets."


 * Are not all seven planets thought to be rocky i.e. terrestrial?
 * Yes, but here the repetition doesn't add anything. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * I was not looking for a repetition. Rather, if you specify that two of the planets are rocky it is courteous to the reader to clarify the status of the other fiven given they are mentioned in the same sentence. Sandbh (talk) 06:04, 5 July 2023 (UTC)
 * Courteus yes, but not sourceable, I'm afraid. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)
 * The last two sentences of this second paragraph of the lede start, "These seven planets…" and "The planets…". This kind of alliteration strikes me as being not up to FAC prose standard.
 * I am not sure that "bodies" would be better, as folks might think that it refers to additional bodies. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * My concern about not being up to FAC standard remains. Sandbh (talk) 06:04, 5 July 2023 (UTC)
 * Pulled it, but my concern about clarity remains and clarity is also a component of good writing. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

As many as four of the planets – designated d, e, f and g – orbit at distances where temperatures are suitable for the existence of liquid water, and are thus potentially hospitable to life.


 * General comment: What’s the novelty of T1? Is it because it has seven Earth-sized planets?
 * Jo-Jo Eumerus? Sandbh (talk) 06:04, 5 July 2023 (UTC)
 * First multiple terrestrial planets around a very cold star, with multiple ones in the habitable zone. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

Contents 1. Description 2. Planetary system 3. Potential planetary atmospheres 4. List of planets 5. Possible life 6. Research history and reception


 * It seems peculiar to discuss the planetary system in section 2 and have a table of the planets therein and to then have a section 4 called "List of planets", and another table of the planets therein. A better flow of contents could look like:


 * 1. Star
 * 2. Planets
 * 3. Habitability
 * 4. Research history and reception


 * You are not the first one to question this structure. However, I think there is an advantage to first discuss the planets as a whole, then a major aspect of their habitability and scientific interest, and then only delve into planet-specific details. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * My concern remains. Sandbh (talk) 06:04, 5 July 2023 (UTC)
 * Noted, but I find my structure better - besides, atmosphere needs a separate section altogether, given its sheer importance. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

Description
TRAPPIST-1 is in the constellation Aquarius,[15] five degrees south of the celestial equator.


 * The first two sentences start, “TRAPPIST-1 is…” and “TRAPPIST-1 is…”. This repetition is not up to FAC prose standard.
 * Fixed. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * The last sentence of this paragraph starts: "It has…" The next two sentences of the second para, read “It is…” and “Its…”. This repetition is not up to FAC prose standard.
 * Changed a bit, but I am not sure that there are many other ways to say this; ideas? Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * Alternate between "TRAPPIST-1" and "its". Sandbh (talk) 06:04, 5 July 2023 (UTC)
 * Took care of this, also elsewhere in the article. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

It is a red dwarf of spectral class M8.0±0.5,[e][25][26] making it a relatively small and cold star.
 * This now reads, "The star is a red dwarf of spectral class M8.0±0.5,[e][25][26] making it a relatively small and cold star." The repetition of "star" is not up to FAC prose standard. Sandbh (talk) 06:04, 5 July 2023 (UTC)


 * The penultimate sentence reads, “The star also emits Lyman-alpha radiation and X-rays,[34] but no detectable radio waves.[35]” The end of the third paragraph then says, “The star emits faint radiation at short wavelengths such as x-rays and UV radiation…”. Why the dual mention of X-rays?
 * Writing screw-up; I've remedied but maybe the wording can be improved. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * Why is the temperature of T1 mentioned in the topic sentence of the first paragraph of the lede but not in any of the topic sentences of this Description section?
 * Because I didn't see a source that could be used to write it in a temperature->spectral type->implications form. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * Delrez et al. 2022, p. 21. Sandbh (talk) 06:12, 5 July 2023 (UTC)
 * I see no such information there? Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

TRAPPIST-1 is cold enough for condensates to form in its photosphere[h]; these have been detected through the polarization they induce in its radiation during transits of its planets.

Rotation period and age

Measurements of TRAPPIST-1's rotation have yielded a period of 3.3 days; earlier measurements of 1.4 days appear to have been caused by changes in the distribution of starspots.


 * "Age" needs to be mentioned in the topic sentence.
 * I don't think you can do that without jerking the flow around by first mentioning rotation period and age, then rotation period, then returning to age? Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)

Activity
 * My concern remains. Sandbh (talk) 06:12, 5 July 2023 (UTC)
 * So does my objection. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

Numerous photospheric features have been detected on TRAPPIST-1.[50]


 * This paragraph includes the sentence, “The Kepler and Spitzer Space Telescopes have observed possible bright spots, which may be faculae,[j][52][53] although some of these may be too large to qualify as faculae.[54]” Such repetition is not up to FAC prose standard.
 * That was my thinking as well, but when it was written without the repetition folks thought that it wasn't clear. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * My concern remains. Sandbh (talk) 06:12, 5 July 2023 (UTC)
 * So does my objection. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

The star has a strong magnetic field[58] with a mean intensity of about 600 gauss.[l][60]

TRAPPIST-1 loses about 3×10−14 solar masses per year[62] to the stellar wind, a rate which is about 1.5 times that of the Sun.

Planetary system
TRAPPIST-1 is orbited by seven planets, designated TRAPPIST-1b, 1c, 1d, 1e, 1f, 1g, and 1h[65] in alphabetic order going out from the star.[o][68]

All of the planets are much closer to their star than Mercury is to the Sun,[73] making the TRAPPIST-1 system very compact.[74]

The inclinations of the orbits relative to the system's ecliptic are less than 0.1 degrees,[79] making TRAPPIST-1 the flattest planetary system in the NASA Exoplanet Archive.[80]

Size and composition

The radii of the planets are estimated to range between 75% and 150% of Earth's radius.[85]


 * The topic sentence needs to say something about composition.
 * Again, I don't think you can do this without jerking the flow around. Besides, isn't the header the topic sentence already? Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * My concern remains. Relying on the header is lazy prose, not up to FAC standard prose. Sandbh (talk) 06:34, 5 July 2023 (UTC)
 * So does my objection. And badly flowing sentences honestly are a bigger problem than relying on a header - introducing a section topic is the header's job! Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

The TRAPPIST-1 planets are expected to have compositions that resemble each other[87] as well as Earth.[88]


 * At 63 words, the second sentence is a too long, “The estimated densities of the planets are lower than Earth's[89] which may imply that their cores are smaller than that of Earth, that they have large amounts of volatile chemicals,[r] that their iron exists in an oxidised form rather than as a core,[91] that their cores includes large amounts of other elements,[92] or that they are rocky planets with less iron than Earth.”
 * I've split it up a bit, but it needs double checking. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * It still doesn't work, and now includes a spelling mistake. Sandbh (talk) 06:34, 5 July 2023 (UTC)
 * Don't see it, nor a better way to write, other than perhaps a bulleted list? Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

Resonance

The planets are in orbital resonances;[100] the durations of their orbits have ratios of 8:5, 5:3, 3:2, 3:2, 4:3 and 3:2 between neighbouring planet pairs,[101] and each set of three is in a Laplace resonance.[t][74]


 * Since the resonances are listed here why are they listed again in the "List of planets" section?
 * One's a table about planets, the other is prose. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)

The closeness of the planets to TRAPPIST-1 results in tidal interactions[107] stronger than those on Earth.[108]


 * Is this a resonance thing?
 * No. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * So why is that paragraph in this section? Sandbh (talk) 06:34, 5 July 2023 (UTC)
 * Changed the header. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)
 * This second paragraph has a too long 45 word sentence:
 * “The mutual interactions of the planets, however, could prevent them from reaching full synchronisation by forcing periodic or episodic full rotations of the planets' surfaces with respect to the star on timescales of several Earth years, which would have important implications for the planets' climates.[111]”
 * I think it can be split, just need some feedback if by topic (rotation vs climate) or by fact vs explanation and implications. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * That's up to you. Sandbh (talk) 06:34, 5 July 2023 (UTC)
 * Split done, and I repeat "interaction" because otherwise it's not clear what we are talking about. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

The resonances continually excite the eccentricities of the TRAPPIST-1 planets, preventing their orbits from becoming fully circular.

Tidal heating could influence temperatures of the night sides and cold areas where volatiles may be trapped, and gases are expected to accumulate; it would also influence the properties of any subsurface oceans[120] where volcanism and hydrothermal venting[x] could occur.[122]


 * Is this a resonance thing?
 * No. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * So why is it mentioned in this section? Sandbh (talk) 06:34, 5 July 2023 (UTC)
 * Why is tidal heating mentioned in paragraph 2 and again in paragraph 4?
 * To me it seems like it's mentioned in paragraphs 3 and 4? Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * That's right. So why is tidal heating mentioned in this section? Sandbh (talk) 06:34, 5 July 2023 (UTC)
 * Answered above, I think. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

Skies and impact of stellar light

Because most of TRAPPIST-1's radiation is in the infrared region, there may be very little visible light on the planets' surfaces; Amaury Triaud, one of the system's co-discoverers, said the skies would never be brighter than Earth's sky at sunset[130] and only a little brighter than a night with a full moon.


 * Does stellar light have an "impact"?
 * Yes, if by "impact" we mean "effects" which I think is a reasonable use. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)


 * I disagree. Sandbh (talk) 06:34, 5 July 2023 (UTC)
 * Do you have a better word, then? Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

Habitable zone

For a dim star like TRAPPIST-1, the habitable zone[z] is located closer to the star than for the Sun.[137]

Intense extreme ultraviolet (XUV) and X-ray radiation[148] can split water into its component parts of hydrogen and oxygen, and heat the upper atmosphere until they escape from the planet.


 * Relevance to habitability?
 * Indeed, as it's hard to have life without an atmosphere or water. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * Then its relevance should be explained. Sandbh (talk) 06:34, 5 July 2023 (UTC)

Moons

No moons with a size comparable to Earth's have been detected in the TRAPPIST-1 system,[152] and moons are unlikely in such a densely packed planetary system.


 * Doubling up: moons and moons. Not up to FAC prose standard.

Magnetic effects

The TRAPPIST-1 planets are expected to be within the Alfvén surface of their host star,[157] the area around the star within which any planet would directly magnetically interact with the corona of the star, possibly destabilising any atmosphere the planet has.[158]


 * Doubling up. Not up to FAC prose standard.
 * Fixed. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * Now it has three mentions of "star". Sandbh (talk) 06:34, 5 July 2023 (UTC)

Formation history

The TRAPPIST-1 planets most likely formed further from the star and migrated inwards,[163] although it is possible they formed in their current locations.[164]

The presence of additional bodies and planetesimals early in the system's history would have destabilised the TRAPPIST-1 resonance if the bodies were massive enough.[176]
 * Resonance with what?
 * Explained. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * Is US English in operation here? Stablized? Sandbh (talk) 06:34, 5 July 2023 (UTC)

Due to a combination of high insolation, the greenhouse effect of water vapour atmospheres and remnant heat from the process of planet assembly, the TRAPPIST-1 planets would likely initially have had molten surfaces.

Potential planetary atmospheres
As of 2020, there is no definitive evidence that any of the TRAPPIST-1 planets have an atmosphere,[ac][182] but atmospheres could be detected in the future.[183]


 * Doubling up. Not up to FAC prose standard.
 * Hmm. I see, but if I put in "they" might people think it refers to "planets"? Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)

The existence of atmospheres around TRAPPIST-1's planets depends on the balance between the amount of atmosphere initially present, its rate of evaporation, and the rate at which it is built back up by meteorite impacts,[74] incoming material from a protoplanetary disk,[188] and outgassing and volcanic activity.[189]

If the planets are tidally locked to TRAPPIST-1, surfaces that permanently face away from the star can cool sufficiently for any atmosphere to freeze out on the night side.[193]

Numerical modelling and observations constrain the properties of hypothetical atmospheres around TRAPPIST-1 planets:[163]


 * The topic sentence needs to say, in summary form, what the following six dot points say.
 * My concern remains. Sandbh (talk) 06:39, 5 July 2023 (UTC)
 * It does - "hypothetical atmospheres". Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

Theoretical modelling by Krissansen-Totton and Fortney (2022) suggests the inner planets most likely have, if any, oxygen-and-CO2-rich atmospheres.[213]

Stability

The emission of extreme ultraviolet (XUV) radiation by a star has an important influence on the stability of its planets' atmospheres, their composition and the habitability of their surfaces.[216]


 * Is this the case for T1?
 * Yes. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * So why not say so? Sandbh (talk) 06:39, 5 July 2023 (UTC)
 * Why specify? It's a general fact and this is an article about a star. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

TRAPPIST-1 is moderately to highly active,[25] and this may be an additional difficulty for the persistence of atmospheres and water on the planets:


 * Active in what sense? The topic sentence needs to say, in summary form, what the following three dot points say.
 * Put in an explanation. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)

The star's history also influences the atmospheres of its planets.[231]


 * In what way?
 * As explained in the following sentences. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * Laziness and not up to FAC prose standard. The rest of the paragraph is only about the impact of radiation, so why not flag this in the topic sentence? Sandbh (talk) 06:39, 5 July 2023 (UTC)
 * Because I don't think that is necessary right there. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

List of planets
TRAPPIST-1b has an average distance from its star of 0.0115 astronomical units (1,720,000 km)[233] and orbits same in 1.51 Earth days. It is expected to be tidally locked to the star.


 * What is its semi-major axis?
 * It's in the link? Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)

TRAPPIST-1c has a semi-major axis of 0.0158 AU (2,360,000 km)[233] and orbits its star every 2.42 Earth days.


 * Is it tidally locked?

TRAPPIST-1d has a semi-major axis of 0.022 AU (3,300,000 km) and an orbital period of 4.05 Earth days.


 * ditto

TRAPPIST-1e has a semi-major axis of 0.029 AU (4,300,000 km)[233] and orbits its star every 6.10 Earth days.[245]


 * ditto

TRAPPIST-1f has a semi-major axis of 0.038 AU (5,700,000 km)[233] and orbits its star every 9.21 Earth days.[245]


 * ditto

TRAPPIST-1g has a semi-major axis of 0.047 AU (7,000,000 km)[233] and orbits its star every 12.4 Earth days.[245]


 * ditto

TRAPPIST-1h has a semi-major axis of 0.062 astronomical units (9,300,000 km); it is the system's least massive known planet[233] and orbits its star every 18.9 Earth days.[245]


 * Which is the most massive?
 * We don't know for certain if any of the planets are tidally locked. As for most massive, probably TRAPPIST-1b but I think in this system we know more of minimum masses than maximum ones. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)


 * So why is tidal locking mentioned for 1b and 1c? As for mass, how is that surface gravity is known but not mass? Sandbh (talk) 06:43, 5 July 2023 (UTC)
 * Because it is more certain for these than for the more distant planets. Do you want to merge the tables? The other one contains the mass. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)
 * "For masses, ChatGPT advises as follows:


 * Based on the available data as of my knowledge cutoff in September 2021, here are the estimated masses of the planets in the TRAPPIST-1 system:


 * TRAPPIST-1b: Approximately 1.017 Earth masses
 * TRAPPIST-1c: Approximately 1.156 Earth masses
 * TRAPPIST-1d: Approximately 0.297 Earth masses
 * TRAPPIST-1e: Approximately 0.772 Earth masses
 * TRAPPIST-1f: Approximately 0.934 Earth masses
 * TRAPPIST-1g: Approximately 1.148 Earth masses
 * TRAPPIST-1h: Approximately 0.331 Earth masses


 * Please note that these mass estimates are subject to revision as new observations and improved techniques provide more accurate measurements. It is always recommended to refer to the latest scientific research for the most up-to-date information on the TRAPPIST-1 system." Sandbh (talk) 06:53, 5 July 2023 (UTC)

Possible life
Life may be possible in the TRAPPIST-1 system, and the star's planets are considered a promising target for its detection.[220]


 * Why is this content here, separated out from the Habitable zone subsection in the Planetary system section?
 * Because in the context of exoplanets, "habitable zone" specifically refers to surface temperature, which gets treated by itself. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)
 * My concern remains. Sandbh (talk) 06:44, 5 July 2023 (UTC)
 * And so does my reason, sorry. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)

Research history and reception
TRAPPIST-1 was discovered in 1999[ao] by astronomer John Gizis and colleagues[279] during a survey of Two Micron All-Sky Survey data for the identification of close-by ultra-cool dwarf stars.[280][282]

TRAPPIST's planetary system was discovered by a team led by Michaël Gillon, a Belgian astronomer[287] at the University of Liege,[15] in 2016[73] during observations made at La Silla Observatory, Chile,[220][288] using the TRAPPIST telescope; the system's discovery was based on anomalies in the light curves[aq] measured by the telescope in 2015.

The observations of TRAPPIST-1 are considered among the most important research findings of the Spitzer Space Telescope.[290]


 * Why?

Public reaction and cultural impact

The discovery of the TRAPPIST-1 planets drew widespread attention in major world newspapers, social media, streaming television and websites.[293][294]


 * Why such widespread attention?
 * Chat GPT advises:


 * "Earth-sized planets: The TRAPPIST-1 system is notable because it contains seven planets that are roughly the size of Earth. The prospect of finding Earth-sized planets is exciting because it raises the possibility of habitable environments and the potential for extraterrestrial life.


 * Habitable zone: Several of the TRAPPIST-1 planets orbit within the star's habitable zone, also known as the Goldilocks zone. This is the region around a star where conditions may be just right for the presence of liquid water, a crucial ingredient for life as we know it. The presence of potentially habitable planets generated immense interest and speculation about the possibility of finding life beyond Earth.


 * Proximity: The TRAPPIST-1 system is relatively close to Earth, at a distance of approximately 39 light-years. While still incredibly far away, this proximity in astronomical terms made the system more accessible for future observations and potential follow-up studies.


 * Multi-planet system: The fact that the TRAPPIST-1 system contains seven planets orbiting the same star is remarkable. Multi-planet systems provide researchers with a unique opportunity to study planetary formation and dynamics, as well as the potential for complex interactions among the planets.


 * Potential for follow-up observations: The discovery of the TRAPPIST-1 planets generated excitement because it presented an opportunity for further scientific investigation. Astronomers and researchers hoped to use more advanced telescopes and observational techniques to gather additional data on these planets, including their atmospheres and potential signs of life.


 * Public interest in exoplanets: Over the years, there has been a growing interest among the general public in the search for exoplanets (planets orbiting stars outside our solar system). The TRAPPIST-1 discovery captured the public's imagination and fascination, leading to extensive coverage in major newspapers, social media platforms, streaming television, and websites.


 * The combination of these factors—Earth-sized planets, potential habitability, proximity, a multi-planet system, potential for follow-up observations, and public interest—contributed to the widespread attention and coverage the TRAPPIST-1 discovery received." Sandbh (talk) 06:54, 5 July 2023 (UTC)

Exoplanets are often featured in science-fiction works; books, comics and video games have featured the TRAPPIST-1 system, the earliest being The Terminator, a short story by Swiss author Laurence Suhner published in the academic journal that announced the system's discovery.[303]

Scientific importance

TRAPPIST-1 has drawn intense scientific interest.[182]


 * Why?

The role EU funding played in the discovery of TRAPPIST-1 has been cited as an example of the importance of EU projects,[292] and the involvement of a Moroccan observatory as an indication of the Arab world's role in science.

Exploration

TRAPPIST-1 is too distant from Earth to be reached by humans with current or expected technology.[326]

Oppose, General comment
"Water" is mentioned so many times in the article (60) that I found it hard to keep track of its relevance.

--- Sandbh (talk) 04:59, 10 June 2023 (UTC)
 * Noting, this oppose was entered as a heading on July 5, over a June 10 sig. Sandy Georgia (Talk)  13:16, 5 July 2023 (UTC)
 * Dealt with some things. On why the star is so important: I dunno, sorry. Probably because of the multiplicity. On the topic sentence question, I think you mean a lead-like sentence in every section explaining what it is about? If so, I don't think that's standard in any article - it would be the header's job and you can't easily source such a sentence. Jo-Jo Eumerus (talk) 07:19, 10 June 2023 (UTC)


 * ? Gog the Mild (talk) 17:52, 27 June 2023 (UTC)
 * Thanks . Real life obligations will delay my response but I will get around to it. Sandbh (talk) 07:17, 29 June 2023 (UTC)
 * Am now looking and hope to be able to spend up to a few hours on it, if needs be. Sandbh (talk) 05:19, 5 July 2023 (UTC)
 * Re a lead-like sentence in every section, I am only referring to a lead-like sentence at the start of every paragraph i.e. the topic sentence, so that I can follow the gist or logic of the article just by reading its topic sentences. That's how paragraphs work, to help the reader. Headers are fine to give the article an overarching structure, but they don't stand-in for topic sentences. Sandbh (talk) 06:59, 5 July 2023 (UTC)

Oppose, for now (reluctantly), in light of the article having so many "FAC prose standard" shortcomings, and several other deficiencies. As currently written I feel it does not yet exemplify Wikipedia's *  very best  *  work. I note prose concerns were raised at FAC1 and FAC2. My reluctant qualifier refers to there being insufficient science-based FA's. Sandbh (talk) 07:27, 5 July 2023 (UTC)


 * I don't think that a lead sentence at a paragraph is really a requirement of a FA and it's still an invitation to OR. And to be honest, I think the prose concerns from the previous FACses were largely addressed during the stage before this FAC. I am not sure what else there is to do. Jo-Jo Eumerus (talk) 10:50, 5 July 2023 (UTC)
 * OK, half-nevermind on the above. I didn't notice that you had put more comments. Still, I think most of the actionable ones are done, and with many I think your proposed changes would reduce the quality of the text. So I must disagree with many. I've seen the ChatGPT proposal but some of it borders on OR or is rather imprecise. Jo-Jo Eumerus (talk) 12:14, 5 July 2023 (UTC)


 * Hi Sandbh. I am going to be closing this soon, so wanted to see if there were any last thoughts from you, in addition to the above, for me to take into consideration? Thanks. Gog the Mild (talk) 20:59, 23 August 2023 (UTC)
 * Hi Gog the Mild. Thank you; I'll have a look by tomorrow my time and post my thoughts. Sandbh (talk) 07:35, 25 August 2023 (UTC)
 * I've spent about two hours reading through the article (inc. notes and references) and have noticed about 175 items needing a closer look. I don't know yet if I'll post further comments here or on the talk page. I now intend to review my earlier comments and strike out those that have been addressed. Sandbh (talk) 02:29, 26 August 2023 (UTC)
 * About 75 of the 175 items remain of concern to me in the context that:
 * FA's are supposed to exemplify Wikipedia's **very best** work; and
 * criterion 1a namely "Its prose is engaging and of a professional standard".
 * I intend to write up these concerns tomorrow. Sandbh (talk) 07:13, 26 August 2023 (UTC)
 * Just my opinion, but it's probably best to enumerate such things on the talk page, the FAC main page is already quite long. However, please don't restate the article text while doing so; mixing in comments with the text they pertain to makes it hard to read. Jo-Jo Eumerus (talk) 07:38, 26 August 2023 (UTC)

Jo-Jo Eumerus: I feel the article is within reach of FA prose standard, subject to some copy editing which I've begun. I've so far done the lede, and Discovery and naming sections. I intend to spend the rest of the afternoon on copy editing.
 * I've completed copy editing up to the end of section 3 Planetary system. Sandbh (talk) 13:17, 27 August 2023 (UTC)
 * Now done up to the end of section 4 List of planets. Next step is to look at a single table rather than two in sections 3 and 4. Sandbh (talk) 13:41, 27 August 2023 (UTC)
 * I've done some modifications, for reasons given in the summaries. In the "Resonance and tides" section, did you merely reshuffle sentences or was there a bigger rewrite? Jo-Jo Eumerus (talk) 17:41, 27 August 2023 (UTC)
 * I expect your modifications will be OK.
 * I'll check the "Resonance and tides" section later.
 * There was reshuffling, copy-editing and trimming. Sandbh (talk) 04:37, 29 August 2023 (UTC)
 * I've now replaced the two tables in sections 3 and 4, with one consolidated table in section 4. Sandbh (talk) 12:57, 28 August 2023 (UTC)
 * I've finished copy-editing. I believe there are 25 outstanding items where I'll need your technical advice and support. I'll post these to the talk page of this FAC page. Sandbh (talk) 01:41, 29 August 2023 (UTC)
 * I've placed the list of o/s items on the talk page. Sandbh (talk) 02:26, 29 August 2023 (UTC)
 * Actioned them, but I've noticed that you removed the margins of error when merging the tables. Please don't do that; it gives a misleading impression about the accuracy of these figures. Also, the footnotes added in that edit are now completely unsourced. Jo-Jo Eumerus (talk) 10:06, 29 August 2023 (UTC)
 * I've added a note about margins of error just underneath the table heading. For sources, these were included with the legend just underneath the table. Sandbh (talk) 06:07, 31 August 2023 (UTC)
 * I don't think this solves the issue, and to be honest I think the margins of error should remain in the table. Here the need for accuracy outweighs clutter problems, as even scientists sometimes come to bogus conclusions by taking values while ignoring the MoE. Jo-Jo Eumerus (talk) 09:13, 31 August 2023 (UTC)
 * Noted. I intend to have a look at this shortly (later this afternoon my time). Sandbh (talk) 02:23, 1 September 2023 (UTC)
 * I moved the MoE back into the table. All columns remain sortable. Sandbh (talk) 06:09, 1 September 2023 (UTC)

I expect the only things left after that will be some technical issues where I'll need your help.

BTW the flow of the article now appears logical with the exception of the two property tables, which is something I intend to address during copy editing.

Gog the Mild: I seek your indulgence to leave the article on the FAC list while I complete my ce and Jo-Jo Eumerus and I tackle any finally o/s technical issues. I anticipate being able to support the article thereafter. Sandbh (talk) 03:13, 27 August 2023 (UTC)

Kusma: support
Saw this on Urgents, planning to review, but it might not happen until the weekend. —Kusma (talk) 22:39, 5 July 2023 (UTC) Further sections later! —Kusma (talk) 22:10, 6 July 2023 (UTC) Second pass at lead section: Overall a very interesting read, worth more detailed scrutiny by others instead of timing out. I am a bit concerned by the imbalance between study of the star and scientific speculation about its planets in the article, and would suggest another look at images and their captions. And of course, some smaller things as mentioned above need to be looked at. —Kusma (talk) 09:56, 9 July 2023 (UTC)
 * The lead seems to be on the shorter side; does it really have everything important in the article?
 * Expanded a bit, but if there are other things that can be added, let me know. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * The distance doesn't need to be stated twice (once from Earth, once from Sun); would suggest to drop the first one for simplicity.
 * Just re @Anarchyte, the distance between Earth and Sun is 8 light minutes (0.000016 light years), so the distances from Earth to Trappist-1 and from Sun to Trappist-1 are the same within the tolerance given (and there is no need to account for seasonal variations). —Kusma (talk) 07:02, 7 July 2023 (UTC)
 * Um, where does it show an additional distance. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * In the first paragraph of the lead section: "TRAPPIST-1 is a cold dwarf star discovered in 2000 in the constellation Aquarius about 40.66 light-years away from Earth, [...] Located 40 light-years (12.47 parsecs) from the Sun" we have the 40 light years twice, once from Earth, once from the Sun. —Kusma (talk) 13:02, 7 July 2023 (UTC)
 * ...talk about me not noticing. I've deleted the Sun mention, the Earth one works just as well and Sun-Earth distance isn't even a rounding error here. Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)
 * Precision in the lead is inconsistent (40.66±0.04 light-years, but "about 2,566 kelvins" instead of 2,566±26 K)
 * Done. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * Description: I am a bit lost after looking at the comparisons. The density is 0.09/(0.12)^3=52 times larger than that of the Sun, and 100 times that of roughly equal-sized Jupiter?
 * Yes; one thing about stars is that their densities can vary widely. A neutron star packs a mass larger than the Sun in a volume smaller than many cities. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * "TRAPPIST-1 is cold enough for condensates to form in its photosphere" what kind of condensates?
 * Presumably vanadium and iron oxides, but I am hesitant to spell it out w/o a source specifically about TRAPPIST-1. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * "The star emits faint radiation at short wavelengths such as x-rays and UV radiation[i], as measured with the XMM-Newton satellite[39] and other facilities[40] with low precision.[41] There is no detectable radio waves.[42]" can you rewrite this? "Low precision measurements from XMM-Newton and other facilities show that the star emits faint radiation at short wavelengths (ultraviolet and X-rays)." For the last sentence, either "there are no detectable radio waves" or "There is no detectable emission in the radio frequency spectrum".
 * Done. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * It could be helpful to give a short description of what red dwarfs are.
 * Done. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * "earlier measurements of 1.4 days" this is more "history of discovery and observation" than it is "description".
 * Yes, but it would be somewhat disconnected from the rest of the section if put there. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * "the effect of bright spots on the luminosity of TRAPPIST-1 may lead to the planets' densities being underestimated by 8$+20 -7$ percent" first, what does the notation mean? is it necessary to use such notation here? second, do we need to talk about people being wrong about their measurements of the planets in a section about the star?
 * It means that the margin of error isn't identical between the directions. I've moved it down. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * "Dong et al. (2018) simulated the observed properties of TRAPPIST-1 with a mass loss of 4.1×10^−15 solar masses per year" but we know that the mass loss is ten times greater from the previous sentence, so why do we care about this simulation using wrong data? Or am I misunderstanding this?
 * No, we don't know which mass loss estimate is more exact, I think. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * If that is the case, you shouldn't present one of the estimates in wikivoice and the other one with attribution. —Kusma (talk) 09:56, 9 July 2023 (UTC)
 * Fixed. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * If the mass loss due to stellar wind continues at the same rate indefinitely, won't the star be gone before the "ten trillion years" that it is supposed to shine?
 * Not discussed in the specific context of TRAPPIST-1, but the stellar wind weakens over time as stars spin down. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * Overall the "Description" section has lots of short paragraphs and subsections breaking it up into very short pieces. I am wondering whether it is possible to improve the flow.
 * Hmm. Part of the issue is that when we talk about TRAPPIST-1 we generally mean the planets, with the star's properties coming in incidentally. So there isn't much to say about the star itself. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * That is at odds with the first sentence of the lead, which declares the article to be about the star, not about its system. Proxima Centauri also has interesting exoplanets, but they do not dominate the article. —Kusma (talk) 09:56, 9 July 2023 (UTC)
 * The thing is that TRAPPIST-1 derives its notability mainly from the planets, unlike Proxima Centauri which has independent sources of notability. It's about 1/3 star and 2/3 planet, here. Since the topic is primarily discussed under the name of the star, the article is titled after the star. I've edited the lead. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * Planetary system: "The TRAPPIST-1 planetary system" table has some units in the table (M_earth, R_earth), some in the header (days, AU). Might be better to move all into the header and write out "in earth masses" or something like that.
 * Looks like this is a template issue - Template:Orbitbox planet begin and Template:Orbitbox planet apparently can't have the units spelled out. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * Might work better without those templates then? —Kusma (talk) 12:57, 10 July 2023 (UTC)
 * I've modified the template so that now units should show up. Jo-Jo Eumerus (talk) 16:44, 10 July 2023 (UTC)
 * The mass unit is listed in header and in the table, while the radius unit is only in the table. —Kusma (talk) 20:50, 11 July 2023 (UTC)
 * Does it work now? Jo-Jo Eumerus (talk) 06:13, 12 July 2023 (UTC)
 * "The radii of the planets are estimated to range between 75% and 150% of Earth's radius" according to the previous table, we know this with higher accuracy.
 * Done. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * File:PIA21427 - TRAPPIST-1 Planetary Orbits and Transits.ogv is an animation in two parts, and the caption does nothing to explain the second part of the animation. The "planetary surfaces are speculative" seems to refer to File:PIA21424 - The TRAPPIST-1 Habitable Zone.jpg; in the animation, we have colour coding, not speculated surfaces.
 * Changed. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * You dropped the "speculative" completely now; I think it would work fine for the other image. —Kusma (talk) 12:58, 10 July 2023 (UTC)
 * Added it there. Jo-Jo Eumerus (talk) 16:44, 10 July 2023 (UTC)
 * Generally the Planetary system section is very good, but perhaps a bit long for an article about the star.
 * That's because the notability of the star stems in large part from its planets. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * Habitable zone: "The presence of liquid water on any of the planets depends on several other factors, such as albedo (reflectivity),[141] the greenhouse effect,[142] and the presence of an atmosphere." Erm, can there be a greenhouse effect without an atmosphere? That's what this sentence suggests.
 * Corrected. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * "While the TRAPPIST-1 planets appear in an analysis of potential exomoon hosts, they do not appear in the list of habitable-zone exoplanets that could host a moon for a substantial time.[157] Despite these factors, it is possible the planets could host moons." Can you simplify this? Are you just saying that studies show it is possible that the planets have moons, but they could not have them for a "substantial time" (any idea what the 10^n years exponent is here?)
 * No, it means that one study found that in a list of exoplanets, including TRAPPIST-1, found several that can host moons, and these "several" do not include TRAPPIST-1. Explained "Substantial" Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * "Hydrogen-rich exospheres[ah] may be detectable[204] but have not been reliably detected,[205] except perhaps for TRAPPIST-1b and 1c by Bourrier et al. (2017).[177][14]" So does this mean that if these exospheres exist, we could detect them, but we have only detected hints of them on b and c, and nothing elsewhere?
 * Yes. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * Stability: The caption of File:Curva de luz de TRAPPIST-1 que muestra los eventos de disminución de la luz causados por el tránsito de los planetas.png explains what happens in the animation above; try to explain also in that caption.
 * Done. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * "TRAPPIST-1 is moderately to highly active[aj]" sometimes, for example here, I think some footnote content would work better in the main text. The number of footnotes looks a bit excessive (says me, a hypocrite who recently had to figure out in real life how to get LaTeX to display more than 26 alphabetical footnotes).
 * In this specific case, I think trying to spell out the definition of "active" in text would be more distracting than explanatory. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * "The stellar wind from TRAPPIST-1 may have a pressure 1,000 times larger than that of the Sun" at the same distance?
 * Specified. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * List of planets: "Other characteristics" as the table heading isn't a great start for this section. Having to scroll between this table and the previous one is also not ideal. Have you tried combining the tables, or at least keeping them together?
 * No, but only because table formatting is hard and they cover slightly different topics - one parameters relevant to the entire system, the other planet-specific ones. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * The second table is lacking important context about the planets (radius, mass, orbital period, semimajor axis). —Kusma (talk) 13:05, 10 July 2023 (UTC)
 * Do we prefer to duplicate the information in the second table, or some other arrangement? The formatting of tables is a nightmare. Jo-Jo Eumerus (talk) 16:44, 10 July 2023 (UTC)
 * I'm not sure what would work best, but I think a combined table is worth trying. Table formatting is indeed a nightmare; the good news is that it is the one thing where using the Visual Editor actually helps. —Kusma (talk) 08:17, 11 July 2023 (UTC)
 * That would not be me, though; merging two unrelated tables is not something I do very well. Jo-Jo Eumerus (talk) 16:50, 11 July 2023 (UTC)
 * If you can't merge the tables, could you at least try to not start the section with the context-free words "Other characteristics"? Other that what? (Imagine a reader interested only in the planets and opening only this section on mobile). —Kusma (talk) 20:52, 11 July 2023 (UTC)
 * Sure, that's done. Jo-Jo Eumerus (talk) 06:13, 12 July 2023 (UTC)
 * With the new title, I can live with the separate tables. Table + image and no text before the subsections start isn't ideal, but I don't have a good suggestion what to put there at the moment. —Kusma (talk) 16:47, 13 July 2023 (UTC)
 * File:TRAPPIST-1 system to scale.svg seems a bit redundant with other images.
 * Yeah, that one only covers the distances. Is there a better place. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * I don't think it is needed at all. If you keep it, at least tell people it can be scrolled to the side. —Kusma (talk) 13:09, 10 July 2023 (UTC)
 * Need a clarification whether putting such advice in the caption is consistent with style expectations. Jo-Jo Eumerus (talk) 16:44, 10 July 2023 (UTC)
 * TRAPPIST-1b: I think piping average distance from its star is bad; as the eccentricity is very small, the semi-major axis and average distance are going to be very similar in this case, but they are fundamentally different concepts.
 * Yeah, that one was only because finding a source to hang onto an explanation of semi-major axes was a nightmare. Not having it had people wonder what a semi-major axis is, if memory serves. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * I find it unacceptable the way it is right now. Also, the way you have it, you give an average distance from the star for TRAPPIST-1b, while you give the semi-major axis for the other planets. Just use a footnote if you think "semi-major axis" needs to be explained, do not pipe different concepts to each other. —Kusma (talk) 13:14, 10 July 2023 (UTC)
 * Unpiped the link; I am inclined to not add a footnote until people ask for one. Jo-Jo Eumerus (talk) 16:44, 10 July 2023 (UTC)
 * Possible life: shouldn't this be "Possibility of life"? "Possible life" sounds more speculative
 * Hmm, that's true, but here we are discussing not only whether it exists but also how it might manifest itself. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * Research history and reception: the history of discovery comes very very late in the article. Have you thought about other ways to structure this article?
 * Not really, I was following the unwritten convention across Wikipedia topics that the topic itself comes before its reception. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * I'm talking about history, not reception. Jupiter has history before the moons, Europa (moon) has its discovery as the first section. I would expect discovery and naming right after the lead section also for the present article, and certainly not after all of the properties of individual planets and speculation about life. —Kusma (talk) 13:20, 10 July 2023 (UTC)
 * I see, but my assumption is that folks coming here are more likely interested in what the planets and the star are, than about their research history. Jo-Jo Eumerus (talk) 16:44, 10 July 2023 (UTC)
 * In my view the discovery and naming are defining features that should be treated early on, as in the articles I linked to. I don't really agree with your argument for doing it differently here. (We don't put a celebrity's love life at the top of their articles, even if many of our readers are interested more in that than in their actual accomplishments). —Kusma (talk) 08:14, 11 July 2023 (UTC)
 * Looks like we'll need a third opinion here. Jo-Jo Eumerus (talk) 16:50, 11 July 2023 (UTC)
 * Exploration: "even a theoretical interstellar probe travelling at the speed of light would need decades to reach the star." from Earth's point of view... the probe would reach the destination instantly, as it doesn't have to travel a long distance.
 * True, but again needs an explanation not easy to source. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * As I said above, perhaps you should clarify that this is an article about the star system, not just some random dwarf star.
 * Done. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * Overall, still too short I think. There is a lot of information that could be put here: planetary sizes, the flatness and circularity of the orbits, that the plane is nicely aligned so the planets pass in front of their star from our point of view, massive amounts of planetary science speculation what the planets could be like. Lack of moons.
 * Added a bit more. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * The possibility of life and the subsequent impact on science, public perception and science fiction merits a longer treatment than "The system has drawn interest from researchers and in popular culture."
 * Problem is that most sources don't provide much detail on how exactly it draws interest. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)


 * To summarise: we disagree about the structural question whether the discovery and naming section should come much earlier, and about the beginning of the "List of planets" section (I think there should be text before the table, and I am not too happy about the table itself or the wide image). Other than these disagreements, this is an excellent article worthy of support; I would be happy to hear other opinions and will gladly shut up about these issues when it turns out I am the only one who thinks this way. —Kusma (talk) 20:58, 11 July 2023 (UTC)
 * Just to be clear, my point about the table isn't that I disagree with merging the tables. Jo-Jo Eumerus (talk) 06:13, 12 July 2023 (UTC)
 * Right. So our only major disagreement left is the sorting of the sections, which I will also shut up about if most other people think it is better the way it is. —Kusma (talk) 16:49, 13 July 2023 (UTC)

Discussion

 * I have seen elsewhere that Sandbh strongly believes that there should be a topic sentence for each paragraph (so the reader can skim paragraphs for topic sentences and get the gist); I agree that may be generally and even a highly useful style of writing outside of Wikipedia, on Wikipedia, it is quite often an invitation to original research, which is and can be a much bigger problem. (This problem is present throughout the FAs of one now-deceased but formerly prolific FA writer.). While I appreciate Sandbh's intent, I feel it not helpful here, and encourage FAC Coords to take personal preferences into account relative to FA criteria. It should also be noted how damaging it is to fill a FAC page with personal preferences in terms of discouraging further reviews from others; this kind of lengthy commentary did not belong sitting at FAC for over a month, discouraging other reviews, and should have been placed on article talk. Sandy Georgia  (Talk)  13:10, 5 July 2023 (UTC)
 * Separately, noting that this contrary-to-FAC instructions system in use lately, forcing to sub-headers which are explicitly discouraged by the FAC instructions, results in things like an oppose registered on July 5 over a June 10 commentary which sat on this page for almost a month without the original editor returning to strike or move addressed comments. This is misuse of this page that has prejudiced the article. If a reviewer does not return to strike and remove addressed comments for almost a month, FAC Coords should be moving them off the page so the FAC can proceed. Sandy Georgia  (Talk)  13:16, 5 July 2023 (UTC)
 * Hi and thanks for the input. Re the first part of your comments, I think that you will find that the coordinators are on pretty much the same page as you re personal preferences, bearing in mind that that one editor's personal preference may be another's strict adherence to policy and/or FA criteria. Given that I gave the prose of this article a (rough and ready) copy edit immediately prior to its nomination you can guess where I sit re this specific case.
 * Re your other comments, it may well be that negative comments perceived as personal preferences are likely to generate more input from experienced reviewers rather than discourage them. In any event, coordinators are cautious about being seen as dismissive of critical comments, whether or not they personally feel that the criticism amounts to personal preference. (Again, note that I copy edited the prose immediately prior to nomination.) Few editors oppose at FAC lightly and given that coordinators will be taking them strongly into account when closing ("the main thrust of the process is to generate and resolve critical comments in relation to the criteria, and ... such resolution is given considerably more weight than declarations of support") we want to advertise such critical comments, so that other editors can agree or otherwise with them.
 * And the coordinators are of course perfectly capable of deciding that a nomination has a consensus to promote in spite of an open and well reasoned Oppose. You probably noted me doing just that three days ago.
 * I have added this to Urgents.
 * And thanks again for the thoughts above, which I hope that editors considering reviewing will take on board. Gog the Mild (talk) 13:54, 5 July 2023 (UTC)
 * Thanks, Gog; I'm concerned that the voluminous commentary sitting here with no response for almost a month kept other reviewers from digging in, and I hope we will see additional review now. It seems unjust that this article would need to go for a fourth FAC after so much considerable review, including at PR.  Sandy Georgia  (Talk)  13:57, 5 July 2023 (UTC)
 * PS, in Sandbh's defense, I should add that in my own writing, I have tried to take their concern about organizing paragraphs around topic sentences on board as long as those topic sentences can be cited. In the writing of the other editor I mentioned, the sources are not available online, and in almost every case, those articles have had to be defeatured because no one has been able to sort whether these "topic sentence summaries" are original research or can be cited.  I'd not like to see that problem introduced here, and agree with Jo-Jo for refusing to go there.  That is, I believe Jo-Jo has reasonably addressed everything that should be addressed in Sandbh's oppose. Sandy Georgia  (Talk)  14:09, 5 July 2023 (UTC)
 * The nominator may wish to consider placing a polite neutrally phrased request on the talk pages of a few of the more frequent FAC reviewers or on the talk pages of relevant Wikiprojects, or of editors they know are interested in the topic, or who have contributed at PR, or reviewed at previous FACs, or edited the article, which may help attract further reviewers. Gog the Mild (talk) 14:14, 5 July 2023 (UTC)
 * My contribution, but I feel awkward about that in spite of its neutrality, because this new system of using headings introduces POV (the first thing a new reviewer will see is my support in a bold heading). Sandy Georgia (Talk)  14:34, 5 July 2023 (UTC)

During the FAC process of one article that I nominated a reviewer used the FAC talk page 'due to length' which was very thoughtful. The talk page of this FAC has not been used so far, surely it would be fair for co-ords to move lengthy comments to an FAC talk page? Nimbus (Cumulus nimbus floats by)  14:42, 5 July 2023 (UTC)


 * YES. Even more so when the reviewer is not striking comments that have been addressed.  It is not unreasonable to expect the reviewer who is opposing to have the voluminous post moved to talk, and to ask them to resummarize anything they feel is still outstanding.  The placement  of this amount of text on a FAC page, where immediate changes were not responded to for almost a month, is not how the FAC process should be used and introduced unjust prejudice to the article. Sandy Georgia  (Talk)  16:23, 5 July 2023 (UTC)

Support from Anarchyte
Looking to become more familiar with the FA process, so happy to review this (I've read ). Forgive me if I make any glaring rookie mistakes. Note that I have no experience with astronomy, so this review is purely "how does an outsider perceive this article?" I understand reviews are needed urgently, so I'll start tomorrow and finish within the next couple of days. Anarchyte ( talk ) 12:24, 6 July 2023 (UTC)


 * that's a valid, useful, and helpful kind of review! If you are unsure about the FA standards, one thing you might do is put your initial commentary at Wikipedia talk:Featured article candidates/TRAPPIST-1/archive3, or on article talk, and then summarize your impression (support, oppose, comments, all concerns resolved, etc.) back to this page. Sandy Georgia  (Talk)  13:58, 6 July 2023 (UTC)
 * Thank you for the note, . I've written a couple of FAs and reviewed a few in the past, but I've been meaning to devote more time to writing articles so what better way than to increase participation in the FA process? I included the mention of inexperience as a note that I might be unaware of the subject-specific or obscure MOS requirements that wouldn't have mattered for what I've written. Anarchyte  ( talk ) 14:14, 6 July 2023 (UTC)


 * General comments
 * Lead says discovered in 2000. #Research history and reception says 1999.
 * I believe this was discussed elsewhere in this conversation? Is it now resolved? Losing track a bit myself... Jo-Jo Eumerus (talk) 06:11, 13 July 2023 (UTC)


 * Lead
 * I've looked at 's initial comments to make sure we don't overlap, but I disagree with removing either the distance from the Earth and Sun. However, I think the current construction of the first paragraph is a bit jumpy. It would be better if the distances were mentioned simultaneously, with the secondary one paranthesised: i.e., "40.66±0.04 light-years away from Earth (40 light-years from the Sun, or 12.47 parsecs)". Alternatively, the distance to the Sun could be left outside of parentheses and have the opening sentence end there: "TRAPPIST-1 is a cold dwarf star in the constellation Aquarius 40.66±0.04 light-years away from Earth and 40 light-years from the Sun (12.47 parsecs). The star has a surface temperature...". As a reader, I'm more interested in knowing how far away it is from Earth than the Sun which is why I'd mention Earth first.
 * Based on the reply from Kusma above, I now understand why there's some redundancy here. However, if it's decided that the distance from Earth should be cut, then the distance parameter in the infobox should be adjusted accordingly (currently, the +- is only provided in the context of the Earth. If it's applicable to both, then the lead should reflect this).  Anarchyte  ( talk ) 07:33, 7 July 2023 (UTC)
 * Ah, so it's in the infobox? I am inclined to have the measurement in only one place; which do folks prefer? Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * Perhaps the "about 40.66 light-years from Earth" and the "12.47 parsecs" can stay in the lead (i.e., limit the measurements from the Sun to only parsecs), while the exact "40.66 ± 0.04 ly" can remain in the infobox and main article. Although, the infobox needs to be updated to establish what the distance is measuring from. Anarchyte  ( talk ) 13:31, 7 July 2023 (UTC)
 * Keeping the infobox and article value detailed seems correct (the difference between to-Earth distance and to-Sun distance is too small to matter) Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)
 * The dates in the lead would benefit from being together. Being discovered in 2000 does not lead into its radius. It does however provide an introduction to the history of its observations.
 * Rearranged. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * This works. Please also see my comment in general regarding the discovery date. Anarchyte  ( talk ) 13:31, 7 July 2023 (UTC)
 * There is a footnote in the discovery section about the data retrieval taking place in 1999 and the data analysis in 2000. Which year should be preferred? Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)
 * There is nothing outside the lead (including in footnotes) that mentions the year 2000. Anarchyte  ( talk ) 03:12, 9 July 2023 (UTC)
 * Yeah, that's specified by the publication date of the source. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * How about have the lead say "Its discovery was first published in 2000" and then have Research history and reception say "TRAPPIST-1 was discovered in 1999 and published in 2000[keep footnote as-is]...". Anarchyte  ( talk ) 15:08, 10 July 2023 (UTC)
 * Did something along these lines. Jo-Jo Eumerus (talk) 16:44, 10 July 2023 (UTC)
 * The lead mentions 2000 but the main body only mentions it in a footnote. I think it's important that it's written out plainly. Anarchyte  ( talk ) 14:30, 11 July 2023 (UTC)
 * I guess it depends on which date is more important. Jo-Jo Eumerus (talk) 16:50, 11 July 2023 (UTC)
 * Sorry for the delay: I read this and then forgot to reply. Moving it from the note to the main text is all that is required to remove the inconsistency between the lead and the prose. If something is explicitly mentioned in the lead, I don't think it should be hidden inside a note. Anarchyte  ( talk ) 13:49, 15 July 2023 (UTC)
 * Done. Jo-Jo Eumerus (talk) 14:19, 15 July 2023 (UTC)
 * "It takes them" — them? Is this all seven or 2017's five?
 * All seven. See also, my comments to Sandbh about variation reducing clarity. I've restored the "planets". Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * The lead is quite short. It would benefit from details on its scientific importance and a short sentence on its public reception ("TRAPPIST-1 has been the topic of various science-fiction works, including in books, comics and video games."). More weight should be placed on the scientific details, of course, hence the incredibly brief cultural mention.
 * Added a sentence, but I am sure more could be added. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * How about: "The discovery of the system immediately drew interest from researchers; due to the planets' closeness to their star, they have become the easiest exoplanets to study. Alongside similar systems, like Proxima Centauri b, TRAPPIST-1 has encouraged an increase in studies on planetary habitability, and has directly influenced research on the habitability of red dwarfs. The system has also been mentioned in popular culture, including books, comics and video games." Anarchyte  ( talk ) 03:12, 9 July 2023 (UTC)
 * Did something slightly different, per Kusma's advice - does it work? Substantively, one problem I see with your suggestion is that there is far more research on the system's habitability than meta-research. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * I still think there should be more than the final sentence of the lead being "The system has drawn interest from researchers and in popular culture". I based the text above on the "Public reaction and cultural impact" section, which places a lot of emphasis on habitability, so I followed suit. Anarchyte  ( talk ) 08:37, 10 July 2023 (UTC)
 * Added a bit. Jo-Jo Eumerus (talk) 10:30, 10 July 2023 (UTC)
 * How about "Due to the possibility of several planets being habitable, the system has drawn interest from researchers and has appeared in popular culture."? Anarchyte  ( talk ) 15:01, 10 July 2023 (UTC)
 * That works better; added it in. Jo-Jo Eumerus (talk) 16:44, 10 July 2023 (UTC)
 * Description
 * "It is a very close star located at 40.66±0.04 light-years from Earth" — this is not exact, so can "at" be removed?
 * Done. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * "There is no detectable radio waves" — should this not be "are no"?
 * Done. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * "The Kepler and Spitzer Space Telescopes have observed possible bright spots, which may be faculae, although some of these may be too large to qualify as faculae. Bright spots are correlated to the occurrence of some stellar flares." — should be reordered so that the cause (solar flares) comes before the explanation (faculae).
 * I don't think that faculae are either cause or consequence of flares. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * I must have misinterpreted. Anarchyte  ( talk ) 13:31, 7 July 2023 (UTC)
 * "The photospheric features may introduce inaccuracies in measurements of TRAPPIST-1's planets; the effect of bright spots on the luminosity of TRAPPIST-1 may lead to the planets' densities being underestimated by [] percent and to incorrect estimates of their water content." — repeating content here. Could be reduced to "The photospheric features may introduce inaccuracies in measurements of TRAPPIST-1's planets, including their densities being underestimated by [] percent and incorrect estimates of their water content" (or something similar).
 * Done, might be one thing where folks asked for an explanation of "photospheric features" Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)
 * Instead of "and to incorrect estimates of their water content", can it be "and causing incorrect..."? Anarchyte  ( talk ) 13:31, 7 July 2023 (UTC)
 * Done. Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)
 * I'm sure I can have a reasonable guess, but why does the lack of direct observation cause issues in simulations? Something at the end of the sentence like "direct observation, meaning they must be [predicted/guessed/assumed/taken from unreliable data/???]".
 * They must be predicted, yes. A simulation isn't the actual thing, it can be erroneous. Jo-Jo Eumerus (talk) 12:48, 7 July 2023 (UTC)

Will continue later. Anarchyte ( talk ) 06:06, 7 July 2023 (UTC)


 * Planetary system (through to Skies and impact of stellar light)
 * "The inclinations of the orbits relative to the system's ecliptic are less than 0.1 degrees" — could you add a note comparing this to Earth's?
 * Done. Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)
 * Gas giant is linked on second mention rather than first. Same with outgassing.
 * Done. Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)
 * "expected to have compositions that resemble [...] Earth", but then several differences are listed with no explicit similarities mentioned.
 * I think that means "rocky" rather than "gaseous". Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)
 * Is "composition" the correct word? Could "structure" be better? "Composition of Earth" returns 412,000,000 google results, while "Structure of Earth" returns 1,320,000,000. If there's an astronomical difference, ignore this.
 * "Structure" implies a 3D concept, not a chemical one. Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)
 * "Tidal forces are dominated by the star's contributions" — contributions?
 * Fixed. Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)
 * "The interaction could force periodic or episodic full rotations of the planets' surfaces with respect to the star on timescales of several Earth years." — confusing. Is this saying it's possible they're not tidally locked and could complete a full rotation eventually?
 * Yes, one rotation every few Earth years, essentially. Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)
 * "This heat source is likely dominant over radioactive decay, both of which have substantial uncertainties and are considerably less than the stellar radiation received." — unclear where the connection comes from. Is radiation another theory?
 * Radiation in the sense of starlight, not radioactivity. Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)
 * "The same amount of radiation" — "This amount of radiation"?
 * No; it's important that we are comparing two cases with the same radiation. Jo-Jo Eumerus (talk) 17:13, 7 July 2023 (UTC)

Anarchyte ( talk ) 13:13, 7 July 2023 (UTC)


 * General comments
 * I would argue "List of planets" should proceed "Potential planetary atmospheres" as the third section.
 * I am inclined to keep this order, if only because discussion of individual planets happens mostly in other articles. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * Understandable. I'll leave this one unstricken in case other people have opinions, but whether it's changed or not won't affect my support. Anarchyte  ( talk ) 15:01, 10 July 2023 (UTC)
 * I've been thinking about this more and I'd like to hear if anyone else has an opinion on the ordering. Currently, the article has two introductory background sections, a section of in-depth analysis, another introductory background section, then further in-depth analysis. I do think that swapping these two would form a better structure. I've temporarily created User:Anarchyte/sandboxTRAPPIST so that easy comparisons can be made. Anarchyte  ( talk ) 13:59, 15 July 2023 (UTC)
 * A note explaining what an M dwarf is would be good, given the red dwarf article doesn't seem to explore it in layman's terms.
 * There is already one about spectral classes, I think? Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * Yep -- this is already covered. Anarchyte  ( talk ) 08:33, 10 July 2023 (UTC)
 * If you wanted, you could turn the image in the List of planets section into an image map. mw:Extension:ImageMap. Anarchyte  ( talk ) 14:04, 15 July 2023 (UTC)
 * Oy, that seems like a lot of editing work to learn. If someone else wants to do the replacement, they can. Jo-Jo Eumerus (talk) 14:19, 15 July 2023 (UTC)
 * Yep, no obligation, just an idea. Anarchyte  ( talk ) 16:25, 15 July 2023 (UTC)


 * Planetary system (continued)
 * "A synchronously rotating planet might not entirely freeze over if it receives too little radiation from its star because the day-side could be sufficiently heated to halt the progress of glaciation" — can this be reworded to "A synchronously rotating planet might not entirely freeze over because the day-side could be sufficiently heated by the radiation of its star to halt the progress of glaciation"?
 * That would imply that no planet gets enough instellation to stop freezing, which isn't the case here. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * "The effects of volcanic activity may extend the system's habitable zone to TRAPPIST-1h" — if this is so, why isn't it included in the three to four count (which I assume consists of d, e, f, g)?
 * Mostly, I think, b/c the parameters for tidal heating are so unclear that scientists don't like factoring it in when discussing habitability. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * "consistent with inference from observations" — "consistent with the observational inferences"?
 * Done. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)


 * Potential planetary atmospheres
 * "The outer planets are more likely to have atmospheres than the inner planets." — seems too important to have at the end of the second para. Consider moving it so it's the second sentence of the section.
 * Done. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * I meant after "As of 2020, there is no definitive evidence that any of the TRAPPIST-1 planets have an atmosphere, but atmospheres could be detected in the future". Would it be suitable immediately after this? Anarchyte  ( talk ) 08:33, 10 July 2023 (UTC)
 * Ah, done. Jo-Jo Eumerus (talk) 10:30, 10 July 2023 (UTC)
 * "suggests the inner planets most likely have, if any, oxygen-and-CO2-rich atmospheres" — "if any": does this refer to any atmosphere or any planet? Needs clarification.
 * Reordered. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * "TRAPPIST-1 is moderately to highly active" — "TRAPPIST-1 has moderate to high stellar activity"? Stellar activity isn't mentioned outside of the note.
 * Done. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * Should it be "moderately" (as it now says "highly", but "moderate"). Anarchyte  ( talk ) 08:33, 10 July 2023 (UTC)
 * Done. Jo-Jo Eumerus (talk) 10:30, 10 July 2023 (UTC)
 * It's been a while since it was linked, and coronal mass ejections seems confusing, so perhaps relink it in Stability.
 * Done. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)

That's all from me. Anarchyte ( talk ) 03:01, 9 July 2023 (UTC)
 * List of planets
 * "and orbits same" — typo?
 * Done. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * "It may be losing hydrogen at a rate of 1.4×107 g/s based on Hubble Space Telescope (HST) observations" — is there a date for when this observation was made?
 * Of the publication, it was published in 2017 based on 2016 observations. Jo-Jo Eumerus (talk) 21:10, 9 July 2023 (UTC)
 * It's odd that it says "it might be losing hydrogen" (undated) and then "it isn't losing hydrogen" (2017). Should date the first statement, such as "Predictions in 20xx estimate that the planet may be losing hydrogen...". Anarchyte  ( talk ) 08:33, 10 July 2023 (UTC)
 * Done. Jo-Jo Eumerus (talk) 10:30, 10 July 2023 (UTC)
 * May be better to swap it around so it's chronological: "Although 2017 observations showed no signs of the planet losing hydrogen, observations in 2020 by the Hubble Space Telescope (HST) indicate that hydrogen may be escaping at a rate of []." Anarchyte  ( talk ) 15:01, 10 July 2023 (UTC)
 * Done. Jo-Jo Eumerus (talk) 16:44, 10 July 2023 (UTC)
 * Thanks for looking over them . I've replied above. Anarchyte  ( talk ) 08:33, 10 July 2023 (UTC)

To summarise, all of my prose and general concerns have been addressed. The only issue I have left is the arrangement of the "List of planets" section within the article, but I'm happy to let that go if other reviewers disagree with me. Anarchyte ( talk ) 16:25, 15 July 2023 (UTC)


 * Jo-Jo Eumerus ? Gog the Mild (talk) 13:44, 20 July 2023 (UTC)
 * I believe 's section issue is the same as the one mentioned by, but I'll check. Regarding Sandbh's concerns, I've resolved some, but for the others, I have objections to the proposed changes. Jo-Jo Eumerus (talk) 19:06, 20 July 2023 (UTC)
 * I think the section issues are slightly different. Anarchyte seems to say "List of planets" should be moved up before "Potential planetary atmospheres"; I had not thought of that but agree it would be a slight improvement. My point is that I would like to see the first two or three paragraphs of "Research history and reception" moved right after the lead section as "Discovery and naming", which would make this article's structure more similar to other astronomy FAs. You could just try the suggested changes, see what the result is like, and then revert again if you truly hate it? Similar to what Anarchyte said, I would be happy to hear the opinion of other people and would not mind being overruled by reviewer consensus. —Kusma (talk) 20:27, 20 July 2023 (UTC)
 * You know, yeah, it's an improvement. I've enacted 's proposed change. I've tried 's change; how does it look? Also, while more of a personal issue, but I'd love being able to remove that blob of markup that we are using to circumvent the fact that Template:Starbox begin links the same pages repeatedly. That sounds like a maintenance/editability issue in the making. Jo-Jo Eumerus (talk) 06:05, 21 July 2023 (UTC)
 * I like it, and have put a "support" in my section header. —Kusma (talk) 09:20, 21 July 2023 (UTC)

Support. Anarchyte ( talk ) 14:03, 21 July 2023 (UTC)

HF- support
Will review this one soon. Because this FAC is already exceeding my limits to follow easily due to length/poor discussion layout, I plan on leaving any trivial comments at Wikipedia talk:Featured article candidates/TRAPPIST-1/archive3 and posting only major ones that would noteworthy for the non-recused coords and other reviewers here, unless someone objects to that. Hog Farm Talk 23:31, 9 July 2023 (UTC)


 * Awesome! Jo-Jo and HF, please ping me for a new look when HF is done, as there has now been considerable useful commentary since my support.  FYI, I hate the first sentence in the new lead ("noted for" is cliche). Sandy Georgia  (Talk)  14:43, 11 July 2023 (UTC)


 * "are possible considering the large uncertainties in their densities" - but the image to the right references "price measurements of the planet densities"
 * Yeah, that image is overselling the precision. I've commented it out, pending an image edit at commons:Commons:Graphic Lab/Illustration workshop Jo-Jo Eumerus (talk) 06:13, 12 July 2023 (UTC)
 * " Planets b, d, f, g and h are expected to contain large quantities of volatile compounds" - is this a consensus view, or just that of one paper? Because the prior part of the paragraph is listing a bunch of alternatives to the volatile compounds theory
 * I believe this is pretty much the consensus, largely I think because the alternative theories would be hard up at providing densities that low. Jo-Jo Eumerus (talk) 06:13, 12 July 2023 (UTC)

Ready for 'potential planetary atmospheres'; hope to be back tomorrow. Hog Farm Talk 01:52, 12 July 2023 (UTC)


 * "the probability that it does is considerably less than that of Earth" - I think I get what you're trying to say here but it just seems off phrasing-wise, since we know that the probability that Earth supports life is 100%
 * Yeah, I myself don't know how to formulate this - the point is that if we ignore that life currently very definitively exists on Earth, the probability of it forming here is higher than on a TRAPPIST-1 planet. Jo-Jo Eumerus (talk) 06:11, 13 July 2023 (UTC)
 * "Determann, Jörg Matthias (2019). Space science and the Arab world: astronauts, observatories and nationalism in the Middle East. ISBN 978-1-83860-015-0. OCLC 1122719747." - publisher needed
 * "Meadows, Victoria S; Schmidt, Britney E (2020). Planetary astrobiology. ISBN 978-0-8165-4006-8. OCLC 1096534611." - publisher needed
 * "Madhusudhan, Nikku (2020). Exofrontiers: big questions in exoplanetary science. ISBN 978-0-7503-1472-5. OCLC 1285004266." - publisher needed
 * ""Handbook of Scientific Tables". May 2022. doi:10.1142/9789813278523_0001." - uses the cite journal template, but no journal (or any other publisher is provided)?
 * "Short, Kendra; Stapelfeldt, Karl (2017). Exoplanet exploration program update (PDF) (Report)." source link leads to "1 to 10 of 37,576 Results" making the link of dubious utility and the publisher needs provided as well
 * Fixed most of this, but I can't tell what the publisher for the last item is. Jo-Jo Eumerus (talk) 06:11, 13 July 2023 (UTC)
 * - I think it's the NASA Exoplanet Exploration Program; does that seem right? Hog Farm Talk 01:54, 14 July 2023 (UTC)
 * Done. Jo-Jo Eumerus (talk) 07:05, 14 July 2023 (UTC)

I think that's all from me for the first pass. Hog Farm Talk 04:25, 13 July 2023 (UTC)
 * HF, did you still want to take a second look? Cheers, Ian Rose (talk) 13:20, 27 July 2023 (UTC)
 * No, I'm comfortable supporting. Hog Farm Talk 02:49, 28 July 2023 (UTC)

Image review - pass

 * "File:TRAPPIST-1 system to scale.svg" has no alt text. Gog the Mild (talk) 15:36, 14 July 2023 (UTC)
 * VE says that there is alt text, attached to the template. Jo-Jo Eumerus (talk) 16:54, 14 July 2023 (UTC)
 * I am struggling to find it. What does it say? Gog the Mild (talk) 17:13, 23 July 2023 (UTC)
 * You can see it in source mode or using WP:POP. The alt text given is "Distances between TRAPPIST-1 planets are roughly comparable with Earth-Moon distances". —Kusma (talk) 17:51, 23 July 2023 (UTC)


 * All images are appropriately licenced, positioned, captioned and alt texted. Gog the Mild (talk) 18:00, 23 July 2023 (UTC)

Request for update
Asking where we are at this. Jo-Jo Eumerus (talk) 07:27, 2 August 2023 (UTC)
 * We are waiting for it to receive and pass a source review. When/if that happens, one of us will go through with a view to closing it one way or the other. Gog the Mild (talk) 13:12, 2 August 2023 (UTC)
 * It has been suggested that the source review be split between several reviewers. I will start working back through the Reception and scientific importance section. I'm thinking we can have source review sections for each reviewer, stating which section or whatever area of the article they intend to cover. I've started a section below. Coordinators please refactor as necessary for clarity and sanity! Mirokado (talk) 18:53, 8 August 2023 (UTC)

Source review from Mirokado
Working backwards through §Reception and scientific importance. Discussion ongoing about what is needed. -- Mirokado (talk) 21:03, 8 August 2023 (UTC)

I will start by checking the citation links (bullet 3 in the discussion). -- Mirokado (talk) 13:48, 9 August 2023 (UTC)

I am making a few trivial changes, so far related to source checking, en passant: -- Mirokado (talk) 18:51, 9 August 2023 (UTC)
 * §Sources, changed refbegin to specify column width rather than the deprecated number of columns. This is generally more user friendly with better support for different screen widths and will help during the source review since I can set the window width to give a single-column display. -- Mirokado (talk) 14:24, 9 August 2023 (UTC)
 * Changed param names  to   and so on for consistency.

I have now checked all the citations down to Meadows et al. where JBL took over. I may have a few more comments since I took some notes on the way. I was checking the citations themselves for correctness, completeness and consistency. They all correspond to reliable sources, but I have not been checking how well they support the article content in detail. -- Mirokado (talk) 01:38, 14 August 2023 (UTC)
 * some citations use "et al." while others do not (see Agol and Delrez for examples)
 * If you mean the article text, there I don't spell out each name. Jo-Jo Eumerus (talk) 11:29, 11 August 2023 (UTC)
 * I meant that, for example, Agol et al. 2021 has, whereas Delrez et al. 2022 does not. -- Mirokado (talk) 12:49, 11 August 2023 (UTC),
 * Ah. Question here is, do we standardize on 4 or do we let the templates decide? Jo-Jo Eumerus (talk) 20:02, 11 August 2023 (UTC)
 * The templates default to displaying all authors (see Help:Citation Style 1), so we should either add consistently or not at all. Since the citation list is quite long, I suggest adding  to all citations with six or more authors, thus "et al." would hide two or more extra authors and we would not "pick on" just one extra author. -- Mirokado (talk) 00:27, 12 August 2023 (UTC)
 * I am strongly inclined to not arbitrarily shorten the amount of authors displayed, myself. In a references section, I expect an accurate depiction of the authors. Jo-Jo Eumerus (talk) 05:35, 12 August 2023 (UTC)
 * OK (and in fact I agree with you). In that case please remove all occurrences of (66, including one  and one  ). -- Mirokado (talk) 15:15, 12 August 2023 (UTC)
 * Done. Jo-Jo Eumerus (talk) 18:36, 12 August 2023 (UTC)
 * Agol, Delrez and others: fr:Valérie Van Grootel is a Belgian astronomer, so she appears under capital V in alphabetical surname lists, thus Van Grootel, V or Van Grootel, Valérie (with acute accent) depending on the citation (see van (Dutch))
 * Done, I think. Jo-Jo Eumerus (talk) 11:29, 11 August 2023 (UTC)
 * Yes, that is fine now. Thanks.
 * Angosto, Benaglia: these Spanish language citations do not have a  param. -- Mirokado (talk) 08:09, 11 August 2023 (UTC)
 * Done. Jo-Jo Eumerus (talk) 11:29, 11 August 2023 (UTC)
 * Brasser 2022, Delrez 2018 and Miles-Páez 2019: these three have author initials without the full stop, unlike all the others. -- Mirokado (talk) 12:49, 11 August 2023 (UTC)
 * Added full stops. Jo-Jo Eumerus (talk) 20:02, 11 August 2023 (UTC)
 * Barnes et al. 2014: three of the four identifier links provide a longer author list. -- Mirokado (talk) 00:27, 12 August 2023 (UTC)
 * Resolved. Jo-Jo Eumerus (talk) 05:35, 12 August 2023 (UTC)
 * Comparación de los datos de áreas de manchas solares ...: the Bibcode page has a different author list and open access pdf links (including this on articles.adsabs.harvard.edu). Please update the citation accordingly, for example:  Benaglia et al. are the journal editors and we don't normally list those. El Boletín gives an ISSN of 1669-9521 but that is not registered with WorldCat. -- Mirokado (talk) 15:15, 12 August 2023 (UTC)
 * No idea what happened with that citation, but altered it. Jo-Jo Eumerus (talk) 18:36, 12 August 2023 (UTC)
 * Thanks. For those following, the change was to replace the reference by Díaz 2017, 185-186. -- Mirokado (talk) 19:19, 12 August 2023 (UTC)
 * Bourrier 2017: There is a choice of two ISSNs for The Astronomical Journal (listed in the infobox).
 * Added. Jo-Jo Eumerus (talk) 18:36, 12 August 2023 (UTC)
 * I have changed the Madhusudhan 2020 callouts to use the param, so that it is clear in the source that these are chapter-page references, not page ranges. That can help any little scripts that look for page range problems. Please can you check, or say, whether this is needed for Howell 2020, 3-34? -- Mirokado (talk) 06:16, 13 August 2023 (UTC)
 * Probably needed there as well. Jo-Jo Eumerus (talk) 06:49, 13 August 2023 (UTC)
 * OK, done that. -- Mirokado (talk) 07:44, 13 August 2023 (UTC)
 * Delrez et al. 2022: The doi link has a longer author list. -- Mirokado (talk) 14:13, 13 August 2023 (UTC)
 * Expanded, I think. Jo-Jo Eumerus (talk) 16:29, 13 August 2023 (UTC)
 * OK now, thanks. -- Mirokado (talk)
 * Dependencies of Mantle Shock Heating in Pairwise Accretion: although the bibcode and doi links give Gabriel, Travis S. J and Allen-Sutter, Harrison as the authors, the actual article pdf from IOP Publishing gives Gabriel, Travis S. J. and Horn, Harrison W. – I would go with what the article says. -- Mirokado (talk) 19:48, 13 August 2023 (UTC)
 * Done. Jo-Jo Eumerus (talk) 19:59, 13 August 2023 (UTC)
 * Gillon 2020: with only title and author, I have not so far been able to find any information to verify this. -- Mirokado (talk) 20:56, 13 August 2023 (UTC)
 * Added the URL, I got it from WP:RX and still have a PDF copy. Jo-Jo Eumerus (talk) 08:24, 14 August 2023 (UTC)
 * Thanks. Since this is behind a paywall, I have added (this is the only value which indicates no free access, see the CS1 help). -- Mirokado (talk) 03:06, 15 August 2023 (UTC)
 * Gillon et al. 2013: this can use with more information from the provided links: Protostars and Planets VI, Heidelberg, July 15-20, 2013. Poster #2K066. -- Mirokado (talk) 21:17, 13 August 2023 (UTC)
 * Done. Jo-Jo Eumerus (talk) 08:24, 14 August 2023 (UTC)
 * Gillon et al. 2020: the links name two further authors: Lustig-Yaeger, Jacob; Rackham, Benjamin V. -- Mirokado (talk) 21:38, 13 August 2023 (UTC)
 * Added. Jo-Jo Eumerus (talk) 08:24, 14 August 2023 (UTC)
 * Childs et al. 2022 and others: missing or incorrect ISSN for The Astrophysical Journal Letters. WorldCat gives two: 2041-8213, 2041-8205 (this is the printed edition, see the note in Slovenian). There are eight occurrences to check. There are also eight citations for The Astronomical Journal missing the ISSN (one has 0004-6256). -- Mirokado (talk) 22:51, 13 August 2023 (UTC)
 * I omitted the ISSNs for these journals because TAJ does not show one on its website. Jo-Jo Eumerus (talk) 08:24, 14 August 2023 (UTC)
 * Checking further:
 * The Astronomical Journal has 8 citations, one of which has issn=0004-6256, the rest none
 * The Astrophysical Journal has 28 citations, all with issn=1538-4357 so they are presumably OK
 * The Astrophysical Journal Letters has 8 citations, three with issn=1538-4357 (the journal, looks incorrect for the letters), one with issn=2041-8205 (according to WorldCat, the journal letters) and four with none
 * I wanted to convince myself that the WorldCat records are nice and clear, but they are not really, with multiple ISSNs, multiple OCLC records and inconsistent titles.
 * I am reasonably satisfied that we can use issn=0004-6256 for The Astronomical Journal and issn=1538-4357 for The Astrophysical Journal Letters, but if you prefer to omit either I can also live with that. Please just make sure that the issn entries for each journal are either the same or absent. -- Mirokado (talk) 03:06, 15 August 2023 (UTC)
 * I have stripped out these ISSNs; the difficulty in verifying whether they are actually correct leads me to conclude that they are better left out. Jo-Jo Eumerus (talk) 08:36, 15 August 2023 (UTC)
 * OK now, thanks. -- Mirokado (talk) 14:52, 15 August 2023 (UTC)
 * This also seems reasonable to me. (Actually I think it is very defensible to leave off ISSNs altogether, at least as long as we're talking about journals modern enough to have an online existence.)  --JBL (talk) 17:31, 15 August 2023 (UTC)
 * OK now, thanks. -- Mirokado (talk) 14:52, 15 August 2023 (UTC)
 * This also seems reasonable to me. (Actually I think it is very defensible to leave off ISSNs altogether, at least as long as we're talking about journals modern enough to have an online existence.)  --JBL (talk) 17:31, 15 August 2023 (UTC)

Pass for citation links, formatting and the reliability of the sources. I will add any comments about the use of the citations and content coverage below. -- Mirokado (talk)
 * There is a current conversation at Help talk:Citation Style 1/Archive 89 which recommends putting any citation year disambiguation (1979a etc) in the visible date rather than hidden in the year or ref params: this is better for printed versions of the article as well as simplifying the source. Thus I suggest using  instead of , and so on (eight occurrences). I have checked this in preview mode and it works fine. -- Mirokado (talk) 16:28, 17 August 2023 (UTC)
 * @user:Jo-Jo Eumerus: this is still outstanding (sorry, I was away for a few days so didn't remind you earlier) . -- Mirokado (talk) 11:29, 24 August 2023 (UTC)
 * Um, I don't see such a discussion? Also, I think to a lot of people and computers "2020a" in the date parameters would be weird. Jo-Jo Eumerus (talk) 07:45, 25 August 2023 (UTC)
 * Hmm, the link works for me (it will of course be archived later), but this is just one comment in an ongoing conversation so it is well within your discretion to prefer not to do that. Striking. I have no further comments. -- Mirokado (talk) 11:02, 25 August 2023 (UTC)
 * §Habitable zone: "or d, e, and f." has no ref callout. -- Mirokado (talk) 05:47, 17 August 2023 (UTC)
 * Not sure what you mean, but I restored an earlier citation. Jo-Jo Eumerus (talk) 17:49, 17 August 2023 (UTC)
 * Thanks, that is what I meant! (the "callout" in the content as opposed to a "citation" in the sources list). -- Mirokado (talk) 23:43, 17 August 2023 (UTC)

Source review from JayBeeEll
I am doing the same thing as Mirokado, starting from the middle (Meadows et al.) and working my way down. --JBL (talk) 23:24, 9 August 2023 (UTC) More below. I've made it to the end (starting from Meadows). --JBL (talk) 17:51, 11 August 2023 (UTC) Am I supposed to declare a final judgement? I think this article is a pass on the sourcing requirements, at least as far as the portion of the sources I checked. --JBL (talk) 20:13, 23 August 2023 (UTC)
 * The use of ISSNs seems inconsistent.
 * Standardized, although not all sauces have ISSNs. Jo-Jo Eumerus (talk) 08:25, 10 August 2023 (UTC)
 * Some references are to the wrong journal:
 * Morris, Brett M.; Agol, Eric; Hebb, Leslie; Hawley, Suzanne L.; et al. (17 August 2018). "Non-detection of Contamination by Stellar Activity in the Spitzer Transit Light Curves of TRAPPIST-1" is in The Astrophysical Journal Letters, not The Astrophysical Journal
 * Pidhorodetska et al., ditto.
 * Done. Jo-Jo Eumerus (talk) 08:25, 10 August 2023 (UTC)
 * Scheidenberger, Christoph; Pfützner, Marek, eds. (2018). The Euroschool on Exotic Beams. Vol. 5. The S2CID points to Volume 6.
 * Took the s2cid off. Jo-Jo Eumerus (talk) 08:25, 10 August 2023 (UTC)
 * Sein, Alexandr; Duncan, Colton; Zhong, Patrick; Koock, Elise; et al. (2021). STEM Education Through Virtual Space System Design Competitions. The ISBN doesn't seem to work (?).
 * Krissansen-Totton et al. seems to be alphabetized under T instead of K.
 * Resolved both. Jo-Jo Eumerus (talk) 08:25, 10 August 2023 (UTC)
 * Since your fix, (triggered by ) has restored the isbn on Sein et al. that seems wrong or broken.  I'm not sure what the best way to deal with that is.  --JBL (talk) 17:40, 15 August 2023 (UTC)
 * isbn=978-1-62410-609-5|Tried something. Jo-Jo Eumerus (talk) 18:39, 15 August 2023 (UTC)
 * The general fix is to put |isbn = in the citation in question. People will keep running Citation bot on the article or its categories, so an override must be added. Abductive  (reasoning) 00:17, 16 August 2023 (UTC)
 * Per discussion at User talk:Citation bot I've done a somewhat different change to the template so that it goes to cite conference rather than cite book or cite journal. Jo-Jo Eumerus (talk) 08:19, 16 August 2023 (UTC)
 * The useless ISBN link is still there, but I guess one upshot of the discussion there was that "useless link" and "right ISBN" are compatible? --JBL (talk) 20:13, 23 August 2023 (UTC)
 * Seems like they are concluding that the problem is with ISBN, not our use of it. Dunno how to fix this. Jo-Jo Eumerus (talk) 20:33, 23 August 2023 (UTC)
 * The single-author publication by Wolf was another AJ -> AJL; I fixed it (please check my work).
 * There's some funny alphabetization that happens in the W/V region: Wunderlich followed by Valio, Brown, Van Hoolst.
 * Done. Jo-Jo Eumerus (talk) 20:02, 11 August 2023 (UTC)
 * In fact that Brown et al. is a duplicate: the version that's alphabetized under B seems like the better rendition of the reference (it mentions "Gaia collaboration" and the erratum; the later one confusingly has the DOI of the erratum while the other links go to the original paper).
 * Merged them? Jo-Jo Eumerus (talk) 20:02, 11 August 2023 (UTC)
 * Yes, looks good. --JBL (talk) 17:40, 15 August 2023 (UTC)
 * I tend to view MathWorld as a marginal source; I don't know ScienceWorld as well but I would tend to regard it similarly. It's being used in a marginal and inoffensive way here for uncontentious information (to reference, in a footnote, the definition of celestial equator), but I do wonder if there's not some better alternative.  (Not crucial.)  The other sources I reviewed looked fine at first glance.
 * In my experience, sourcing such definitional things is extremely hard if not impossible. Inclined to say that unless someone can find a better source, it's not something we can just expect a better source for. Jo-Jo Eumerus (talk) 20:02, 11 August 2023 (UTC)
 * Easy to find textbooks on astronomical coordinates: Or a specialised encyclopaedia: . —Kusma (talk) 15:25, 12 August 2023 (UTC)
 * OK, that's in. Jo-Jo Eumerus (talk) 18:36, 12 August 2023 (UTC)
 * Great, thanks. --JBL (talk) 17:40, 15 August 2023 (UTC)
 * On the subject of reliability of sources: there's a huge RfC going on at WT:NJOURNALS, and incidentally to that discussion, specifically mentioned International Journal of Astrobiology (three citations) and Journal of Physics: Conference Series (two citations) as having problematic histories.  In the case of JoP:CS, this is explained in our article; my view would be that one should double-check that neither of the articles cited here were affected, but otherwise not to worry about it.  For IJA, I don't know the background of JoelleJay's comment, so I don't know exactly how to interpret it in the context of this article.  In all cases it suggests to me that maybe it is worth a few minutes to see if there is an alternative source available for the cited material.  Aside from this (and the ScienceWorld issue dealt with above), the sources looked reliable to me.  --JBL (talk) 17:50, 15 August 2023 (UTC)
 * International Journal of Astrobiology seems to have one crankish article but I wouldn't disqualify just for that. On Journal of Physics: Conference Series, I dunno, I wouldn't necessarily call a single scandal as a disqualifier unless there is a pattern. Especially as the claims sourced to them don't strike me as outlandish or WP:EXCEPTIONAL. But that may be just me. Jo-Jo Eumerus (talk) 18:39, 15 August 2023 (UTC)
 * I think your position on this is reasonable. --JBL (talk) 20:13, 23 August 2023 (UTC)
 * TBH, I am not 100% myself of how this works - ? Jo-Jo Eumerus (talk) 20:33, 23 August 2023 (UTC)
 * A declared 'pass' makes it clear, thanks guys. Cheers, Ian Rose (talk) 20:56, 23 August 2023 (UTC)
 * Very few articles get a 100% check on sourcing, virtually none that aren't by first-time nominators. The efforts by JBL and Mirokado above constitute a thorough check of the sourcing IMO and I am going to accept their two passes as an overall pass on the source review. Gog the Mild (talk) 21:01, 23 August 2023 (UTC)

SC

 * Support Excellent article. - SchroCat (talk) 12:58, 13 August 2023 (UTC)

Support by Sandbh
All of my concerns have now been addressed. Sandbh (talk) 02:39, 2 September 2023 (UTC)

Coord note
Thanks all, it appears critical comments are now resolved. I do however share 's distaste for "noted for" in the opening sentence -- anything in WP should be notable. I see that this version six months ago didn't require the phrase; is there any reason we shouldn't return to that, minus "in the constellation Aquarius", which is currently in the second sentence? Cheers, Ian Rose (talk) 19:17, 2 September 2023 (UTC)


 * OK, removed it. Jo-Jo Eumerus (talk) 21:24, 2 September 2023 (UTC)

Ian Rose (talk) 08:57, 3 September 2023 (UTC)