Wikipedia talk:Featured article candidates/TRAPPIST-1/archive3

TFA blurb review
TRAPPIST-1 is a cool red dwarf star with seven known exoplanets. It lies in the constellation Aquarius about $40.66$ light-years away from Earth. It has a mass of about 9% of the Sun. It is estimated to be 7.6 billion years old, making it older than the Solar System. The discovery of the star was first published in 2000. Observations in 2016 from the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) led to the discovery of two orbiting terrestrial planets, and five others of unknown types. It takes the seven planets between about 1.5 and 19 days to orbit around the star. They are likely tidally locked to TRAPPIST-1, leading to permanent day on one side and night on the other. Their masses are comparable to that of Earth. Up to four of the planets orbit at distances where temperatures are suitable for the existence of liquid water, and are thus potentially hospitable to life. This has drawn interest from both researchers and popular culture.

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Hi and congratulations. A draft blurb for this article is above. Thoughts, comments and edits from you or from anyone else interested are welcome. Gog the Mild (talk) 12:27, 12 September 2023 (UTC)


 * OKish, but I'd wait until we have some evidence of habitability (i.e friendly atmospheres on the outer planets) before TFAing this. Jo-Jo Eumerus (talk) 15:02, 12 September 2023 (UTC)


 * Here's a copy edited version, with 978 characters:


 * TRAPPIST-1 is a cool red dwarf star, with seven known exoplanets. It lies about 40.66 light-years from Earth, in the constellation of Aquarius. With about 9% of the Sun's mass, it is estimated to be around 7.6 billion years old, predating the Solar System. The existence of TRAPPIST-1 was first recorded in 2000. Observations in 2016 using the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) revealed the presence of two orbiting terrestrial planets and another five of unknown classification. The orbital periods involved range from about 1.5 to 19 days. The planets are believed to be tidally locked to TRAPPIST-1, resulting in perpetual day on one hemisphere and perpetual night on the other. Their masses are comparable to that of Earth. Notably, up to four of them reside within the star's habitable zone, where conditions may permit the presence of liquid water and life. This possibility has garnered interest from the scientific community and the public.


 * I feel the topic is suitable for TFA given the interest in the possibile existence of water and life. Sandbh (talk) 06:10, 14 September 2023 (UTC)

Outstanding items from copy-edit
Size and composition First paragraph says:


 * "The planet:star mass ratio of the TRAPPIST-1 system resembles that of the moon:planet ratio of the Solar System's gas giants."

I don't understand what this means.
 * It means that the ratio of combined planet masses in the TRAPPIST-1 system to the mass of the star is comparable to the typical ratio of combined moon masses to the mass of the planet hosting them in the solar system. There are physical reasons for these ratios to cluster around 1:10000. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * That's not what the article says. Here the comparison is made only to the Solar System's gas giants rather than to all of its planets. Sandbh (talk) 01:40, 31 August 2023 (UTC)
 * Yeah, I misremembered this item, but it seems that the article says it correctly. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)

Resonance and tides Last paragraph, last sentence says:


 * "Tides can also occur in the planetary atmospheres."

I don't understand what this means.
 * Well, tides on Earth occur in the ocean. They also occur in the atmosphere, which also rises and sinks. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * I've added a link to atmospheric tides. Sandbh (talk) 01:40, 31 August 2023 (UTC)

Skies and impact of stellar light

1. The y-axis for the image says "uncompressed, relative to Earth". What does this mean?
 * It means that the density doesn't account for gravitational compression. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * Added a footnote to the image caption. Sandbh (talk) 01:40, 31 August 2023 (UTC)
 * And sourced it. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)

2. The accompanying paragraph says, in part:


 * "...observers on TRAPPIST-1e, f and g, however, could never experience a total stellar eclipse."

Why not?
 * I think it means that the inner planets can never cover the entire disk of TRAPPIST-1 from the vantage point of these planets. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * That's rather good. Added a footnote. Sandbh (talk) 01:40, 31 August 2023 (UTC)
 * And sourced it. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)

3. The later parts of the paragraph are written as if the T-1 planets have atmospheres while elsewhere in the article it says that it is not known if the planets have atmospheres.
 * Clarified that it's under the assumption of an atmosphere. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)

Moons

"Roche limit" and "Hill radius" could do with short explanatory notes.
 * Done. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)

Formation history

1. What are "Resonant chains"?
 * Chains of planets in resonance. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * Clarified. Sandbh (talk) 01:40, 31 August 2023 (UTC)

2. "protoplanetary" could do with a short explanatory note.
 * Explained. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)

Potential planetary atmospheres

Says in part:


 * "The visibility of an exoplanet and of its atmosphere scale with the inverse square of the radius of its host star."

Does this mean that the visibility is the same for each planet?
 * Probably not, but from Earth the difference in distance between Trappist-1b and Trappist-1g is negligible. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * Now I get it. Clarified. Sandbh (talk) 01:40, 31 August 2023 (UTC)
 * Sorry, but I don't want an unsourced footnote for this. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)

Stability

In the last paragraph what is "XUV" radiation?
 * See the "habitable zone" paragraph. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * Got it. Sandbh (talk) 01:40, 31 August 2023 (UTC)

Possible life

1. Bullet 1 says in part:


 * "Due to multiple interactions, TRAPPIST-1 planets are expected to have intense tides. If oceans are present, the tides could...

The first sentence and the second are dissonant.
 * Not sure what you mean. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * The first sentence is written as it T1 planets are expected to have intense tides. The second sentence seems to contradict this since rather than tides being "expected" not they are only a 50:50 change ("if"). Sandbh (talk) 01:40, 31 August 2023 (UTC)
 * Tides occur on land as well. Added a footnote. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)

2. Bullet 3 refers to microorganisms "ripped". What does this mean? Sandbh (talk) 02:08, 29 August 2023 (UTC)
 * It means that things like meteorite impacts can break off rocks from planets at a sufficient speed that they escape its gravity. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)


 * Clarified. Sandbh (talk) 01:40, 31 August 2023 (UTC)
 * And sourced it. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)

3. Dot point 4 says in part:


 * "...although observations with the Kepler Space Telescope and the Evryscope telescopes indicate the UV flux may be insufficient for both sterilisation and the formation of life."

The way the sentence end does not make sense.
 * Well, the amount of radiation needed to sterilize something is considerably larger than that to create life. What they say is that it wouldn't be enough even to create life. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * Fixed by swapping the terms. Sandbh (talk) 01:40, 31 August 2023 (UTC)
 * That works for me. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)

4. Dot point 5 says in part:


 * "...based on non-organic reduced compounds..."

What are "reduced" compounds?
 * Reducing agent, another not-very-specific explanation is at this source. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * Added a link. Sandbh (talk) 01:40, 31 August 2023 (UTC)

5. The last dot point says:


 * "...may have enough water to completely submerge their surfaces.[292] If so, this would have important effects on the possibility of life developing on the planets, and on their climates."

What effects?
 * Lack of continents that can be eroded by rain, or where non-floating organisms can nevertheless stay exposed to the atmosphere. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * Added a note about the impact on life developing. I could not see anything in the abstract for Guimond, Rudge1 and Shorttle that explains the impact on climates. Could you add a footnote about whatever this is? Sandbh (talk) 05:28, 31 August 2023 (UTC)
 * Found a source that can be used. Note that the verbose "as well as" is necessary here - the CO2 buildup is not a consequence of the nutrient limitation. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)

Scientific importance

1. "TRAPPIST-1 planets[316][317] are considered an important observation target for the James Webb Space Telescope (JWST)[bd][225] and other telescopes under construction."

Why "important"?
 * Because they are so close and there are so many potentially habitable planets. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * Footnote added. Sandbh (talk) 02:25, 31 August 2023 (UTC)
 * Sorry, but that was my assumption, not something sourced that we can simply add to the article. To be honest, I don't remember any discussion in papers about why these planets are so important. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)

2 "...difficulties inhabitants of the planets would encounter with interstellar travel[324] and with their discovering the law of gravitation.[325]"

The law of gravitation was put forward in 1687?
 * Yes, in the solar system. What they say is that it would be much more difficult to make the same discovery in the TRAPPIST-1 system. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * I see. Adjusted the wording. Sandbh (talk) 02:25, 31 August 2023 (UTC)

Notes

"The Hubble time, which is slightly longer than the current age of the Universe."

eh?
 * I am as confused as you are... Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * I've trimmed the footnote as it doesn't really add anything. Sandbh (talk) 02:25, 31 August 2023 (UTC)
 * I've restored, mostly because otherwise people will wonder what "significant time" means. In fact, I am sure I added it because someone asked. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)

Sources

Is it necessary to record all of the authors rather than using "et al."? For example:


 * "Airapetian, V. S.; Barnes, R.; Cohen, O.; Collinson, G. A.; Danchi, W. C.; Dong, C. F.; Del Genio, A. D.; France, K.; Garcia-Sage, K.; Glocer, A.; Gopalswamy, N.; Grenfell, J. L.; Gronoff, G.; Güdel, M.; Herbst, K.; Henning, W. G.; Jackman, C. H.; Jin, M.; Johnstone, C. P.; Kaltenegger, L.; Kay, C. D.; Kobayashi, K.; Kuang, W.; Li, G.; Lynch, B. J.; Lüftinger, T.; Luhmann, J. G.; Maehara, H.; Mlynczak, M. G.; Notsu, Y.; Osten, R. A.; Ramirez, R. M.; Rugheimer, S.; Scheucher, M.; Schlieder, J. E.; Shibata, K.; Sousa-Silva, C.; Stamenković, V.; Strangeway, R. J.; Usmanov, A. V.; Vergados, P.; Verkhoglyadova, O. P.; Vidotto, A. A.; Voytek, M.; Way, M. J.; Zank, G. P.; Yamashiki, Y. (April 2020). "Impact of space weather on climate and habitability of terrestrial-type exoplanets". International Journal of Astrobiology. 19 (2): 136–194. arXiv:1905.05093. Bibcode:2020IJAsB..19..136A. doi:10.1017/S1473550419000132. ISSN 1475-3006. S2CID 152282234."

Sandbh (talk) 02:22, 29 August 2023 (UTC)
 * In the reference section, yes. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)

Sandbh (talk) 05:28, 31 August 2023 (UTC)

English version?

Sometime words are spelt using e.g "-ise"; at other times "-ize". Which English version is applicable for this article? Sandbh (talk) 04:24, 29 August 2023 (UTC)
 * BrEng if possible. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * Done. Sandbh (talk) 05:28, 31 August 2023 (UTC)

'''Distances from T-1?

Is there a reason why these were not included in the property tables? Sandbh (talk) 04:44, 29 August 2023 (UTC)
 * They are - "semi-major axis". Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * Added "= distance" to the note. Sandbh (talk) 05:28, 31 August 2023 (UTC)

The TRAPPIST-1 system with distances to scale

What does this image actually show? It appears to show Earth and its moon, are proportionately close to its sun whereas the T1 planets are further out, whereas we know the T1 planets are much closer to their star than Mercury is to the Sun. Sandbh (talk) 04:48, 29 August 2023 (UTC)
 * Yes, but Mercury-Sun is considerably larger than Earth-Moon. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)

I still don't get it. Sandbh (talk) 05:42, 31 August 2023 (UTC)
 * Sorry, should have been clearer - the image shows the distances, using Earth-Moon as a comparator. The distance between the Sun and Mercury has nothing to do with this. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)
 * OK, still a mystery. It appears to show the Earth and Moon, are proportionately close to the Sun whereas the T1 planets are further out, whereas we know the T1 planets are much closer to their star than Mercury is to the Sun. Hence they should all be shown as being inside the orbit of the Earth. Sandbh (talk) 07:12, 1 September 2023 (UTC)
 * I am positively certain that way more readers know/care about the Earth and Moon than about Mercury. The image compares the Earth-Moon distance to distance scales in the TRAPPIST-1 system; Mercury or the Sun aren't the issue here. I've slightly rewritten the caption to make it clearer. Jo-Jo Eumerus (talk) 07:27, 1 September 2023 (UTC)

Sources

1. Is there a reason why these sources do not have page numbers(?):


 * Burgasser & Mamajek 2017.
 * Brown 2021.
 * MagLab 2022.
 * Agol et al. 2021.
 * Lingam & Loeb 2018c.
 * Not all of these sources have multiple pages. For Agol et al 2021 it's because the info is drawn from multiple tables. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)

Brown 2021 has 20 pages; Agol et al. has 38. For Agol et al, if the info is drawn from multiple tables the the page numbers should be included. Sandbh (talk) 05:28, 31 August 2023 (UTC)
 * That's because Brown 2021 isn't the actual source; it's the paper attached to the database that is the actual source. That's why the cite template is followed by a database link in the sources section. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)
 * This is quite confusing. There are two superficially identical sfn citations: Brown 2021; and Brown 2021. They are both incorrect given they lack "et al.". The first sfn seemingly should not be to Brown et al. but rather to the Gaia3 early release catalog. The second one is to the actual article by Brown et al. and this is OK. The full source listing for the first one looks like it should be...


 * European Space Agency. (2021). Gaia Early Data Release 3 (EDR3). ESA Gaia Archive. Retrieved 1 September 2023.


 * ...or equvialent. Sandbh (talk) 08:03, 1 September 2023 (UTC)
 * Done. Someone might also want to go into Template:Cite Gaia DR3 and fix it. Jo-Jo Eumerus (talk) 08:29, 1 September 2023 (UTC)

2. What is the meaning of the "c" after 2018? Sandbh (talk) 04:58, 29 August 2023 (UTC)
 * It means that there are multiple Lingam & Loeb 2018 sources and we need to distinguish. Jo-Jo Eumerus (talk) 10:05, 29 August 2023 (UTC)
 * Tx. Sandbh (talk) 05:28, 31 August 2023 (UTC)

Items outstanding on this page
Four, in the following sections:
 * Size and composition
 * Possible life
 * The TRAPPIST-1 system with distances to scale
 * Sources Sandbh (talk) 05:51, 31 August 2023 (UTC)
 * Unless I happen to see anything else I believe you're four items away from an FA. Sandbh (talk) 06:44, 31 August 2023 (UTC)
 * I've handled some items, but there are some footnotes that were IMO unnecessary and in any case unsourced which I've taken out. Jo-Jo Eumerus (talk) 09:11, 31 August 2023 (UTC)

Newly introduced errors
08:15 August 31. This edit added the following efn which makes no sense:


 * The Hubble time, which is slightly longer than the current age of the Universe."

The same edit, for no good reason, replaced "sfn|Martínez-Rodríguez|Caballero|Cifuentes|Piro|2019|pp=6, 8" with:


 * "sfn|Martínez-Rodríguez|Caballero|Cifuentes|Piro|2019|p=6.sfn|Martínez-Rodríguez|Caballero|Cifuentes|Piro|2019|p=8"

In fact the efn template specifically accommmodates "pp.".

08:31 August 31. Removed this efn:


 * "Due to a lack of continents that can be eroded by rain, or where non-floating organisms can nevertheless stay exposed to the atmosphere."

So there is once again no explanation of what the basis is for the important effects mentioned in the prior sentence namely, "If so, this would have important effects on the possibility of life developing on the planets..."

08:33 August 31. Removed this efn:


 * "Given they are relatively close and there appear to be several potentially habitable planets."

So there is once again no explanation for the basis of the prior sentence namely, "TRAPPIST-1 planets are considered an important observation target. --- Sandbh (talk) 13:30, 1 September 2023 (UTC)
 * Found a sourceable statement and added it to the footnote. Jo-Jo Eumerus (talk) 16:14, 1 September 2023 (UTC)


 * Yeah, we can't add OR footnotes to FA, especially since a potential explanation is just two sentences before JWST. Without a source, that explanation can't stand. For the erosion thing, I've added a sentence explaining. For the Hubble thing, we need to define "significant time", hence the footnote. JoJo Eumerus mobile (main talk) 14:16, 1 September 2023 (UTC)
 * Nevermind, found a sourceable statement. And merged the Hubble time footnote, but I don't get the issue with the new explanation for the tides. Jo-Jo Eumerus (talk) 16:14, 1 September 2023 (UTC)