Talk:Proxima Centauri b/Archive 1

Caption on image
seems to have thought that this edit is WP:OR. I disagree, as the announcement regarding the planet states that it is probably tidally locked (the orbital distance is key of this) and hence a sunset from the center of the day side would be impossible. However, an eternal sunset would be visible on the terminator line because it is between the day and night side. Therefore, the caption added by is relevant. --MarioProtIV (talk/contribs) 19:26, 24 August 2016 (UTC)

Please add a relevant source. This could be a Venus like planet with no sunset visible from the surface. Don't add it again before consensus Quantanew (talk) 19:30, 24 August 2016 (UTC)
 * Whether the sunset is visible is irrelevant; Prox b is tidelocked; the sun literally does not set. Ergo, no sunset.  Serendi pod ous  19:44, 24 August 2016 (UTC)
 * Tidally locked does not necessarily equal synchronous rotation specifically, it could be in a resonance; see Mercury. ChiZeroOne (talk) 19:55, 24 August 2016 (UTC)
 * In fact the team have released thermal simulations based on either the 3:2 resonance or synchronous rotation . ChiZeroOne (talk) 19:59, 24 August 2016 (UTC) & ref-repair attempted by Jerzy•t 07:40 -49, 25 August 2016 (UTC)


 * Fair enough. Learn something new every day. Added clarifying info.  Serendi pod ous  21:25, 24 August 2016 (UTC)

"Caption on image" Refs
(Sorry, either the ref is broken, or i can't find the right argument to make the s just above work right.) --Jerzy•t 08:35, 26 August 2016 (UTC)

Designation and article title
The discoverers designated the planet Proxima b, not Proxima Centauri b. The article should have the former as the title. Cuddlyopedia (talk) 20:07, 24 August 2016 (UTC)
 * No, it's called Proxima Centauri b, as per all other exoplanets. The use of "Proxima b" is just shorthand.  Serendi pod ous  21:04, 24 August 2016 (UTC)
 * That's what I thought initially too, but it does actually appear that they are calling it Proxima b. None of the literature from the team, including the paper itself, uses the full title 'Proxima Centauri b', only 'Proxima b'. Technically speaking they can give it any designation they like since it hasn't been named by the IAU yet. Even a preprint just made available from the MOST team discussing their observations of Proxima Centauri refer to the planet only as Proxima b . ChiZeroOne (talk) 21:19, 24 August 2016 (UTC)
 * It doesn't matter what the scientists call it; only the IAU has the authority to name astronomical objects. Unless Proxima Centauri's name is changed to Proxima (a change I would welcome, for the record) then that is its planet's name.  Serendi pod ous  21:24, 24 August 2016 (UTC)
 * I'm sorry but that is not true, the scientific designation is purely a convention and is up to the discovery team. http://www.iau.org/public/themes/naming_exoplanets/ ChiZeroOne (talk) 21:34, 24 August 2016 (UTC)
 * I see nothing in that article that suggests that the IAU doesn't need to confirm a name before it becomes official. The IAU is the authority in naming astronomical objects. Whatever or however they are named, the IAU still has to confirm it.  Serendi pod ous  21:47, 24 August 2016 (UTC)
 * What does "The IAU does not consider itself as having a monopoly on the naming of celestial objects — anyone can in theory adopt names the way they choose." mean then?! There is an important distinction between a scientifc designation for an object (like Kepler 1-b) and a name. I was part of the Planet Hunters group and I assure you we never had to ask the IAU to designate our discoveries like PH1b. Indeed that's precisely why that planet has multiple designations, as the Kepler team eventually added their own designation.  The IAU has no involvement in the designation, it is a convention that astronomers have as a group arrived at which why the article describes the various types of designation rather than states any rule. In fact even if you believe it is a rule (which it isn't), since Proxima is an abbreviation it perfectly fits with their description;


 * "The scientific nomenclature for the designations of exoplanets usually consists of two elements: 1) a proper noun or abbreviation, sometimes with associated numbers 2) followed by a lowercase letter."


 * Now this is distinct from proper naming. In fact the IAU refused to get involved until recently in proper naming (and as per my first line technically anyone can still call them what they want), it only did so for public naming competitions because of the Uwingo.com controversy, http://www.iau.org/science/scientific_bodies/working_groups/209/, but does not stretch to overwriting the scientific designations given by the discoverers. "It is understood that, if a scientific designation for the object(s) already exists, the public name will not replace it, but will be recognized by the IAU as the appropriate publicly used name for the object(s)...". ChiZeroOne (talk) 22:36, 24 August 2016 (UTC)


 * There's two options: You can either follow the IAU rules or not. If not, then the discoverers can call the planet anything they like, and they called it Proxima b. If following IAU rules then it's important to note that the IAU (if not other elements of the astronomical community) maintains a clear distinction between names and designations. Few exoplanets have IAU approved names; those that do don't have any of the form XXX b etc. Anything following the format XXX b is not - to the IAU - a name, it's a designation. Designations are entries in catalogues. The Sun's nearest stellar neighbour has many designations (Alpha Centauri C, GJ 551, HIP 70890, etc), but it has only one IAU approved name: Proxima Centauri. Strictly, exoplanet designations should be formed by taking a catalogue designation and appending a b, c, etc. You shouldn't really use a star's name for that purpose, but the IAU sanctions it as an informal usage. But, as it's informal, there's no hard and fast rule, so the planet could be informally referred to as either Proxima Centauri b or Proxima b, and the discoverers chose the latter. Therefore, that should be the name of the article; we shouldn't elevate our own choice above theirs. Cuddlyopedia (talk) 01:13, 25 August 2016 (UTC)
 * To avoid conversations like this, Wikipedia follows IAU rules, even when an alternative would be preferable; hence Tabby's Star is still called KIC 8462852 and Osiris is still called HD 209458 b. So, if we're following IAU rules, what do we call this thing? Alpha Centauri Cb?  Serendi pod ous  04:56, 25 August 2016 (UTC)
 * There are no such rules on scientific designations, reference them if you believe there are.ChiZeroOne (talk) 07:57, 25 August 2016 (UTC)
 * "Wikipedia follows IAU rules, even when an alternative would be preferable..." That's not what it says in Naming conventions (astronomical objects). Cuddlyopedia (talk) 08:18, 25 August 2016 (UTC)
 * Well if we go by that, then this entire debate is pointless. The article is called "Proxima Centauri b". End of.  Serendi pod ous  09:54, 25 August 2016 (UTC)
 * Perhaps we should honor the discovery team name. I vote to change it.Quantanew (talk) 18:05, 25 August 2016 (UTC)
 * If we did that, then we should call 51 Pegasi b "Bellerophon", HD 209458 b "Osiris", and KIC 8462852 "Tabby's Star".  Serendi pod ous  07:51, 26 August 2016 (UTC)

By the way, another planet from the same lead discoverer is Kapteyn b, not "Kapteyn's Star b". ChiZeroOne (talk) 08:50, 26 August 2016 (UTC)


 * The alternate name (Proxima b) is already mentioned and referenced in the first line. Case closed. BatteryIncluded (talk) 13:48, 26 August 2016 (UTC)


 * Is there consensus yet? I see 3 votes to change it, 2 for keeping the name.Quantanew (talk) 03:42, 27 August 2016 (UTC)
 * It is not about collecting democratic votes, but use the most common name. The authors specify they are using the shorthand "Proxima" for Proxima Centauri.   It is NOT a different name and it is NOT controversial. That is done. Get over it. BatteryIncluded (talk) 14:50, 27 August 2016 (UTC)
 * "Proxima b" is the common name, and I have seen no evidence presented that it isn't. The original paper is not saying what you think it is; it never once mentions "Proxima Centauri b", all it says is that instead of refering to it as "the planet" all the way through it will be "Proxima b" in the article. Even the NASA article on the discovery says "Proxima b" .ChiZeroOne (talk) 07:29, 28 August 2016 (UTC)
 * Wikipedia is about consensus. So if it's not a different name and is the most common name (multiple news sources and the discovery paper), let's change it to Proxima b and the consensus is leaning to change it. And the Kapteyn b example is on point.Quantanew (talk) 21:42, 27 August 2016 (UTC)
 * Consensus is determined by the quality of the arguments, not by numbers, and even so, consensus on one page cannot override the consensus of the community as a whole, and the consensus of the community as a whole, as determined by Naming conventions (astronomical objects), is that this article should be called Proxima Centauri b.  Serendi pod ous  21:43, 27 August 2016 (UTC)
 * The naming convention is to prefentially use the common name, and "Proxima b" quite clearly is the common name. ChiZeroOne (talk) 07:32, 28 August 2016 (UTC)
 * For second time, the shorthand name is already mentioned, and it does not supersede the actual naming convention and WP consensus. You are the only one stuck in this position. Relax. Research a worthy topic. Thx. BatteryIncluded (talk) 00:41, 28 August 2016 (UTC)
 * I'm not sure who you are telling to go off and do something else. I see several people (Quantanew, ChiZeroOne, Cuddlyopedia) agitating to change the article name, which would be inappropriate. Are you telling Serendipodous to shut up and let them change the name? Tarl N.  ( discuss ) 04:15, 28 August 2016 (UTC)
 * I think he's saying that to Quantanew. —MartinZ02 (talk) 07:00, 28 August 2016 (UTC)


 * Yes, to Quantanview and ChiZeroOne, again please note the full name in the title and the short-hand name used in the introduction:
 * The habitability of Proxima Centauri b - II. Possible climates and observability.
 * Cheers, BatteryIncluded (talk) 22:25, 28 August 2016 (UTC)
 * Cheers, BatteryIncluded (talk) 22:25, 28 August 2016 (UTC)

ESO paper copy
I notice the article is currently referencing Nature where the full article is under paywall, but as an open publisher shouldn't we really reference the full article provided by ESO? http://www.eso.org/public/archives/releases/sciencepapers/eso1629/eso1629a.pdf ChiZeroOne (talk) 20:15, 24 August 2016 (UTC)

True added Quantanew (talk) 20:29, 24 August 2016 (UTC)

Wiki Sky coordinates
Can someone help me fix the coordinates on the wiki sky link? It doesn't link to anything Quantanew (talk) 20:32, 24 August 2016 (UTC)

Mass range
I don't agree with the note created in this edit by MarioProtIV (thanks for your work on the article in general btw). The fact that there is a significant chance that the real mass is 2 or even 3 solar masses is very important, not minor additional information. If we just give the minimum mass, many readers may have no idea about the related probability distribution and just assume that the real mass is near 1.3 solar masses. Gap9551 (talk) 22:19, 24 August 2016 (UTC)
 * I find the figures as they are represented problematic too to be honest. The radius has not been measured; it is an estimated quantity based on a model using a poorly constrained quantity as an input. I have a problem with it being represented, especially in the infobox, without making clear that it is only an estimate and the specific assumptions being made.  To include errors without explanation of what they mean is particularly misleading since they are only appropriate for the mass selected to apply to the mass-radius relationship model used.  I think the least misleading thing to do considering the multitude of assumptions would be to remove it from the infobox. ChiZeroOne (talk) 23:12, 24 August 2016 (UTC)
 * I totally agree. The Planetary Habitability Laboratory source even states: The mass of Proxima b suggests a rocky composition, but we do not know its radius to evaluate its bulk density. Both mass and density are unknown, and even assuming rocky composition, there is still a range of possible densities. I'll remove the figure from the infobox (no context) and be more clear about the prose. Gap9551 (talk) 23:37, 24 August 2016 (UTC)
 * Writing "The actual mass depends on the unknown orbital inclination..." is gross negligence. In fact, the actual mass is a definite but unknown quantity, and its "depending" on anything else is only a metaphor for our ignorance of the definite quantity; the interesting thing depending on "the unknown orbital inclination" is not that mass, but an array of degrees of embarrassment that could result from taking seriously the various nearly certainly wrong estimates that leaving us to guess about -- or rather, stated probably more justly, concealing from us -- the presumably many-times-larger #s that the next 9% tranche of possible o.i. values produce. --Jerzy•t 06:25, 25 August 2016 (UTC)
 * I presume if there were an upper limit, that would be stated, and thus that the only upper limit is a mass that would make the planet's rotation shift the (so much more observable) star back and forth. Readers deserve more info, including the 99% figure, which BTW will, my guess is, shock our pants off. Thus i'm about to replace the sent in question with
 * The mass of Proxima Centauri b cannot be measured, but an established astronomical procedure does guarantee that its mass is no less than, and when its orbital inclination is known, the mass can be calculated. 90% of possible orientations would imply a mass below.
 * I can imagine that discussions of "actual mass" as a variable quantity appearing in the formulas for setting probabilistic limits on mass are reasonable in text books and perhaps tech papers, but 'pedia readers come to WP or any non-professional 'pedia for better decoded info than what i found. --Jerzy•t 07:01, 25 August 2016 (UTC)
 * I did some OR for our own perspective, and I find a mass of for 50% chance of being below that (the median mass),  for 90% (the  we cite is rounded),  for 95%,  for 99%,  for 99.9%,  for 99.99%,  (0.9 Jupiter mass) for 99.999%,  for 99.9999%, etc. Gap9551 (talk) 22:36, 25 August 2016 (UTC)
 * Not as bad as i feared it might be (but i'm pleased that i was right in guessing that to 1st order we're sure of nothing). I suspect many readers would be surprised that the 90% fig is nowhere close to being an upper limit, and i wonder if it might worth a rough log-log plot of %-doubt vs. mass data the relationship your data implies between size-upper-limit and probability of exceeding a given size. --Jerzy•t 06:53 & 07:25, 26 August 2016 (UTC)


 * I made such a plot, added on the right. Whether it (or a better version) can be used in the article is a matter of consensus per WP:CALC. Data used are the minimum mass and stellar mass (both cited in the article), the binary mass function, and a basic geometrical relation between inclination and probability. Gap9551 (talk) 19:43, 26 August 2016 (UTC)


 * What about adding a ≥ on the radius in the infobox to assure that the radius could be larger then what PHL estimates in its catalog? I could do the same for Gliese 667 Cc. --MarioProtIV (talk/contribs) 15:49, 25 August 2016 (UTC)
 * On reflection, and bearing in mind that the infobox can't be expected to work if jammed full of everything the article has room to say, i like, for the infobox either Mario's suggestion of "≥ [etc.]", or that followed by "; <, with 99% certainty". (Not to the exclusion more detail in the text, where space and attention come a lot cheaper.)   Thanks to Gap for calcs i long ago forgot how to do (even if i could tease out the geometry & trig that the model requires!)   (It's hard to say which error probability is most appropriate for such an article, and IMO the answer depends on how much gravity is too much for colonization, and on both what the odds of reaching destination, and the very different odds of round trip, are; there're some tempting hard-SF plots lurking in this article!) --Jerzy•t 08:16, 26 August 2016 (UTC)


 * I am a bit surprised that the cited mass is almost everywhere, where this is only the lower limit. I would expect the 50% figure, i.e., to be cited most of the time. Regards, Yann (talk) 11:47, 27 August 2016 (UTC)
 * Hey, "it's morning again in America" again; welcome back to the Dark Ages! --Jerzy•t 09:25, 29 August 2016 (UTC)

Flaw in free image
Phil Plait at Slate.com says that Proxima Centauri would be much larger in the sky of the planet than our Sun is in our sky. It must be, because since Proxima Centauri is so dim, a planet must be much closer to it to be in the habitable zone. If possible, could another image be made or found? Abductive (reasoning) 02:18, 25 August 2016 (UTC)
 * How can you be sure that the angular size of the star in the picture is wrong? It depends on the angle of view of the picture itself, which depends on the lens. Gap9551 (talk) 03:48, 25 August 2016 (UTC)
 * The point of an artist's conception is to represent the item as best as possible, not to rely on fanciful explanations about lenses and other remote possibilities. Abductive  (reasoning) 23:30, 25 August 2016 (UTC)
 * I just don't know what is wrong with the picture, but maybe someone else can help you better. Gap9551 (talk) 23:47, 25 August 2016 (UTC)
 * What Gap9551 says is true, and it's not just some "fanciful explanations about lenses". Basically, he's trying to tell you that it's impossible to tell how big the star is because it depends on the angle of view (and if you don't know what that is, you can just read the Wikipedia‐article). —MartinZ02 (talk) 18:06, 26 August 2016 (UTC)


 * An angular size comparison is in the gallery.Quantanew (talk) 03:47, 27 August 2016 (UTC)
 * Your explanation(s) are as weak as bathwater and are based on the fact that you can't find any other free images, not on science. Abductive  (reasoning) 07:20, 27 August 2016 (UTC)
 * Why would I (or anyone) try to defend an image just because "[we] can't find any other free images"? I'm just trying to tell you that it's impossoble to tell if it appears larger then the Sun or not. —MartinZ02 (talk) 12:40, 27 August 2016 (UTC)
 * Abductive, your argument seems to be based on a faulty premise. And please refrain from personal attacks. Ashmoo (talk) 12:01, 30 August 2016 (UTC)

Habitability
The article mentions "The planet has an equilibrium temperature of 234 K (−39 °C; −38 °F)." Isn't that a little cold for it being habitable? Granted, it mentions further down that points on the surface could be warmer, maybe even allow liquid water, but calling it "habitable" is, IMHO, far-fetched. Maybe a new market for | Canada Goose or | Kanuk? — Preceding unsigned comment added by CielProfond (talk • contribs) 12:15, 25 August 2016 (UTC)
 * The clue is in the fact it specifically states the equilibrium temperature rather than surface temperature. We cannot currently measure the true surface temperature, and any model of the surface temperature relies on a lot of assumptions. The safest estimate we can state is the model of temperature with the fewest assumptions. The equilibrium temperature is a simplistic model of the temperature of body that reflects a certain fraction of the energy it recieves from its star, that's all there is too it. For comparison the equilibrium temperature of the Earth is -20°C  The reason you are not frozen solid is primarily due to the fact the Earth has an atmosphere, something not modelled in the equilibrium temperature. The gases within it trap heat near the surface, raising the temperature. We don't now if this planet has an atmosphere (it probably has some kind of atmosphere, but we don't actually know for certain) but if it does then it too will have some greenhouse effect.  So planets with warm equilibrium temps probably aren't 'habitable', because once you add in the atmosphere surface temperatures would soar. ChiZeroOne (talk) 12:58, 25 August 2016 (UTC)


 * That judgment also depends on whether there is an atmosphere and or a large body of water. Kortoso (talk) 17:32, 25 August 2016 (UTC)
 * And a strong magnetic field, chemical precursors, gravity, energy gradient, etc... -Cheers, BatteryIncluded (talk) 00:56, 26 August 2016 (UTC)

It would be great to have a copy of. Regards, Yann (talk) 17:46, 26 August 2016 (UTC)

As of 2020/01/28 our article said that Prox Cen b "is unlikely to be habitable," with three citations. However I propose that more neutral text should be used, since none of these citations are definitive. One is based on just a BBC author's claim that "Just how "habitable" this particular planet really is, one has to say is pure speculation for the time being," which is agnostic as to habitability. A second is an opinion piece in Science that states "many [exoplanets] appear to be far better candidates for hosting life than the one around Proxima Centauri," which again is not the same as claiming Prox Cen b couldn't be habitable. The last and most definitive is a scientific article by Ribas et al., who write "We conclude that Proxima b is a viable candidate habitable planet." I therefore changed the article text to the more neutral "the habitability of Proxima Centauri b has not yet been definitively established." — Preceding unsigned comment added by Kreuzfeld (talk • contribs) 15:29, 28 January 2020 (UTC)

Light from α Cen AB?
The binary system at Alpha centauri are not far away from Proxima and their total light output is about twice that of our sun. How much illumination would this binary star provide at the surface of Proxima b? Kortoso (talk) 17:35, 25 August 2016 (UTC)
 * The luminosity of the binary is about (1.519+0.445)/0.00155 = 1260 times that of Proxima Centauri, and the distance between the binary and Proxima Centauri is 15,000 AU, about 15,000/0.05 = 300,000 times further away (using figures from the lead of Alpha Centauri. The flux from the binary is 1260/(300,000)^2 = 1.4e-8 times lower than Proxima, or 70 million times lower. Gap9551 (talk) 18:36, 25 August 2016 (UTC)
 * Otherwise phrased, the Alpha Centauri binary is 273k AU from earth. Proxima is 15k au from Alpha, 18 times closer. That means Proxima will see the Alpha binary as 331 times brighter than we do, or shining at about magnitude -6.3. That's brighter than Venus at its best (magnitude -4.4), but not as bright as the full moon (magnitude -12.6). However, the pair should be easily resolvable by a naked eye into two separate stars at that distance. Tarl N.  ( discuss ) 19:29, 25 August 2016 (UTC)
 * Cool, thanks! Kortoso (talk) 19:33, 25 August 2016 (UTC)
 * That's an interesting information. It should be added somewhere. In the "Host star" section? Regards, Yann (talk) 11:56, 27 August 2016 (UTC)
 * It's WP:OR. I have the envelope right here where I scribbled the numbers. It's easily derived information, but until someone publishes an article to that effect, it doesn't belong outside the talk page. Tarl N.  ( discuss ) 15:18, 27 August 2016 (UTC)
 * Tarl_N.: IMHO, it is an abusive interpretation of WP:OR not mentioning "about magnitude -6.3". It is a simple calculation. Now, I agree that interpretation of this number would be OR, but that a different thing. I also wonder if Alpha Cen (AB) would be visible in day light, as Proxima is mainly infrared radiation, and Alpha Cen (AB) is not. Regards, Yann (talk) 10:46, 28 August 2016 (UTC)
 * For humans, depending on the atmosphere, the stars would be visible in daylight (you can see Venus on a clear day, at two magnitudes dimmer, if you know where to look). Note that Proxima, at 3000 K, is not particularly dark or even tremendously red; that's the same temperature and blackbody radiation you get with an incandescent light bulb. It looks red only in comparison to stars at higher temperature. The peak emission is indeed in infrared, but it's not that dramatic a curve - it's fairly flat, you still get blue and green wavelengths. Tarl N.  ( discuss ) 13:30, 28 August 2016 (UTC)

I agree that the apparent magnitude of Alpha Centauri AB from Proxima is a simple enough calculation to include. The apparent angular separation of A and B is a bit trickier. Assuming the orbit is face on, at apoastron it's 35.6/15000 = 2.37 miliradian = 8.16 arc minutes. At periastron it's 11.2/15000 = 0.747 mr = 2.57 arc min. For comparison, Mizar and Alcor, considered a good acuity test for humans, have a separation of 14.4 arc seconds. But what one would see From Proxima b depends on the orientation of the AB orbit. We have accurate parameters relative to a line of sight from Earth. See Parallax and masses of α Centauri revisited⋆ Dimitri Pourbaix1,⋆⋆ and Henri M. J. Boffin for more recent data. It should be possible to compute the inclination and argument of periastron as seen from Proxima b. Has anyone done this? One could imagine beings on Proxima b using the relative positions of A and B to create an 80 year calendar. Also given parallaxes are known to better than 0.2% it should be possible to refine the 15,000 au distance value.--agr (talk) 13:05, 28 August 2016 (UTC)
 * I just noticed that our Alpha Centauri article already has a paragraph on what AB looks like from Proxima. It's been there at least a year. I added a subhead to the paragraph Alpha Centauri. We could link to it from this article or copy the text, with its footnote.--agr (talk) 22:39, 28 August 2016 (UTC)

Short or long scale
Some info is said as "billion", "trillion" etc. OK, is it long or short scale? As scientific article shd it use 109, 1012 instead to avoid misunderstandings?--RicHard-59 (talk) 20:07, 25 August 2016 (UTC)
 * I think that's only necessary once we get to quadrillion and beyond that. --MarioProtIV (talk/contribs) 20:58, 25 August 2016 (UTC)
 * Short scale is used in the article. Is the long scale still used in the English language in certain regions? Gap9551 (talk) 21:07, 25 August 2016 (UTC)
 * Short scale is frequently used around America/the world, the long scale isn't really used as much as it used to. --MarioProtIV (talk/contribs) 22:06, 25 August 2016 (UTC)
 * Even Nature, a British publication, has formally given up on long scale. Billion is 109. Tarl N.  ( discuss ) 01:48, 26 August 2016 (UTC)
 * Hey, folks, look what i found! There's an article on WP called "Long and short scales" where all the info needed for this particular talk section is supposedly on tap. And if you use this cool formatting
 * Long and short scales
 * everyone can link right to the details! --Jerzy•t 08:29, 26 August 2016 (UTC)
 * So this is not a Scientific article that should use Scientific notation?--RicHard-59 (talk) 09:10, 26 August 2016 (UTC)
 * Scientific notation is not required for an article to be scientific. Using 'billion' etc probably makes it more accessible for a general audience. Also, 40 trillion is similar to $40$ at least in the sense that the number of significant digits is the same, which is what really matters. Gap9551 (talk) 18:31, 26 August 2016 (UTC)
 * Amen, scientific notation is crucial for keeping your head straight when you do calculations in your head, and until you've written them down enuf times to be sure you've educated your gut about the magnitudes of the phenomena. It's pretty much a supplement, or just rude, unless you're writing just for specialists in the topic. We probably should have a guideline that says this. (So we probably do!) --Jerzy•t 09:38, 29 August 2016 (UTC)

Tidal heating
Hi, It would be interesting to mention how much tidal heating is generated, and the possible effects on the planet environment (i.e. see Io (moon)). Regards, Yann (talk) 12:00, 27 August 2016 (UTC)
 * Tidal heating would be dependent on orbit eccentricity. If the orbit is perfectly circular, there would be no tidal heating. We simply don't know at this stage. Tarl N.  ( discuss ) 15:16, 27 August 2016 (UTC)
 * Make that read "If the orbit were perfectly circular, and the planet kept the same face to the star, and its axis were perpendicular to the plane of its orbit ... so in practice, there's tidal heating unless its an artificial planet and the question is how much." --Jerzy•t 09:56, 29 August 2016 (UTC)

On top of that... If, Proxima b was rotating every 7.5 days, any oceans on that planet would have a tidal range greater than 2000 feet! — Preceding unsigned comment added by 86.148.108.53 (talk) 04:23, 21 September 2016 (UTC)

Tautology
I have attempted to remove the obvious tautology in "It is the closest known exoplanet to the Solar System as well as the closest potentially habitable one known." but my attempt to improve the style of this article was reverted. Obviously MarioProtIV, who removed my correction would not agree, but does any one else have an opinion?Redcliffe maven (talk) 06:38, 28 August 2016 (UTC)


 * I agree, and I don't understand why your edit was reverted.  TomS TDotO (talk) 13:57, 28 August 2016 (UTC)
 * I did a tweak. Hope it works. -BatteryIncluded
 * I'll note the comment in Nature ( Astronomy: Earth-like planet around Sun's neighbour ) makes a point to use the term "temperate" zone rather than "habitable". Until we understand what makes a planet habitable, it is better to say that Proxima Centauri b lies in a temperate zone (the right temperature) rather than a habitable zone (the right conditions to support life). If nothing else, the X-ray flux by itself probably removes this planet from the "potentially habitable" list, because the extended impact of high-energy radiation would be to strip the atmosphere.


 * I'm so glad someone in Nature news published that. It should be incorporated into this WP article. It is an old item in my To-Do list in Wikipedia to remark and clarify that "planetary habitability" usually and traditionally applies to humans and yes, it desires a temperate climate. For a couple of decades, it now includes any body in outer space that is capable to heat and harbor internal liquid water, where extremophile microorganisms may be able to thrive and reproduce in extreme and dark environments. BatteryIncluded (talk) 20:36, 28 August 2016 (UTC)

Not only did your tweak get undone, we are also treated to "could conceivably be habitable"! I am restraining myself from just removing the entire sentence. Or is there something that can be said? TomS TDotO (talk) 22:57, 28 August 2016 (UTC) TomS TDotO (talk) 22:57, 28 August 2016 (UTC)
 * Unless the planet is definitely judged unhabitable, I don't see how this phrasing of mine is objectionable. --Florian Blaschke (talk) 23:57, 28 August 2016 (UTC)
 * Only if you stretch "conceivably habitable" to become a meaningless statement. What we know about the environment around flare stars pretty much precludes habitability (Hence Nature using that careful terminology). It would take something extraordinary for that planet to still have an atmosphere today - the tremendous X-ray flux almost certainly has stripped any gaseous components away. The planet is probably a mercury-like barren landscape. Tarl N.  ( discuss ) 01:10, 29 August 2016 (UTC)
 * Just about any planet can be conceived as having life. That is the weakest form of possibility. But the statement is not "conceivably inhabited". it is "conceivably possibly". Why not just be straightforward about what you mean, that planet is in the temperature zone for liquid water? And then there still is the tautology which began this discussion. What improvement is there beyond what BatteryIncluded had written?    TomS TDotO (talk) 01:42, 29 August 2016 (UTC)
 * No, not any planet is conceivably habitable in the sense of planetary habitability. A gas planet, for one, is not, even if it is in the temperature zone for liquid water. Also, note that I was not the one to revert the tweak, that was FreeKnowledgeCreator here. What I did here was simply an attempt to make FreeKnowledgeCreator's point "there is at least some reason to think it might be habitable, which is not the case with most planets" in simpler and less stilted (to the point of barely being grammatically correct or intelligible) language. --Florian Blaschke (talk) 02:26, 29 August 2016 (UTC)
 * FWIW - re "Planetary habitability" and "Gas giants" => please see discussion "Could PH2 b (aka Kepler-86b) Be Potentially Habitable - Or Not?" at the following => https://en.wikipedia.org/wiki/Talk:Kepler-86#habitability - ALSO => seems "Carl Sagan" thought "Life could exist on gas giant planets", "including Jupiter itself". - in any case - hope this helps in some way - Enjoy! :) Drbogdan (talk) 13:05, 29 August 2016 (UTC)
 * True, but planetary habitability primarily refers to a conservative, Earth-centric view of life and environments favourable to it, rather than more exotic possibilities (such as life in a liquid underground ocean depending on heat by volcanic activity on a large moon circling a gas giant). After all, Jupiter is far from the habitable zone, so not habitable in the more conservative sense we are talking about here. --Florian Blaschke (talk) 17:09, 29 August 2016 (UTC)


 * If it is habitable, then say that it is habitable, don't say that it is conceivably habitable. BTW, I am not blaming anyone. All I care about is the text.   TomS TDotO (talk) 02:51, 29 August 2016 (UTC)
 * This seems to be a misunderstanding. With "could conceivably be habitable", I mean "it is conceivable that it could be habitable". I know that habitability always refers to a potential. We all agree that too little is known about the planet to be sure either way.
 * Anyway, maybe the current phrasing is better, although I'm still not entirely happy with it: "hosting life" is a far stronger proposition than merely the potential of hosting life due to favourable conditions. Unless you assume that a planet with favourable conditions is virtually guaranteed to actually host life, which sounds like a rather bold claim to me, and is also contradicted by planetary habitability (quote: "Habitable environments do not need to contain life"). --Florian Blaschke (talk) 17:06, 29 August 2016 (UTC)
 * I just realised that it was Phil Plait who originally wrote "If so, that makes it not just the closest exoplanet known, but the closest potentially habitable one known." In context, the wording is less clunky. We should avoid following his wording too closely anyway. The current wording is fine in any case, so I consider this issue resolved. --Florian Blaschke (talk) 01:47, 3 September 2016 (UTC)

Habitable Zone Discerpancy
The article mentions that the only habitable area of the planet, if it is indeed tidally locked, would be around the terminator zone, yet the atmosphere/temperature simulation videos indicate that temperatures in even the center of the Proxima-facing hemisphere would be no greater that 40° C, a temperature at which water is completely liquid and in which life can flourish. Is either correct, or should the article be reworded to take this into account, given the purely theoretical nature of it all? — Preceding unsigned comment added by 149.84.64.69 (talk) 22:38, 28 August 2016 (UTC)


 * The models use several assumptions, most critically is the existence of water. Regardless of its current temperature and stellar irradiation, the hot evolution of this planet-star system negates any water is left (they admit it), but if a miracle happened and say, ground water was ejected, then they propose several scenarios on the resulting hypothetical atmosphere and climate. Think of it as the Drake Equation, where you just plug in different optimistic values and contemplate the various fictional results. Does this help? BatteryIncluded (talk) 02:17, 29 August 2016 (UTC)

Great work everybody!
Probably not suitable for a TalkPage, but I need to say this. Great. RhinoMind (talk) 03:38, 29 August 2016 (UTC)
 * I (and i expect most of our colleagues) find your contribution in this section exemplary. I don't think we need praise to stay motivated, but if it's not stilted cheerleading, it's almost certainly worth our effort spent reading it. --Jerzy•t 10:03, 29 August 2016 (UTC)
 * Thanks. No my enthusiasm was genuine. I don't think there is anywhere else one can be better generally informed about this new discovery than here. With relevant ref's and links this is a great place to start. Yes, there are some minor flaws and the usual quarrels, but I was suddenly feeling overwhelmed at what the Wikipedian community bring the world. Call me sentimental, I don't care :-) RhinoMind (talk) 19:30, 29 August 2016 (UTC)
 * Thanks for sharing. :) Gap9551 (talk) 19:59, 29 August 2016 (UTC)
 * This is a bit early; couldn't you at least wait for the article to pass the GA review? Whatever, thanks I guess. —MartinZ02 (talk) 20:12, 29 August 2016 (UTC)

Habitability
Found another study of the Habitability if anybody wants to expand. The Habitability of Proxima Centauri b I: Evolutionary Scenarios Quantanew (talk) 04:04, 29 August 2016 (UTC)

Habitability zone as a period
I'm not sure why it's necessary to express the "habitability zone" as a period. The A^2=P^3 means you can express an orbit size in days, but there is no need in this case, nor any particular relevance. Please discuss it *BEFORE* adding again. Tarl N. ( discuss ) 04:35, 29 August 2016 (UTC)
 * By the way, WP:BRD specifies that the sequence is roughly:


 * Do something Bold.
 * Someone reverts.
 * Discuss.
 * This does not mean add something bold and someone has to discuss it to remove it. It means a bold change that is reverted, is discussed before being added again (if it achieves consensus). Tarl N.  ( discuss ) 04:39, 29 August 2016 (UTC)

Habitable zone
To quote from the discovery paper: Habitable zone range [AU] ∼ 0.0423 – 0.0816 and Habitable zone periods [days] ∼ 9.1–24.5.. This keep been reverted by some users, batteryincluded Quantanew (talk) 04:42, 29 August 2016 (UTC)
 * See section directly above. There is no point in adding a period for a habitable zone (really, a temperate zone) in this article. For an astrophysicist, period and semi-major axis are interchangeable and equivalent pieces of data. When analyzing doppler data, the information they will have is the period, the distance is derived. For this article, the applicable information is the distance. There is no need to add the complication of the period for people who don't live and breathe the relationship between an orbit's area traversed vs time. Tarl N.  ( discuss ) 05:17, 29 August 2016 (UTC)
 * The subject of the sentence is the star, not the planet. Stars have no orbital period! Get it Quantanew? BatteryIncluded (talk) 15:24, 29 August 2016 (UTC)


 * First this is an article for the general public, the figure (Habitable zone periods [days] ∼ 9.1–24.5) is more relatable then AU for the general public, nothing of what you just wrote (Tarl N) overrides what the the discovery team says on their paper. Please you think people can't understand orbits?. Both of you are trying to censor a fact backed up by the main source.


 * Where do I say that stars have orbital periods? please show me batteryincluded. That was corrected. I only added what I found on the paper. The subject is the Habitable zone of the star. Get it? Quantanew (talk) 08:22, 31 August 2016 (UTC)


 * Hi Quantanew. Please read what Tarl N has to say above. He explains the problem quite well. I think BatteryIncluded misunderstood the issue too. RhinoMind (talk) 09:33, 31 August 2016 (UTC)
 * What Tarl N is doing is becoming judge of what people can or can not understand. Is B.S. Claming that is too difficult to understand.Quantanew (talk) 18:20, 16 September 2016 (UTC)
 * No, I'm saying there is no point in stating the same information in two different ways, one of which is obvious, the other which is due purely to the form of jargon used by someone observing light curves. The distance is useful, and has meaning outside the limited community that analyzes light curves. The period is easily misconstrued (and I suspect you must be doing so, due to your insistence on its presence), and meaningless outside the specific context of the observational mechanics of that specific star. If you really disagree with me, there are mechanisms for overriding - you could start with WP:3O, getting someone uninvolved to take a look at the dispute. Tarl N.  ( discuss ) 00:15, 17 September 2016 (UTC)

Name - 'b'
I am just a passing amateur, but why would the planet be named 'Proxima Centauri b', not 'Proxima Centauri a'? Is there an expectation of an 'a' closer to the star? Hogweard (talk) 12:52, 31 August 2016 (UTC)


 * There is an article Exoplanet naming convention which will tell you more than you want. Briefly, "a" is reserved for the central star, "b" for the first planet to be discovered, etc. It is not a good idea to name the planets by closeness to the star, as later discoveries are likely to change the order. Order of discovery is the only stable information.  TomS TDotO (talk) 13:21, 31 August 2016 (UTC)


 * Thank you. That makes sense. Hogweard (talk) 17:50, 31 August 2016 (UTC)

Possible original research
New user N Vildmon Borneo just added content which they called "my research". This user has only three edits, all in this article. The user attributed it to sources that already were in the article. It seems questionable. - Alumnum (talk) 11:10, 5 September 2016 (UTC)

An age problem
An age for the parent star PC, is given as 4.85 Gyr in the article with a reference to a peer-reviewed article. The problem is, that the article does not give any estimate of the star's age. The article is concerned with the star's metallicity, which is very difficult to determine for red dwarf stars.

If we supply info about the age of the star, we need a solid ref on it.

Instead of deleting the information, I have inserted a cn-tag. I hope this soft approach would incite interested editors in tracking down a good ref on the age? RhinoMind (talk) 18:23, 5 September 2016 (UTC)
 * You are right, I added another tag although that might be redundant. The age is cited in the prose using this Space.com source, which does not strike me as overly reliable. A paper would be better. Gap9551 (talk) 18:28, 5 September 2016 (UTC)
 * No, you are right, sources from popular science publications are not a good way to build a solid article. Sometimes they gather info from WP too and this would make errors here go viral. RhinoMind (talk) 18:43, 5 September 2016 (UTC)
 * The Proxima Centauri article has an ESO source that I used here now too, it seems more reliable. The paper that the press release links to does not seem to give the 4.85 Gyr figure though. Gap9551 (talk) 18:37, 5 September 2016 (UTC)
 * The ESO on-line source looks quite informative and should suffice I think? Great job. Hopefully we could also get some of the original papers up with time, but not a pressing task I guess. RhinoMind (talk) 18:43, 5 September 2016 (UTC)

I believe the problem has been speedily solved. RhinoMind (talk) 18:45, 5 September 2016 (UTC)

3:2 resonance vs 2:1 resonance
There has been some text that an anonymous IP editor has repeatedly inserted about a 2:1 resonance. The citation he's using is an article about 3:2 resonance, which in 18 pages makes a single reference to "(or maybe a 2:1 resonance)". That is so exceedingly unlikely that none of the article even bothers with it. Please discuss why you want to include this there. Regards Tarl N.  ( discuss ) 17:00, 10 September 2016 (UTC)
 * There is a second reference in the article: "ω ≈ 3n/2 rotation becomes stable for an eccentricity greater than 0.06–0.07, and the ω ≈ 2n above e = 0.16." In other words 2:1 resonance isn't even stable unless the eccentricity exceeds 0.16. It isn't significant enough for the article to bother giving the capture probabilities as done for 3:2 capture. Tarl N.  ( discuss ) 17:11, 10 September 2016 (UTC)
 * Answering one of the edit comments, since the editor isn't discussing them here. The paper cited makes *no* mention of 5:2 resonances. It mentions 3:2 and, in passing, 2:1 simply by saying it requires higher eccentricity (greater than 0.16). We've already ruled out extreme eccentricities for Proxima b (mentioned in that same paper), so the higher resonances aren't even on the table. Tarl N.  ( discuss ) 21:55, 10 September 2016 (UTC)
 * I'm now at WP:3RR, I can't re-revert it again, and User:86.183.214.137 refuses to engage in discussion or do anything beyond simply re-installing his changes. Tarl N.  ( discuss ) 21:45, 10 September 2016 (UTC)

Why does the ESO have a different value for Proxima's habitable zone?
If they really think that b is that close, then they must think it's like Venus.  Serendi pod ous  15:13, 17 September 2016 (UTC)


 * What different value? They state: As a result it lies well within the habitable zone, where liquid water can exist on the planet’s surface. I think you're confusing distance with insolation. Proxima b is so much dimmer than the sun that it has to be much closer to get the same amount of heat from it. Tarl N.  ( discuss ) 15:23, 17 September 2016 (UTC)
 * Wiki's article on Proxima Centauri places its habitable zone at 0.023–0.054 AU, or 3.4 to 8.1 km. That would mean Proxima b, at 0.0485 AU, or 7.26 million km, would be near the outer edge, not the inner one.  Serendi pod ous  15:45, 17 September 2016 (UTC)
 * The report here gives a vastly different estimate for the habitable zone: ∼0.0423 – 0.0816 AU (page 10, based on a more recent reference in the report - #22 "Kopparapu, R. k. et al. The Inner Edge of the Habitable Zone for Synchronously Rotating Planets around Low-mass Stars Using General Circulation Models. Astrophys. J. 819, 84 (2016)."). The main article's value seems to be based on a 2002 source. Just noting the source of this difference - as a layman I can't evaluate either set of values. GermanJoe (talk) 16:35, 17 September 2016 (UTC)

I'll admit I'm mystified where the Wiki number comes from. The citation given (Nature's announcement of Proxima B) states ...0.05 AU, it lies squarely in the centre of the classical habitable zone for Proxima without actually defining the range of the habitable zone. The Nature article, in turn, cites a 2013 Kopparapu article Habitable zones around main-sequence stars: new estimates. which shows how to calculate the zone for planets around stars but does not cite a specific for Proxima. Note that the article specifies that the habitable zone varies tremendously based on assumptions about the planet itself - wet/dry/atmosphere/clouds/greenhouse - so there is probably no one definitive value for a range of habitable zone. I'll also note in response to the earlier question, that the habitable zone for Earth around Sol starts at about 0.99 au, so a planet near the inner edge of a defined habitable zone is not expected to be anything like Venus. Tarl N. ( discuss ) 23:23, 17 September 2016 (UTC)

Current and/or future observations?
Hello. Recently there has been some edits back and forth about a section headline. As I understand the issue, all previous observations has (hopefully) been incorporated into the general article. Because they provide the backbones of our knowledge about Proxima Centauri b. Quatanew has briefly argued that there is a current observation going on and concludes that the section headline should be "Current and future observations" on that ground.

Three things:

1. As I read it, there are only ideas for some future observations going on. No observation project is being carried out at the moment?

2. I am not sure I understand what a "current observation" is actually. Either you has observed something or you plan to observe something. Some astronomical observations though, does have a long exposure time with some lasting a few days. But such a "current observation" would soon turn into a "previous observation", at least in the time-frame we are used to as WP-editors. What does a "current observation" really mean?

3. The purpose of the section is to describe future observations. If it includes observations already made, we have done a bad editorial job at incorporating the knowledge gained from this into the general article.

A small thing perhaps, but I think we should come to some agreement of what the section is all about. RhinoMind (talk) 17:20, 4 October 2016 (UTC)

Radius?
I just restored the removed value for the planet's radius in the infobox, but noticed that the given value is not specified in the source (ref #7). This might be OK for a somewhat simplifying infobox, although an explanatory footnote could be helpful there. However, "If the planet has a rocky composition and a density equal to that of the Earth, then its radius is at least 1.1 R⊕." in the article's body has no direct source for such a specific value, and the source's -probably unlikely- minimum value of 0.8 is not even mentioned. The current handling doesn't seem to be ideal and/or the statement needs different sources. Thoughts or ideas for improvements please? GermanJoe (talk) 02:55, 25 October 2016 (UTC)


 * The radius of this body is still unknown. Its discovery was performed through radial velocity measurements, which yields mass only. Unless and until a series of transit observations is made, the radius remains a matter of conjecture. One may assume that if it is a rocky body, within certain constraints, then a guess at its radius (within a given range) can be made. But I don't personally regard that to be useful information for an encyclopedia.


 * We might even want to make a point of it.:

"While the Doppler method is great for detecting planets, it's not great at telling us anything about them. Scientists can predict the distance of the planet from its host star, they can estimate its orbital period, and they can figure out its minimum mass. That's it. So for now, that's all we know: Proxima b is at least 1.3 times as massive as Earth, it orbits its sun every 11.2 days, and it's technically in its star's habitable zone."


 * Kortoso (talk) 16:33, 25 October 2016 (UTC)


 * I went ahead and added a short "disclaimer" (further improvements welcome of course). GermanJoe (talk) 02:47, 28 October 2016 (UTC)

Retouched Image
Just to say the artist's impression from the ESO website has been retouched for this article with the star recoloured from an orange white to white. I think this counts as WP:OR and I think it would be better to use the original. Robert Walker (talk) 15:44, 9 February 2017 (UTC)

Radius vs. expectation value
The source for the radius measurement gives an expectation value (i.e. a statistical mean of the possible values), not a measurement. Citing it as Radius: 1.07+0.38-0.31 implies a direct measurement or calculation with some measurement uncertainty, which I think is misleading in this case. I'm reverting to 0.8 - 1.5 since that gives the 95% confidence interval for the possible values (admittedly, this isn't made entirely clear either, so any better ideas are welcome). Dab8fz (talk) 17:46, 24 February 2017 (UTC)

A&A Paper on Proxima b
Here is a recently published paper on Proxima b: The results may be of interest to our readers. Praemonitus (talk) 20:47, 22 May 2017 (UTC)

Probability of life and environment
In fact the probability of life and the environment suggested in this article is quite in error and does not represent the most likely scenario. The mass of the planet suggest it would have a very dense atmosphere which first of all would raise the temperature to at least the temperature of the earth if not warmer. It is suggested that the solar wind would blow the atmosphere away, but that would only happen on a geologically quiet planet. A rocky planet of the mass and size of Poxima b would without doubt have at least the activity of the earth. If the atmosphere would like then be filled with more CO2 than the earth and thus would not be blown away at any rate that would compare to the model suggested here. Venus has a much higher solar wind than the earth, and it has a very dense atmosphere. Even at the very cold temperature suggested there would be a lot of liquid water on the planet. suggesting thick clouds, which would not allow much UV to reach the surface. I would suggest from my own calculations that the planet has an average temperature of 95F (35C) making it much warmer than the earth. It would have no ice t the poles and a maximum temp of 75C and a lowest of -10C. In other words very capable of life, if a little hot. The air pressure would be about 3 times that of the earth and so would shelter life from any solar flares. It is also likely that any life would have thick shells to protect them from UV. The gravity would be higher than the earth, but difficult to calculate with an unknown density. Suffice to say that the increase in gravity would also protect the planet from losses of atmosphere due to solar wind. In other words what we would expect with an average probability, instead of worse case scenario presented here is, the planet would be a hot steamy planet with large oceans and very hot tropics. Temperate poles with much less direct sunlight reaching the surface. A tropical jungle type of world is the most likely scenario with a diverse panorama of life evolving on the surface. It is a shame that such a negative scenario is presented here. I think it was done to discourage people from wanting to go there as it would not really take very long to make a craft to get there if we put our minds to it. The American Government has as official policy the dictate to suppress the idea of life existing anywhere other than earth as it may disrupt society. — Preceding unsigned comment added by 74.14.26.95 (talk) 21:30, 15 April 2018 (UTC)
 * 74.14.26.95 writes: ...from my own calculations... . Please read WP:OR. If you can find somewhere that has published this in a peer-reviewed journal, we can consider including it. Tarl N. ( discuss ) 21:49, 15 April 2018 (UTC)

Source to add
https://iopscience.iop.org/article/10.3847/2041-8213/aca487/meta and https://www.nature.com/articles/s41467-022-35187-4 Jo-Jo Eumerus (talk) 09:31, 16 December 2022 (UTC)