Talk:Proxima Centauri/Archive 2

Image of orbit
I have removed the image of the orbit around Alpha Centauri because it gives the impression that from Earth it will appear like that. The truth is that in tens of thousands or hundreds of thousands of years, the system will move way off to the west. At different times during the orbit it will be at different places in the sky, eventually ending up north of the Milky Way between Lynx and Auriga. The view from Earth will also be from a different angle compare to now, so the orbit ellipse will change. The fact is that as Proxima and Alpha Centauri move, they trace wavy curves going west, rather than making ellipses in the sky. Eventually after a long time they will be so far away that the proper motion will be small and then their paths will start to look like loops or cycloids and then eventually like spirals, getting smaller and smaller as the system recedes. I tried to explain this with a brief note in the caption, but it was removed with the comment that I have to give references. Well, the alternative is just to remove this erroneous image, which I have now done. Please don't restore it unless you explain here why I'm wrong in what I have said. Eric Kvaalen (talk) 17:32, 10 January 2018 (UTC)
 * The shape of the orbit will indeed look like that. I'm putting the image back. The background is irrelevant, it isn't marking any landmarks. Tarl N. ( discuss ) 22:21, 10 January 2018 (UTC)



I am putting the image with my caption here for reference. If you were to place an ellipse in space, moving along with the centre of gravity of the Alpha Centauri-Proxima system, then at this moment in time the ellipse would look like the one in the image. But of course the ellipse is moving with respect to us here in the solar system. By the time Proxima moves to the point marked 40 (40,000 years into the future), the ellipse will already have moved past the solar system. My guess, without doing a calculation, is that it will be somewhere near where Cancer, Hydra, and Canis Minor meet. "We", or any Earthlings around at that time, will see the ellipse from a completely different angle, so it won't look like the one in the image anymore.

If you were to draw the path of Proxima around the centre of mass of the system, as viewed from Earth, it would not look like an ellipse at all. It would look something like a spiral, first getting larger (in the distant past), and then getting smaller (in the distant future). At present it looks like Proxima is going counterclockwise around Alpha, but either in the distant past or in the distant future (I don't know which without doing a calculation) it would look like it was going clockwise around Alpha! The switch occurs when the plane of the orbit passses through the solar system. At that point in time, the orbit will or did look like a straight line segment!

For a system like α Centauri A and B, it is legitimate to make an image like this one (used in the Alpha Centauri article), because the period is only 80 years, so they go around one another many times while we watch from an almost constant angle or viewpoint. But in the case of Proxima going around Alpha, this is not the case. The period is half a million years, but it only takes about a hundred thousand for the system to pass by us.

Look, I don't mind having the image be in the article, but if so it should have a caption like what I wrote.

Eric Kvaalen (talk) 07:45, 11 January 2018 (UTC)
 * I don't have a problem with the current caption because such plots are typically presented from the system's reference frame, rather than ours. However, the image background seems unnecessary and just serves as a distraction. It might be better to convert the image to a simpler SVG format. Praemonitus (talk) 16:06, 11 January 2018 (UTC)


 * Very much agreed with Praemonitus. The image presents great information, but the background is simply distracting. I wish I had any skills making SVGs, otherwise I'd make it myself. — Huntster (t @ c) 16:56, 11 January 2018 (UTC)
 * The background image serves to give a sense of scale of the orbit. When you have a photograph of &alpha; Centauri A and B, there are no background stars visible in the image - because at that magnification and brightness, nothing else appears. In this case, there are gobs of background stars in the image because the angular separation is so wide and the brightness so low for Proxima - which serves to provide a sense of scale. If there were any meaningful landmarks in the background image (beyond &alpha; AB and Proxima), there'd be a point in claiming confusion. But as is, I don't think the image confuses anyone. If that were a problem, no images of astronomical trajectories could ever contain any other stars, because everything moves all the time in different directions, and the background won't be precisely the same as the object moves. You couldn't even show a planet's motion against a stellar background, because those stars would have shifted by some tiny amount. I don't think this image is unreasonable. Tarl N. ( discuss ) 18:43, 11 January 2018 (UTC)
 * No, there's no sense of scale because you don't know how far away the viewing position lies. For me, all the background provides is a distracting clutter that delivers no additional information. As in art, less is more. If you need a sense of scale, then I'd suggest just using an actual scale − the number of light months, for example. Praemonitus (talk) 20:43, 11 January 2018 (UTC)
 * O.k. - I'll concede. As a stargazer, I feel it gives a significant feel for the scale (as in scale relative to the sky, not in physical meters), but if you're determined, find an image that gives just the ellipse. Tarl N. ( discuss ) 23:08, 11 January 2018 (UTC)
 * Tarl, we're not in a rush. Let's give it time to see what other opinions are out there. — Huntster (t @ c) 23:51, 11 January 2018 (UTC)
 * But would you feel the same sense of scale if the names were changed to Sun and Pluto? Praemonitus (talk) 18:58, 12 January 2018 (UTC)

But you're all ignoring what I said. It's not just that the background will change with time. It's that our viewing angle changes, and much more rapidly than Proxima goes around Alpha. Don't you agree? Eric Kvaalen (talk) 05:53, 12 January 2018 (UTC)
 * I did respond to that. Apparently you ignored it. Praemonitus (talk) 15:41, 12 January 2018 (UTC)

Sorry, but I don't know what you mean. Do you mean your sentence "I don't have a problem with the current caption because such plots are typically presented from the system's reference frame, rather than ours"? I don't understand that sentence.

At present, the Alpha Centauri/Proxima system is moving toward us with a velocity of 22.4 km/s and "sideways" (proper motion times distance) at 23.4 km/s, so the angle between its velocity vector and our present line of sight is arctan(23.4/22.4) or 46°. That means that in the next 28,000 years, as it comes to its closest point to us, the angle we see it at will change by 44°. The tangent changes by 22.4/23.4 every 28,000 years, so in the previous 275,000 years (half an orbit period) the angle changes by arctan((22.4/23.4)*(275/28)) or 84°, and in the next half a period it will change by another 84°. So while the system does just one orbit, the angle at which we see it changes by 168°!

Do you agree with that?

Eric Kvaalen (talk) 06:37, 13 January 2018 (UTC)
 * Yes, I agree that the position of the system is moving from our perspective. That would be a frame of reference centered on the Earth. For an orbital plot though, that is irrelevant. The image is being presented as though we are viewing it from a location that is co-moving with the Alpha Centauri system. Does that make sense? Praemonitus (talk) 23:34, 13 January 2018 (UTC)

Well if that's true then it should be explained in the caption. Actually though, this image, and others like it, are presented as viewed from Earth. It gives the false impression that in 40,000 years, Proxima will appear at the point marked "40", and in 80,000 years at the point marked "80" and so on, at least with respect to Alpha if not with respect to the background stars. Eric Kvaalen (talk) 06:40, 14 January 2018 (UTC)
 * Orbital plots are pretty much always presented from the primary component's frame of reference. Otherwise all we'd see is a wiggly line of the proper motion that would be more difficult to interpret. Praemonitus (talk) 16:12, 14 January 2018 (UTC)

But the phrase "from the primary component's frame of reference" does not specify the view. In fact, it's not even clear what it means when you use it. It should mean a system of coordinates centred on the "primary component" (does that mean Alpha Centauri?). But to describe a view we need to specify a point from which we look at something, as well as the direction in which we look, which way is "up", what the scale is, and how all these things change with time if it's a "movie". Normally these orbit diagrams use the earth (or the solar system, let's say) as the viewpoint, and, as you say, we remove the proper motion, which is like turning our camera so that it's always pointing straight at the system. (The above image of the Alpha Centauri A & B system shows both this and also a view from a different point of view, showing the ellipse flat on.) Now, if we apply that to the Alpha/Proxima system, it means that we turn our "camera" by 168° while the system goes through one orbit. That means that the orbit gets rotated around some axis (not perpendicular to the orbital plane nor in the orbital plane) by 168° relative to the (rotating) line between us and the system. So even if we keep the system at the centre of our camera's view, the paths of Proxima and Alpha do not describe ellipses. (During the previous orbit, when the system was somewhere around Corona Austrina, it would not have moved nearly so much, but it would have drawn closer to us, so the orbit would have looked like it was getting bigger at the same time as rotating a few degrees. Overall, the system goes 180° around us, from Sagittarius to Centaurus where it is now and then on to Lynx or Auriga.)

The Alpha Centauri/Proxima system is unique in that it is the only one which is moving by us faster than the period of rotation. There are certainly other systems with periods of half a million years (though I don't think we actually know of any), but they would be far away and so would not move far through the sky during one period. There are also binary systems that are nearby (like Alpha itself, with A and B) and have a large proper motion, but they also have a relatively short period (80 years for Alpha). So in neither of these kinds of cases do we have the phenomenon that I am describing as the case for the Alpha/Proxima system -- slow period and high proper motion.

Do you agree with all this?

Eric Kvaalen (talk) 07:54, 15 January 2018 (UTC)
 * It comes down to common sense. You view the orbital plot from a position perpendicular to the plane, or else you end up distorting the elliptical shape. If you don't do it from that position, then it is necessary to present some symbols indicating the perspective. I don't see a need to clutter up the caption such obvious details, although I wouldn't be adverse to adding a footnote if the consensus is this is necessary. Praemonitus (talk) 15:49, 15 January 2018 (UTC)

Sorry, I don't understand what you're saying. You want us to show a plot from a position perpendicular to the plane? That's not what we have! By the way, viewing an ellipse from some arbitrary angle still gives an ellipse. That's not my point. My point is that we are trying to show the orbit from the perspective of the earth, but it gives the erroneous impression that in the future we (or whoever) will see Proxima in the positions marked, when in fact, the whole system will move by us before Proxima does even one orbit, and "we" will be looking at it from the other side! The image is totally misleading, and I don't see why we can't put in a longer caption to explain that this is not what one would see from the earth in the future. Eric Kvaalen (talk) 10:29, 16 January 2018 (UTC)
 * No it's not. See the original image caption here. There's nothing that says it's seen from the perspective of the Earth. It's time to move past that. Praemonitus (talk) 00:52, 17 January 2018 (UTC)

I'm pinging the others for this. The image certainly is from the perspective of the earth. (The fact that the caption talks about the background stars is an additional confirmation. Also notice that Alpha is not near the focus of the ellipse, so it's certainly not looking at it from perpendicular to the orbital plane.) Take a look at Figure 1 in the article by Kervella et al, which is the source. They explicitly say that it's the view on the sky. Tarl and Huntster, what do you say? Eric Kvaalen (talk) 08:06, 17 January 2018 (UTC)
 * Well, if that were true, I'd say it's an overlay projection of the orbital plot on the background, rather than an expected future view. Praemonitus (talk) 17:31, 17 January 2018 (UTC)
 * Yeah, as best I can tell, it's a projection of the orbit as seen from earth. That's why I think the image as it stands is useful, it provides a sense of scale for the angular size of the orbit compared to the background - unusual for a multiple star, there are many other stars in the field of view. Note that "orbit" means the closed curve which the object moves on, which is distinct from actual trajectory traveled by the object (which could be a helix when you account for proper motion). We can project the entire closed curve of an orbit without requiring an object travel along it, which is what that image is doing. The year markers along the curve give an idea of just how slowly Proxima travels along that orbit. Tarl N. ( discuss ) 17:55, 17 January 2018 (UTC)

Fine, but then let's explain in the caption that Earthlings will not see Proxima in the positions marked. Do we all agree on that fact now? Eric Kvaalen (talk) 09:20, 18 January 2018 (UTC)
 * You're making a mountain out of a molehill. That's like saying an image of a ship at sea needs to be caveated that the particular waves you see won't be there the next time you look at the ship. Tarl N. ( discuss ) 17:28, 18 January 2018 (UTC)
 * Nope. It would just add clutter with no particular benefit. Praemonitus (talk) 19:28, 18 January 2018 (UTC)

I think it's an interesting fact, and I think that the present image is very misleading. It's not at all like talking about a ship going through different waves. (Remember, I'm not talking about the background.) You do realize that this system is different from all the others? In other cases, if you were to point a telescope at the system and put it on a mount that keeps it pointed at the system for tens of thousands of years, taking a movie, then if you watch the movie in fast motion, you would see both stars moving in near perfect ellipses. But in this case, it's not at all like that, at least not now. It was like that millions of years ago, and will be again millions of years hence. But now, from say half million years ago till half a million years from now, Proxima is not making ellipses around some moving point in the sky. Do you agree with that? Yet that is what the image implies. Eric Kvaalen (talk) 20:19, 19 January 2018 (UTC)
 * 3000 words later, you haven't convinced me the image is misleading. I think it shows an orbit (an instantaneous closed curve, as opposed to a prediction of location) projected from the viewpoint of earth, against the current background of stars. I think the image is useful in showing the scale of the orbit as seen from earth. It does not show the future trajectory of either star, and would be misleading only if it identified particular landmarks and implied future location relative to such landmarks. Since you don't seem to be getting consensus, if you insist on changing this, you'll have to proceed through other means - WP:3O, WP:DRN, WP:M, ...
 * I do suggest that you re-read WP:WALLOFTEXT and keep that in mind. I've ignored several of your discussions on this and other pages because I simply didn't have the time to spend going through pages after pages of your arguments. Regards, Tarl N. ( discuss ) 02:05, 20 January 2018 (UTC)

It's all because of four lines of caption that I wanted to add to an image to clarify things. I still don't know whether you two have understood what I'm trying to say, because when I ask whether you agree with what I claim, you don't answer. Eric Kvaalen (talk) 08:09, 20 January 2018 (UTC)


 * I think the point deserves a little explanation, maybe not four lines. It would be nice if we had a diagram/plot of the projected proper motions of A/B & C for comparison, putting the orbit in scale with the space motion. However, what about captioning the present one something like Orbital plot of Proxima Centauri superimposed to scale on a recent photograph&thinsp;? (Addition in bold.) That would alert readers to the distinction between the present-day appearance and the plot’s extension through time, without going into too much detail.—Odysseus 1 4 7 ' 9 ' 08:34, 20 January 2018 (UTC)


 * In private communication with one of the authors of the Kervella paper, he suggests that we say in the caption that the image represents the trajectory of Proxima relative to the barycentre of the system, projected on the plane perpendicular to the Sun-Alpha Centauri vector (the present "plane of the sky"), and that the marked time-points simply give an indication of the position of Proxima relative to AB in this plane. Eric Kvaalen (talk) 11:09, 20 January 2018 (UTC)
 * I don't go around handing out barnstars and such, nor have I paid attention to every twist and turn of this saga, but I feel compelled to commend you for your efforts on this, Eric. You were absolutely right to pursue this issue and you've gone beyond the call of duty in your efforts to find the proper wording for the caption. I have to say, I'm impressed. nagualdesign</b></b> 16:31, 20 January 2018 (UTC)
 * Given the mass distribution of this system, the barycentre is probably indistinguishable from the blur that is Alf Cen AB. So yes, it's a projection of the orbital plot as seen from the perspective of the Earth. I was mistaken in my initial assessment of thinking it was from a position perpendicular to the orbital plane. But to me that's a communication failure with the original ESO caption. That being said, I still see no reason to change the current caption. Possibly the wording on the image page needs revising. Praemonitus (talk) 15:58, 20 January 2018 (UTC)

So I'd like to know, do we agree on the facts? Do we all agree now that the image is from the point of view of the earth, that the system moves through a large angle in the sky as it executes the present half-million-year-long orbit, and that during the present orbit "we" see the elliptical orbit from many different angles and many different distances as the system passes us by? Eric Kvaalen (talk) 13:14, 22 January 2018 (UTC)


 * I honestly don't know how to react to all this. On one hand, as someone interested in this subject material I find the discussion interesting. But looking at it from a lay person's perspective, I'm honestly facepalming. I feel that's the key, here: the vast majority of our readership are laypersons who couldn't care one whit that the image won't be accurate in 28,000 years, or 40, or 80. They will find the image interesting because it represents what the system looks like from our perspective right now, and that perspective will not change in any meaningful way during our lifetimes. For educational purposes, it is absolutely appropriate to make sure that the change in perspective is explained in the prose, but the ratio of effort expended here thus far versus the value to the end user is unreasonable. Remember, WP:KISS, especially in the relatively limited space of an image caption. — Huntster (t @ c) 14:28, 22 January 2018 (UTC)
 * Amen. <b style="color:green">Tarl N.</b> ( discuss ) 16:19, 22 January 2018 (UTC)


 * The current caption remains correct, does it not? It is brief and to the point. I think that further details can be made available on the image page or in a footnote, for the few readers who are interested. Praemonitus (talk) 18:57, 22 January 2018 (UTC)

Well, I still don't know the answer to my question of yesterday. But never mind. I agree that the ratio of effort to value was large. Originally Praemonitus objected that what I wrote was unsourced, which implies that he probably thought it was untrue. So I tried to convince him. Now he says the caption as it stands is correct -- true, but we should put things in that are interesting. I will make a footnote. Eric Kvaalen (talk) 14:35, 23 January 2018 (UTC)
 * Yes, my two remarks aren't contradictory. The original caption on the article still appears correct, and your preferred wording was unsourced. I didn't necessarily disagree with your position. It just seems a bit of a bunny trail that distracts from the core topic. Praemonitus (talk) 15:27, 23 January 2018 (UTC)
 * For what it's worth, I'd like to respond to the comment: Praemonitus objected that what I wrote was unsourced, which implies that he probably thought it was untrue.
 * NO.
 * Whether he thought it was untrue or not, unsourced comments are not allowed. Period. The whole point of Wikipedia is that we report what others have written (see WP:SECONDARY), and document where it has been reported. The idea is that a librarian should be able to maintain the articles, without needing to be an expert in all the subjects wikipedia covers. Writing the articles requires expertise. Precluding vandalism should not. And edits which don't document their source should be kept out. Even if accurate. <b style="color:green">Tarl N.</b> ( discuss ) 22:42, 23 January 2018 (UTC)

Regarding the added footnote, please note that this is a featured article which means it is held to the highest standards for Wikipedia. That includes no original research or unnecessary vagueness. Vague relative words like 'far' should be clarified. How far? 100 km is far for me. However, numbers require citations for confirmation. If it can not be specifically referenced, then it should either be a quote from a notable individual or kept out. Participating in the WP:FAC process is a good way to get familiar with these types of requirements and to understand why they are subject to scrutiny. Praemonitus (talk) 19:22, 24 January 2018 (UTC)

You just reverted my edits. First you took the word "far" out of the sentence "In thousands of years, when Proxima has progressed further in its orbit, the system will have moved far to the west and Earthlings would see it from a different angle and with a different background", saying it was "vague". Then when I put in a more specific figure "about 70°", you reverted, complaining that I have no reference!

I think you're not acting in good faith. You do not own this article.

If you take out the word "far", then you remove the whole point. We have discussed this for the last couple weeks. Do you really not believe that it will move far to the west? Do I need to explain to you again why it's about 70°? Or do you understand, but you want to make sure I don't succeed in conveying this point to the readers? All this just about one little word! But an important word.

Eric Kvaalen (talk) 20:19, 24 January 2018 (UTC)


 * Then let me be clear: do not use relative terms, and do not add unsourced information, especially when it has been specifically challenged. — Huntster (t @ c) 20:39, 24 January 2018 (UTC)


 * I'm just going to ignore your insults here and try to deal with the facts. To be frank, your unsourced talk-page calculations just don't matter because they are considered WP:OR. What if somebody later comes along and changes it, saying the value is wrong? What do we do? That's why we need sources to make this encyclopedia accurate. Likewise, saying vague words like "far" can prove confusing to the lay reader because it is a relative term with no definite meaning. If we're going to get through this, then I'd like to see definitive wording with sourced data. That will help us anchor the information and keep it intact for future use. If citations aren't available, then tough.


 * To cite something like this, I recommend looking for a reliable source that demonstrates exactly what you are trying to present. You can then use WP:CALC and present your calculation, step by step. That will allow others to check your work at a future date. Thank you. Praemonitus (talk) 21:36, 24 January 2018 (UTC)

I did not insult you.

You did not answer my questions. Do you agree that it moves about 70° or not? To quote WP:CALC which you refer to, "Routine calculations do not count as original research, provided there is consensus among editors that the result of the calculation is obvious, correct, and a meaningful reflection of the sources." It's a routine calculation, which I think you are capable of understanding. I will repeat it here:

The system is moving towards us at about 45° (velocity component towards us is 22 km/s, and sideways component is 23 km/s). So in 28,000 years, when it gets to the point nearest the solar system, it will have moved by 45°. At any point in time, one can draw a right triangle going from the sun to the point of nearest approach, from there to the Alpha/Proxima system, and from there back to the sun. (The right angle is at the point of nearest approach.) The line from here to the point of nearest approach is like the cosine (times the hypotenuse), whereas the segment from there to the system is like the sine (times the hypotenuse). The latter changes linearly with time. So the tangent changes linearly with time. In 28,000 years it changes by about 1 (from 1 to 0). So in the next 12,000 years after closent approach it will change by 12,000/28,000, which means the angle will change by arctan(12/28) or 23°. So in all, over the next 40,000 years, the angle will change by 45°+23°=68°. Approximately. The point is, it's a lot! To just say the system will have "moved west" misses the whole point. That could mean it moves west by 1°.

Eric Kvaalen (talk) 06:56, 25 January 2018 (UTC)
 * The calculations you are presenting are original research. They are not "obvious, correct, and a meaningful reflection of the sources". Among other things, I don't see a source for your velocity vectors as stated. I assume you calculated the lateral motion, rather than finding it in a source. Regardless, the calculations could be done, but they would still not be obvious unless you provide them in better detail than above. You'd have to provide the vector calculations to produce an actual answer, not a handwaving approximation in words.
 * Even if you did that, you probably wouldn't get consensus on making your change. To re-use the ship analogy, it's like presenting a picture of a ship with a rotating radar dish sketched in, and wanting to add to the caption saying "by the time the dish finishes a rotation, this picture will be inaccurate because the ship will be foreshortened." That's meaningless trivia. <b style="color:green">Tarl N.</b> ( discuss ) 09:01, 25 January 2018 (UTC)
 * In addition, I'll comment that you seem to find a need to publish your thoughts. Wikipedia is not the place for that. If you want to publish your thoughts, write articles for publications, elsewhere. <b style="color:green">Tarl N.</b> ( discuss ) 09:03, 25 January 2018 (UTC)


 * "Do you agree that it moves about 70° or not?" My opinion on that doesn't matter because it's OR. Praemonitus (talk) 19:19, 25 January 2018 (UTC)

It's not that the ship will be foreshortened. It's that the ship passes us by, moving by 168°, while the radar dish does one single rotation!

My source for the veloctiy components is the article by Kervella referenced in the Alpha Centauri article, namely this. I calculated the sideways component by the Pythagorean theorem.

I accept that saying that the system will move 70° over the next 40,000 years borders on original research (although it is trivial, and we could easily ask the researchers whether it is correct). But all I wanted to do was to put in the word "far". I thought you would be able to follow the argument for why it will move far. (I think whether you agree is important, Praemonitus, because if you believe that it moves 70° and yet you refuse to let me add the word "far", then I question your motives.) Do you accept that in 28,000 years, by the time it gets to its point of closest approach, it will have moved by 45°? Surely you can understand that. It doesn't involve any arctangent.

Eric Kvaalen (talk) 06:14, 26 January 2018 (UTC)
 * Look, I understand and follow your arguments. However, you are in error by asserting that the vague word "far" describes an angular movement. Until you provide a properly cited statement for your values, there's nothing further to discuss. I am also starting to question your motives in this matter. Praemonitus (talk) 15:58, 26 January 2018 (UTC)
 * The above comment by Praemonitus was changed on the 27th at 17:20. When I responded it just said "Look, I understand and follow your arguments. But until you provide a properly cited statement, there's nothing further to discuss." Eric Kvaalen (talk) 16:15, 29 January 2018 (UTC)

, you seem to agree that if we have consensus that the star system moves far in 40,000 years, then we can put the word "far" back in. Praemonitus acknowledges that he follows my argument. What about you? Do you agree that it moves far in 40,000 years? Eric Kvaalen (talk) 16:45, 27 January 2018 (UTC)
 * It's vague, irrelevant to the picture, and, uncited. That it moves a considerable distance in 40,000 years isn't in dispute - it has a proper motion, thus it moves. The disagreement you're having with Praemonitus is how to characterize that, plus that you have no citation for your conclusion. The disagreement with me is that it's irrelevant at the point where you want to put it, and that your WP:OR calculations are neither obvious nor trivial - as demonstrated by the fact that you haven't actually carried them out (you've hand-waved approximations). From a maintainability viewpoint, adding such calculations is purely WP:OR. The current note is clumsy, if I made any changes I'd probably re-word it to something like "Note that by the time Proxima completes one orbit, the entire Alpha Centauri system will have moved to another part of the sky, so the perspective and background will be different". Even that, I'd regard largely obvious trivia. <b style="color:green">Tarl N.</b> ( discuss ) 17:56, 27 January 2018 (UTC)


 * FWIW Meeus reports that α Cen will pass within less than a degree of β Cen, their closest approach occurring c. 5940. That represents over 4° of proper motion in 4000 years. He doesn’t extrapolate any further than that, though.—Odysseus 1 4 7  9  19:38, 27 January 2018 (UTC)
 * Thanks. That would certainly verify Tarl's proposed caption. Praemonitus (talk) 20:56, 27 January 2018 (UTC)

, the question is not whether it moves "a considerable distance". The question is whether it moves by a large angle. Look, if you don't follow my "hand waving" explanation (not even the fact that it will move 45° in the next 28,000 years?), then just do a simple calculation of how many light-years it will go in the next 40,000 years! It's trivial. It comes to about 4 light-years, and it's moving presently at about 45° away from "vertical". It's presently 4 light-years away. So obviously it will move through a large angle, not just during the present orbit, but just in the next fraction of an orbit (40,000 years out of half a million). But I accept your proposed version of the note (with a slight change), so I will make it. Eric Kvaalen (talk) 16:15, 29 January 2018 (UTC)
 * It's not that I don't follow your explanation, it's that you hand-wave the hard calculations and get them wrong. You have to do a 3-dimensional vector translation (convert from r/RA/DEC to xyz in km, apply linear translation with xyz velocity in km/s, convert from resulting xyz in km to r/RA/DEC, and calculate angular separation). It's a couple of hours of work to set up for me, which I haven't had time to do. It's non-trivial, as demonstrated by the 6000 words of argument over 19 days, and nobody has done it. It's blatantly WP:OR, particularly since I have not seen a published value for Alpha Centauri's transverse velocity and direction. It's derivable, but each step is one further beyond the "obvious and trivial". The hand-waving calculations are fine for order of magnitude (for example, good enough for removing a claim that it would move 4˚ in the next century), but not sufficient for adding a specific comment on how far it will move in a half-million years. See WP:CITOGEN for examples of why it pays to be anal-retentive on prohibiting WP:OR. <b style="color:green">Tarl N.</b> ( discuss ) 22:57, 29 January 2018 (UTC)


 * From Anderson and Francis (2012), for Proxima Centauri I get a total heliocentric velocity of 32.6 km/s. Ignoring the effects of galactic gravitational potential, over 40,000 years that translates to $41,151,000,000,000 km$, or 41.15/9.46 = 4.3 light years traveled. In astronomical terms, that's not much. Plus the actual value is off-topic WP:TRIVIA that adds no value to the article. Praemonitus (talk) 00:41, 30 January 2018 (UTC)
 * Well, I can no longer say I've never seen transverse velocity published. The XHIP catalog gives me u,v,w vectors in km/s, with the commentary that these should be safe for linear motion calculations up to 2MYr. But where are you getting 32.6 km/s from, however? I get 31.896 km/s for A and 30.243 km/s for B. That's from U,V,W values of A=(-29.3,0.3,12.6), B=(-26.2,-0.4,15.1). (Retrieved from VizieR specifying Alpha Centauri and clicking the u,v,w selections). Which still leaves the issue of the overall system's motion unresolved - and calculating that from scratch is even less obvious and trivial. <b style="color:green">Tarl N.</b> ( discuss ) 02:19, 30 January 2018 (UTC)
 * I went to the Vizier form and selected the UVW field for HIP 70890. But you're right, I should be using Alf Cen AB since Proxima Cen probably includes an orbital velocity component. Praemonitus (talk) 02:54, 30 January 2018 (UTC)


 * O.k. - I did a rough calculation. See pdf for my rough calculations, using only Alpha's proper motion. This is very rough, since my source numbers are so rough. But I ended up calculating that Alpha Centauri will be in the Pictor constellation near where Canopus is (now) in 40,000 years (obviously neither Canopus nor Pictor will be there at the time). Total motion about 50˚ in 40,000 years. <b style="color:green">Tarl N.</b> ( discuss ) 03:49, 30 January 2018 (UTC)
 * And this is why you don't use WP:OR on Wikipedia. I got a sign wrong. It will be in Hydra, not Pictor. Galactic longitude 257, Galactic Latitude +29˚. <b style="color:green">Tarl N.</b> ( discuss ) 03:49, 30 January 2018 (UTC)

, it wasn't necessary to do a detailed calculation as you describe. The question was how far (in angle) the system will move in the next 40,000 years. For that all you need is its velocity components toward us and sideways (which you can easily get using the Pythagorean theorem), and its distance now. By the way, since we know that it presently moves about 1° per thousand years, and that the figure will be greater than this over the next 56,000 years because it will be closer to the sun, then obviously it will move more than 40° in the next 40,000 years. And it is moving generally west, along the line of the Milky Way. I did calculate the velocity components of the Alpha/Proxima system. Proxima changes the result very little since it has approximately the same motion relative to us as Alpha and because its mass is much smaller.

But I don't need to convince you of all this since you have finally allowed me to add my note, although Praemonitus shoved it into a footnote where no one will see it.

Eric Kvaalen (talk) 14:32, 30 January 2018 (UTC)
 * Yeah, I shoved it back in a note where it was before, and as agreed during the discussion above. It's not like there aren't other explanatory comments in the notes section, so spare us your trivial indignities and just use a mouse-over to read it. WP:EGO. Praemonitus (talk) 18:12, 30 January 2018 (UTC)

Dust rings
Dust rings reported in November may not exist But when MacGregor, Weinberger, and their team looked at the ALMA data as a function of observing time, instead of averaging it all together, they were able to see the transient explosion of radiation emitted from Proxima Centauri for what it truly was. "There is now no reason to think that there is a substantial amount of dust around Proxima Cen," Weinberger said. "Nor is there any information yet that indicates the star has a rich planetary system like ours."
 * Preprint, Accepted to ApJL. Lithopsian (talk) 19:45, 27 February 2018 (UTC)
 * Thank you. I've updated the article and removed the entries from the planetary system table. Praemonitus (talk) 21:28, 1 March 2018 (UTC)

The giant planet of ~0.31 Jupiter mass should probably be removed from the planetary system table as well. There is clearly no evidence of this planet's existence. -- J P


 * Given the variable nature of this star, it's probably a good idea to only list confirmed candidates. Praemonitus (talk) 21:36, 13 March 2018 (UTC)

Major image is messed up
HST imagery would not show these streaks of light at 90 degree angles. This imagery has been artifically processed, so its accuracy is questionable. This is NASA promotional imagery, not truly scientific. Also, References to this picture refer to WW2 which has nothing to do with the image either. --2600:6C48:7006:200:D84D:5A80:173:901D (talk) 04:44, 15 March 2018 (UTC)
 * I can't tell if you're trolling or serious. There could be any number of reasons for the 90 degree angle; most likely it is simply aesthetics because it looks a bit nicer with the rays going toward the corners rather than the edges. Doesn't change the quality or accuracy of the image, and certainly doesn't make it any less scientific. Also, I have no idea what "References to this picture refer to WW2" means, so we're going to conveniently ignore that nonsense. — Huntster (t @ c) 06:27, 15 March 2018 (UTC)
 * JFTR those “streaks” are just diffraction spikes, nothing to do with digital manipulation.—Odysseus 1 4 7  9  08:13, 15 March 2018 (UTC)
 * Yes, that. Forgot to say that. Thanks Odysseus. — Huntster (t @ c) 12:07, 15 March 2018 (UTC)
 * Seriously? OK, I'll assume good faith.  What the others said, obviously.  Have some fun and look up your favourite objects at the Hubble legacy archive.  You will probably be astonished at just how crude raw HST imagery is, if all you're used to is the highly-processed and "artificial" images shown on most space porn websites.  They're not colour for a start (deliberately), although the same frames may be available at several wavelengths that can be combined to form a (real- or false-) colour image.  They are "noisy", that is covered in spurious specks or streaks in addition to the optically real aberrations such as diffraction spikes.  They also tend to show very little detail because of the unbelievable range of brightnesses contained within the raw image, which must be adjusted to a range that is visible to viewers while covering the detail that is considered important in that image (and possibly not showing other important details).  Lastly, which surprises many people, is that the image frames tend to be a weird shape and orientation rather than a simple north-is-up (or down if you're old school or living in the less-populated hemisphere) square that you might expect.  Occasionally this is visible in a final processed image, but often it is obscured by tilting the image so that north is off at some angle, or cropping it so that north can be up on a nice square palette.  Lithopsian (talk) 15:01, 15 March 2018 (UTC)


 * The Hubble FAQ has an explanation for the spikes. It's well understood scientifically. Praemonitus (talk) 15:51, 15 March 2018 (UTC)

Density calculation
The density is calculated in the "explanatory notes" using 0.145*R_sun, but the stellar radius is listed in the info box as 0.154*R_sun. Since volume is proportional to the cube of radius this results in a significant discrepancy.

Mean density is currently listed in the "characteristics" section as 56.8 g/cm^3 using 0.145*R_sun, but in fact works out closer to 47.0 g/cm^3 using 0.154*R_sun. Lord Parkin (talk) 05:23, 14 March 2018 (UTC)


 * It's a meaningless value anyway since it's only relevant at one (undefined) interior layer of the star. It might be more useful to discuss surface gravity instead. Praemonitus (talk) 14:27, 14 March 2018 (UTC)


 * The overall density of a star is a moderately pointless thing to calculate. Possibly the point being made in this article, that it is 40 times denser than the sun, is interesting although I don't know if it has to be in the lead.  Looks like a typo in the calculation though.  Lithopsian (talk) 17:32, 14 March 2018 (UTC)


 * I've updated the calculation using the values in the infobox. Praemonitus (talk) 20:22, 16 March 2018 (UTC)

Whole star convection?
In the "Characteristics" section of the article, it is said: "Because of its low mass, the interior of the star is completely convective, causing energy to be transferred to the exterior by the physical movement of plasma rather than through radiative processes." The only source cited for this is [22], but, as far as I can see, it I does't say that the star is "completely convective". It does discuss what amounts to persistent convection over a long time, but, again, as far as I can see, not whole body convection. Attic Salt (talk) 12:58, 20 September 2018 (UTC)
 * Unfortunately it's implicit: "First, notice that the star remains convective for 5.74 trillion years. As a result, the star has access to almost all of its nuclear fuel for almost all of its lifetime." I'll see if I can dig up a second citation. Praemonitus (talk) 15:59, 20 September 2018 (UTC)

Diameter can be measured directly ????
Article's introduction 2nd paragraph says: "Because of Proxima Centauri's proximity to Earth, its angular diameter can be measured directly." I can find no evidence or cite for this, and it seems it is just calculated from stellar parameters. e.g. inferred. Due to its faintness, stellar interferometry will not work, which is the only direct method available today.

Statement should be removed unless it can be referenced as such. Arianewiki1 (talk) 02:27, 23 September 2018 (UTC)
 * Ségransan et al. (2003). Citation #12 in the article. Praemonitus (talk) 03:06, 23 September 2018 (UTC)

Proxima c
Something to watch for once it gets published somewhere more substantial than twitter:

https://twitter.com/LeeBillings/status/1116788239396851712

©Geni (talk) 22:54, 12 April 2019 (UTC)


 * And also of course, the Breakthrough Discuss: Day 2, Session 2 video on facebook (and other sites too): here — Preceding unsigned comment added by 86.162.210.247 (talk) 22:43, 13 April 2019 (UTC)


 * First of all, since err... Erm.. Our results are still under revision, and so embargoed. We, erm.. please don't, we ask you don't, not to advertise these results outside. Err... So, thank you for the comprehension. — Preceding unsigned comment added by 86.158.124.111 (talk) 07:10, 22 April 2019 (UTC)


 * It is appropriate to wait until the results are fully verified. False planet findings have happened before. Praemonitus (talk) 15:43, 22 April 2019 (UTC)

WISE Data
Hasn't WISE ruled out any brown dwarfs closer to us than PC?

05:20, 31 August 2019 (UTC) — Preceding unsigned comment added by CrackDragon (talk • contribs)
 * Do you have a reference? There's an informal reference here, but it's not peer-reviewed. Praemonitus (talk) 12:55, 31 August 2019 (UTC)
 * This was published in July 2012, https://phys.org/news/2012-06-wise-brown-dwarfs-home.html and https://iopscience.iop.org/article/10.1088/0004-637X/753/2/156. DrKay (talk) 16:12, 6 September 2019 (UTC)

Distance
Problems still continue. Distance 4.246ly in the infobox, should correspond to 4.25ly in the article body. And even the parallax 768.13mas in the infobox does not correspond with the citation number 2, page 12, where is 774.25mas. — Preceding unsigned comment added by 167.58.188.232 (talk) 20:52, 29 March 2016 (UTC)
 * Citation 2 shouldn't have been used for the parallax reference because the data comes from van Leeuwen (2007). These types of issues can happen with open wikis. Praemonitus (talk) 22:39, 29 March 2016 (UTC)


 * Ok, but citation 1 (van Leeuwen 2007) has no explicit reference to Proxima parallax. — Preceding unsigned comment added by 167.58.78.217 (talk) 06:00, 31 March 2016 (UTC)

One of the pictures has "distance" where it should be "discovered" in 1915 or whatever. Someone who is a serious wikipedian can put this properly. — Preceding unsigned comment added by 82.2.122.59 (talk) 12:28, 30 October 2015 (UTC) The first paragraph states that Proxima Centauri is "about 4.22 light-years distant". Yet the sidebar gives a distance of 4.243ly. There is no reference for either. A professional astronomer should identify a definitive reference and one (or both) of these numbers should be corrected. KevinTernes (talk) 13:21, 8 August 2012 (UTC)
 * At one point they did match, but somebody took it upon themselves to use an obsolete reference to insert a superseded value. I'm surprised it took this long for somebody to notice, so thanks for bringing it up. In the infobox, the parallax information is cited and that data is used to compute the distance. I've corrected the lead and article body to match, then removed the obtuse kilometre value because for most people it is unhelpful. Regards, RJH (talk) 15:32, 8 August 2012 (UTC)

More on distance. In the Observation section, we see, "In 1917, at the Royal Observatory at the Cape of Good Hope, the Dutch astronomer Joan Voûte measured the star's trigonometric parallax and confirmed that Proxima Centauri was the same distance from the Sun as Alpha Centauri." However, the wiki article gives the distance to Alpha Centauri as 4.37 ly, not 4.24 ly. One cannot "confirm" something that is false. I didn't try to fix it, because I don't know if Voûte made an error, or whether his level of accuracy was maybe one digit, i.e. 4 ly. If it is the latter case, then maybe add the word "approximately", i.e. "was approximately the same distance..."77Mike77 (talk) 17:03, 18 March 2013 (UTC)
 * It is in such a wide orbit around Alpha Centauri that the distance is noticeably different. --JorisvS (talk) 23:13, 18 March 2013 (UTC)
 * I see. Perhaps, then, the phrase "at that time" could be added for clarity. I will add that later if there is no objection.77Mike77 (talk) 00:11, 20 March 2013 (UTC)
 * The only concern I have is that the new phrasing ("It is currently 4.24 ly from the Sun" [italics mine]) might give people the impression that this distance changes on "small" time scales, i.e. within a human lifetime or so (which isn't true). The distance to Proxima is just about as constant as (or rather more constant than (!)) that to other stars (as can be seen in the graph in the article). Saying only here that the distance is "currently" something and not adding the same qualifier to the distances to other stars hence gives an incorrect impression of the situation. --JorisvS (talk) 18:42, 20 March 2013 (UTC)
 * I put in "currently" because of this other statement. "In 1917, at the Royal Observatory at the Cape of Good Hope, the Dutch astronomer Joan Voûte measured the star's trigonometric parallax and confirmed that Proxima Centauri was the same distance from the Sun as Alpha Centauri." If it was the same distance away as Alpha Centauri (4.37 ly) in 1917, and 4.24 ly away today, then I thought it was appropriate to say "currently 4.24 ly from the Sun". Perhaps the info needs to be reorganized so that these ideas aren't so separated. There is also the idea that Proxima is in a wide orbit around the Alpha binary, with distance from the Sun varying periodically, as you noted above. I'll think some more on this.77Mike77 (talk) 19:34, 20 March 2013 (UTC)

--- The distance DOES vary periodically, on a scale of 10s of thousands of years --- — Preceding unsigned comment added by 2.97.119.194 (talk) 21:27, 15 January 2020 (UTC)


 * This site http://www.saao.ac.za/~isg/proxima.html says that Voûte was wrong:
 * "Eighty-two years after the Cape discovery, Robert Innes at the Union Observatory in Johannesburg found a fainter star near alpha Cen that he suspected was a third but somewhat separated member of the same system. Its distance was measured over the following two years by Joan Voûte at the Royal Observatory and by Innes himself, unknown to each other. Innes prematurely declared it to be closer than alpha and named it 'Proxima Centauri', or 'Proxima' for short. Voûte's better-quality observations suggested it was no closer then alpha but, in fact, he was wrong and Innes was right, largely by chance!" So maybe the word "confirmed" needs to be changed. There are numerous sites that have copied the wikipedia article, and not much else.77Mike77 (talk) 20:10, 20 March 2013 (UTC)
 * I don't know about the history, you could be right about the "confirmed", but I don't really care what you do with it. What the "same distance" is supposed to mean is that the difference in the distances in so small that the stars are associated with each other (as opposed to very different distances). --JorisvS (talk) 20:42, 20 March 2013 (UTC)

Discussion of being nearest to Sol makes no sense
"Proxima Centauri has been the closest star to the Sun for about 32,000 years and will be so for about another 25,000 years, after which Alpha Centauri A and Alpha Centauri B will alternate approximately every 79.91 years as the closest star to the Sun" - it is supposed to be nearest to Sol in ca. 25-27,000 years' time, depending on which study one believes. But then it will move further away for several thousands of years (conceivably, for 57,000 years) before it stops being the closest and Alpha A & B take over. — Preceding unsigned comment added by 2.97.119.194 (talk) 21:23, 15 January 2020 (UTC)
 * Do you have sources for that? Lithopsian (talk) 21:30, 15 January 2020 (UTC)

Proxima c confirmed; system inclination determined
https://arxiv.org/abs/2003.13106 SevenSpheresCelestia (talk) 01:00, 31 March 2020 (UTC)
 * I removed "(unconfirmed)" from the entry for Proxima c in the planetary system table. User:Lithopsian then added "(candidate)", with the comment "call it candidate then, all the references do". Planets detected by radial velocity are always referred to as "candidates" whether they are confirmed or not (for example, the discovery paper for Proxima b calls it a candidate), and since Proxima c has now also been detected by astrometry there can be little doubt about its existence. I see no reason to have "(candidate)" in the planetary system table. SevenSpheresCelestia (talk) 22:16, 31 March 2020 (UTC)
 * The paper you link calls it an "exoplanet candidate" in the title and throughout the text. The paper uses the existing candidate orbital parameters and the Kervella et al. (2019) proper motion anomaly of Proxima to constrain the possible orbital parameters of such an exoplanet.  It doesn't confirm its existence or say anything about confirming its existence.  As soon as you find a paper that calls it a "confirmed exoplanet" or perhaps just "exoplanet" without qualification, then we can call it confirmed.  Lithopsian (talk) 15:02, 1 April 2020 (UTC)
 * Will this do? SevenSpheresCelestia (talk) 16:53, 2 April 2020 (UTC)
 * Possible direct imaging detection now. SevenSpheresCelestia (talk) 01:10, 15 April 2020 (UTC)

Since Proxima Centauri c has been confirmed, would it be a good idea to give it is own article or wait until there is more information on it? Adauchi (talk) 17:19, 15 July 2020 (UTC)

New paper with potential third planet
https://arxiv.org/abs/2005.12114 SevenSpheresCelestia (talk) 01:31, 26 May 2020 (UTC)
 * I think the relevant quote is We find some evidence for the presence of a second short-period signal, at 5.15 days with a semi-amplitude of only 40 cm·s" (my italics). Reading the article, there are further qualifiers, barely significant and discussing the signal, casts doubt on its planetary origin. This isn't a paper describing a discovery, it's a paper saying "we see something at the edge of our capabilities, but it's probably not a planet". <b style="color:green">Tarl N.</b> ( discuss ) 04:27, 26 May 2020 (UTC)
 * Should still be mentioned in the article. SevenSpheresCelestia (talk) 16:29, 26 May 2020 (UTC)
 * Perhaps slightly less marginal than earlier evidence found, back in 2012, for a planet closely orbiting at 5.6 days - https://arxiv.org/abs/1202.2570 (Bottom of section 4.1 "Proxima, a flaring M4V")
 * Should the article include the words "Proxima d"? I feel like using "Proxima d" in the article gives general readers the false impression that the signal is planetary in origin — however the paper only speculates that it might be a planet. I propose removing "Proxima d" from the article (maybe the infobox also but I'd like opinions on that) and replacing it with a description of the signal. The name "Proxima d" can be mentioned in a note explaining that if the signal is planetary it would be named as such. Supernova58 (talk) 20:47, 8 August 2020 (UTC)
 * I agree, the paper does not describe the signal as "Proxima d", unlike for b and c. It is clear from the paper they are far from convinced it's real and not just a spurious detection:
 * "However the planetary origin of the signal is far from guaranteed. Though the posterior distributions and the fit look good, the model is only barely significant over the 1-planet model, and no significant peaks at this period show up in the previous periodograms. Section 5 shows an inconsistent presence of the signal across the ESPRESSO wavelengths, which casts doubts on its planetary origin."
 * I took a similar approach with Lacaille 9352 where there is also a third signal of dubious veracity. We should mention the signals but be clear the authors aren't claiming them to be bona fide planets.ChiZeroOne (talk) 21:37, 8 August 2020 (UTC)
 * Thanks! I'll start working on that! I'm probably going to leave the infobox alone (for now) as it has been edited a bit recently and I want to make sure other editors agree before changing it. In your opinion though, should the infobox "d" entry stay as it is, be modified, or removed entirely? Actually I think I'm going to wait ~24 hours before making any changes related to the potential third planet so that others have time to contribute an opinion as well if they wish :) Supernova58 (talk) 23:31, 8 August 2020 (UTC); edited 23:34, 8 August 2020 (UTC)


 * I think it would be prudent to err on the side of caution and not include this detection just yet. It's not listed in the exoplanet encyclopedia. Praemonitus (talk) 21:06, 9 August 2020 (UTC)

Image issue
the proxima centauri star image is all messed up, have you used an diffrent image for example a sun false color image taken with ultraviolet light? — Preceding unsigned comment added by Unknownverse Productions (talk • contribs) 19:12, 24 September 2020 (UTC)


 * I don't see anything wrong with it. It's a star image showing diffraction spikes, which is normal for the brightest star in the field of view. What's the problem? <b style="color:green">Tarl N.</b> ( discuss ) 21:40, 24 September 2020 (UTC)
 * Not a particularly informative or attractive image though, just an over-exposed dot. Perhaps something like this would be better for the main image?  The orbital plot already in the article is another possibility.  Lithopsian (talk) 13:14, 25 September 2020 (UTC)
 * , I like your suggested image. It adds a bit of perspective on Proxima's tiny relationship to Alpha Centauri. Attic Salt (talk) 19:16, 25 September 2020 (UTC)
 * It's a nice image true, but at the normal WP size it's impossible to view the little circle. All we're really seeing then is Alpha Centauri. Praemonitus (talk) 19:25, 25 September 2020 (UTC)
 * Perhaps we could add an arrow to highlight Proxima's location? TheWhistleGag (talk) 05:34, 27 September 2020 (UTC)
 * There are several image in Commons with markers pointing out Proxima. Lithopsian (talk) 10:17, 27 September 2020 (UTC)

Origin and age
Proxima was a pre-existing star that was captured by the Centauri A.

https://www.researchgate.net/publication/316193303_The_Composition_and_Evolutionary_Status_of_Proxima_Centauri

Hcobb (talk) 19:53, 4 January 2021 (UTC)


 * Yes, this hypothesis is mentioned in the article. Praemonitus (talk) 22:54, 4 January 2021 (UTC)
 * What isn't mentioned is the recently measured age and composition. Hcobb (talk) 02:29, 6 January 2021 (UTC)
 * It's rather indirect evidence, since the composition is being derived rather than directly measured. But yes it's probably still worth a mention in the same paragraph. Praemonitus (talk) 18:19, 6 January 2021 (UTC)

I attempted to add the following comment:
 * A 2017 study used evolutionary models to estimate the metallicity of this star, and found a composition that differed significantly from that of the Alpha Centauri pair: −0.5 < [Fe/H] < −0.3. The result is more consistent with an age of 7 to 8 Gyr, suggesting an independent origin.

with this reference:

but received a Wikipedia warning:
 * Warning: An automated filter has identified this edit as introducing references to a predatory open access journal or publisher. Predatory open access publishing is considered self-publishing due to lack of peer-review and predatory journals are rarely, if ever, appropriate for inclusion in Wikipedia. If you are confident that you want to cite this source anyway, please click 'Publish changes' again. Note that citations to predatory journals are routinely removed.

Thus I'll have to oppose adding that. We'll need a better reference. Praemonitus (talk) 19:44, 6 January 2021 (UTC)
 * American Journal of Astronomy and Astrophysics. Lithopsian (talk) 19:49, 6 January 2021 (UTC)
 * Well that probably explains why the paper wasn't included on the SIMBAD page. Interestingly, the paper by Beech et al. (2017) was referenced by the Feng & Jones (2018) cite already used in this article. Their comment:
 * The question of the evolutionary history of the alpha Centauri system and in particularly the metallicity for Proxima has been recently addressed by Beech et al. (2017). They find a best match for Proxima to have a metallicity of [Fe/H]= −0.5 or by constraining a simultaneous fit with the values of mass and radius used by Kervella et al. (2017) a metallicity of [Fe/H]= −0.3. However, there are a number of uncertainties involved and a metallicity as high as solar is allowed within their one-sigma error bars when considering a mass-radius relationship based on absolute K magnitude. There are a number of recent derivations of spectroscopic metallicities for Proxima showing a spread around a solar-like value, e.g., -0.07±0.14 (Passegger et al. 2016), 0.05±0.20 (Kervella et al. 2016a).
 * Praemonitus (talk) 22:25, 6 January 2021 (UTC)

Confirmed vs. Unconfirmed
Since Proxima c hasn't been clearly detected, its not officially confirmed, it's regarded as unconfirmed and needed to be edited to be a member of unconfirmed exoplanet candidates. Proxima c is just a strong candidate that has yet to be officially confirmed. — Preceding unsigned comment added by 71.214.105.58 (talk) 15:57, 24 June 2021 (UTC)