Talk:Gliese 581

Embargo

Hey eager-beavers, please respect the embargo. It's only another 6 hours. Vegasprof 17:38, 24 April 2007 (UTC)

Exactly what happens in 6 hours (from your post)? GoogleMe 18:26, 24 April 2007 (UTC)

There is news about a "new" Earth-like planet in this star's planetary system, see for example [1]. /195.58.126.131 18:32, 24 April 2007 (UTC)

Not exactly. Now it's four hours and two minutes. I put up a notice of this newly discovered planet on this page yesterday. The news was "embargoed," meaning that the press release was sent to media with a request not to print it until 19:00 ET today, which is four hours from now. One of the administrators deleted my post, and told me the situation, which I know fully understand and agree with. It's up to the discoverers to time their press release, and it was not nice for just a few papers to breach the embargo; the news was sent to them as a courtesy, so that they could ready their presses, or whatever. Anyway, despite the intense excitement about this story (which has already leaked to the Extrasolar Planets Encyclopedia) I think we should be polite and respect the embargo. Vegasprof 19:06, 24 April 2007 (UTC)

OK, I didn't fully understand that. Maybe it was an idea to prevent an article related to such an embargo from being updated by "locking" it? /195.58.126.131 19:12, 24 April 2007 (UTC)

Right. It has nothing to do with Wikipedia. But Wikipedia (as I understand), as a matter of courtesy, does not want to breach news embargoes. Vegasprof 19:18, 24 April 2007 (UTC)

19:00 ET probably refers to european time, i.e. it means 17:00 UTC, or 13:00 EST -- Stereo ^(talk) 21:45, 24 April 2007 (UTC)

Eastern, Central, or Western European time? If it was 17:000 UTC, the news would have appeared on the ESO website. CNN did have the news, but they removed it. So ET has to mean EST.— JyriL ^talk 22:04, 24 April 2007 (UTC)

Embargo is up now. Thanks for respecting the embargo - I removed the information as a courtesy, and I'm glad it was respected in the main. Daniel Bryant 01:24, 25 April 2007 (UTC)

The question is know, does this life really have the correct atmosphere to support human life, I heard that the planet could sometimes get up to 160 degress, and as low as 25 degress below zero. Are these conditions right for the inhability of humans, or are the difference in temperatures to extreme. Of course the real answere lies within how far our technology has gone, and is the CIA hiding something from us, and im sorry for sounding repetitive, but there still is the theorry about area 51. Let the people know

Data

The Extrasolar Planets Encyclopaedia has the data available for the planets c and d.[2]— JyriL ^talk 22:06, 24 April 2007 (UTC)

The chart says the planets are in order by distance from the star, but aren't they actually in order of discovery? Egamble928 02:00, 25 April 2007 (UTC)

In this case, the order is same.— JyriL ^talk 16:15, 25 April 2007 (UTC)

Earthlike?

A planet far more massive than the earth, orbiting a much dimmer star than the sun, in 12 and some days.

Maybe it's near earth temperatures. Maybe it isn't.

Is this news? Is this accurate? Does wikipedia want to go here? —Preceding unsigned comment added by 66.18.209.190 (talk • contribs) 25 April, 2007

Actually, it IS news. I just saw it on the news here in Holland and I have read a (Dutch) article about it in the Volkskrant, a big daily newspaper here. There is talk about whether there could be live on this planet, since it is earth-like with moderate temperatures (between 0 and 40 degrees Centigrades) and the possibility of the existence of liquid water on the planet. MarioR 10:26, 25 April 2007 (UTC)

Extraterrestrial skies

What would one see in the sky when Gliese 581 b makes a transit of the sun (Gliese 581)? Would it appear as a dot over that sun, or would it completely eclipse the sun? Our sun, of course, would appear in the constellation Cetus. GBC 15:49, 25 April 2007 (UTC)

You mean, what would it look like from 581 c? A dot. Our sun and our moon each appear to cover half a degree of arc in the sky. Gliese 581 is roughly 0.4 times as big as Sol, but only 0.07 times as far from 581 c, so it appears quite large, 2.85 degrees of arc, about 5.7 times as big as Sol seen from Earth. 581 b, 0.003 times as big as Sol, when transiting, would be about 0.03 AU from 581 c; if Neptune-sized, that means 0.05 degrees, a tenth as big as the moon seen from Earth, a sixtieth of the size of Gliese 581. (If that eccentricity figure for 581 c in the table is right, though, 581 c gets much much closer, even crossing the orbit of 581 b, so b could appear much larger in the sky shortly before c's doomsday.) Also, if b is rocky rather than gaseous, it would be visually smaller still, say about 2/3 that size. Going to render it? Kaleja 18:34, 25 April 2007 (UTC)

Answered that, ten years too late, but stil...

NelsonWins (talk) 23:16, 21 July 2017 (UTC)

Warp 5

88 days, not too shoddy, right?

I make it 60 days (365 * 20.5 / (5*5*5)) but at any rate, I haven't gotten my warp drive working yet. Kaleja 18:37, 25 April 2007 (UTC)

Eccentricity

The table on the Gliese 581 page gives a very high eccentricity of 0.3 for c's orbit; the page for Gliese 581 c gives eccentricity 0. Eccentricity 0.3 for a semimajor axis 0x 0.073 AU puts perihelion at about 0.039 AU if I got my math right; this is inside the orbit of Gliese 581 b, so I'm guessing that Gliese 581 c is more right than this page. Anyone have more info? Kaleja 18:14, 25 April 2007 (UTC)

Udry et al. give the choice between 0.0 and 0.16 for $e_{c}$ (Table 1 on p. 4 in the preprint). Are we going to describe the circular case, the eccentric case or both? —xyzzy_n 20:05, 25 April 2007 (UTC)

The .3 came from me, but it was wrong. But it looks like .16 +/-.07 is right, that is the same on exoplanets encyclopedia. Sorry for the error, I was trying to sync up the page with 581 c and I was usign data someone else had posted. Looks like it is all straightened out now. Also it appears all the data matche's exoplante encyclopedia, should we cite them as the source? I think we should cite something. Rich.lewis 16:27, 27 April 2007 (UTC)

I took the data from the Udry et al. paper (with some rounding). We already cite it. —xyzzy_n 23:19, 27 April 2007 (UTC)

Age of the system ?

I can't find any estimated age of the star or planetary system. Age is of course relevant when considering the chances of life on the planet.

Yes, this is very important. In particular, it could take a billion years for a red dwarf star to 'settle down.' Yesterday, while compiling information for this article, I ran across the statement (in a reliable source) that Gliese 581 is 4.3 billion years old. I don't remember where I found it, but I can probably find it again. Vegasprof 00:07, 26 April 2007 (UTC)

The Urdy et al. 2007 Astronomy & Astrophysics pre-print discovery paper gives the age (but notes uncertainty of +- 1 Gyr). Michaelbusch 00:10, 26 April 2007 (UTC)

I found the age on exoplanets encyclopedis here, [3], but they reference a source article from the journal of astronomy and astrophysics. However, only the abstract is available without a subscription. The original source is cited as "The HARPS search for southern extra-solar planets, V. A 14 Earth-masses planet orbiting HD 4308" S. Udry1, et al. I can't verify the original source so I just added a citation to expolanets encyclopedia. Is that good enough? Should we cite the original source, even though we can't verify the citation (without a subscription to the journal)? I guess citing the exoplanets encyclopedia is better than nothing. Rich.lewis 16:21, 27 April 2007 (UTC)

It seems to me that HD4308 is not Gl581, and an other article about Gl581 gives 2 billion years to the age. I wrote to the editor of the exoplanets encíclopedia - no response.--157.181.47.247 15:19, 10 May 2007 (UTC)

I saw the figure 4.3 billion years in russian wiki. The source of it is absolutely uncertain. 2 bln years? What is this article you pointed out?--Beaber (talk) 22:43, 2 October 2010 (UTC)

Nearby Stars

I was hoping this article could point me to a list of other nearby stars. Mathiastck 07:05, 26 April 2007 (UTC)

Try http://www.solstation.com. GBC 15:56, 26 April 2007 (UTC)

Or try Lists of stars, or List of nearest stars — Jack · talk · 17:02, Thursday, 26 April 2007

Pronunciation and rank

Two questions: How do you pronounce the name of this star? And in terms of ranking amongst all other stars, how far away is it? — Jack · talk · 17:16, Thursday, 26 April 2007

OK, so it's pronounced [ˈgliːˌzə] — which is "glee-zer", right? — Jack · talk · 18:25, Thursday, 26 April 2007

Depends on your local dialect of English. Rhymes with "Condoleezza" for all speakers. 24.20.137.228 13:55, 28 April 2007 (UTC)

It's a German surname, so check German phonology. I'm Finnish so I don't know. :)

581 is the star's ID number in Gliese Catalogue of Nearby Stars, compiled by astronomers Wilhelm Gliese and Hartmut Jahreiß. Star's ID in that catalogue is GJ 581 (GJ meaning Gliese-Jahreiß).

Stars have many names (catalogue ID's) so you may want to check SIMBAD database for others. In most of the Europe this star was known as HO Librae but that name is somewhat problematic in the English speaking world. :)

-- 212.213.204.99 18:54, 26 April 2007 (UTC)

At the distance of 6.28 pc (20.47 ly) Gliese 581 is the 87th closest star system.[4] — JyriL ^talk 21:57, 26 April 2007 (UTC)

Thankyou very much, JyriL :) — Jack · talk · 01:58, Sunday, 29 April 2007

Image

I realise quite well that ‘Celestia isn’t reality’. However, so far I’ve found only one image of the star which is real ( and that image is copyrighted and non-free. As for other images, I don’t see any advantage of the non-free art of Image:Phot-22a-07-normal.jpg versus some similar image made with Celestia that would justify using the non-free image. —xyzzy_n 23:39, 27 April 2007 (UTC)

I'd prefer a chart of some kind. An image of the star, unlabeled, is not particularly useful (it is just a point), although Sinbad would give you the necessary images under fair-use license. I'd really like the periodograms of the Doppler shift measurements, but those are in Udry's jurisdiction. Michaelbusch 02:40, 28 April 2007 (UTC)

Image:Phot-22a-07-normal.jpg is problematic not only in that it seems unlikely that any conjunction of those planets with a camera could produce that particular image but also in that the colors are all wrong. The star is far too red. Red dwarfs are "red" like camp fires or tungsten lamps, not like fire trucks. Even if the star looked like that, where is all the white light illuminating the planets coming from? 24.20.137.228 14:17, 28 April 2007 (UTC)

There is enough blue light being emitted that human eyes would adjust colorsense to compensate. That said, the disc of the star should then appear white except at the limb. Michaelbusch 15:58, 28 April 2007 (UTC)

What we really need now is a simple diagram of the orbits of the different planets.--Pharos 02:08, 29 April 2007 (UTC)

I agree with Pharos — Jack · talk · 02:41, Sunday, 29 April 2007

Okay we have a diagram up. Fusion7 15:37, 13 June 2007 (UTC)

Only "low mass" planet in a habitable zone?

There seems to be some question about whether this is or is not the first exoplanet in a habitable zone. No other examples are listed in the habitable zone article or any other reference I've seen yet. I think a sentence saying "this is notable because ..." should be as simple as possible, and if extra qualifications like "low mass" or "rocky" are necessary we should know what the "high mass" or "gaseous" examples are. 24.20.137.228 04:57, 29 April 2007 (UTC)

UPDATE: Astrophysics professor Greg Laughlin says HD 73526 c is a "room temperature gas giant" and HD 100777 b is "squarely in the habitable zone of its parent star". Somebody/me/whoever should probably mention something about these planets in Habitable zone. 24.20.137.228 12:55, 29 April 2007 (UTC)

UPDATE: apparently there are three Earthlike planets in this system, one at the inner edge and one at outer edge of goldilocks zone, and one - Gliese 581 g - right about in the middle. —Preceding unsigned comment added by Jvol (talk • contribs) 04:29, 30 September 2010 (UTC)

What happened to 581a?

This article lists three planets, 581b, 581c, and 581d. Why was "a" skipped? Nik42 20:57, 25 May 2007 (UTC)

581a is skipped, as it can also mean the star itself. Anarchist42 21:08, 25 May 2007 (UTC)

Ah, okay. What a strange convention. On a related note, are the letters assigned in order of discovery rather than distance? Nik42 01:36, 26 May 2007 (UTC)

Order of discovery. Sagittarian Milky Way 01:03, 10 June 2007 (UTC)

There are many...

There are about 12 planets with Earthlike temperatures, and these are massive enough to have Earth's mass moons that could hold life.Gliese 581 c is overhyped, this planet will be almost certainly very hot.Using these blackbody calculations, you will get temperature -20 degress Cellsius for our Earth.

Bias?

This edit seems to have been made by someone with a bone to pick against exoplanets in general and this one in particular. For example, saying that: 'Another fairy tale is possibly more appropriate to current exoplanet studies, termed the "Emperor's New Clothes Effect" ' certainly seems to me like this person has a bias against "current exoplanet studies". Can there at least be reliable citations to back up this part of the article? 4.245.224.8 03:19, 13 June 2007 (UTC)

Interesting comment considering the original article stated that Gliese 581 c is both 50% larger than the Earth and also that it is rocky when it is scientifically impossible to give that evidence at present, let alone reference it. It's a circular argument. If the radius is like that, the density of an object of that mass must surely be that of rock, if it's rocky, then it'll be 50% bigger than Earth at that mass. No reference was given for those statements in the original article.

In fact the whole original entry was riddled with super Earth bias of which there is little or no evidence even in the published scientific papers. Look at a solar system illustration placing earth adjacent to Neptune in terms of size, and imagine this third of a neptune minimum mass object , 5 x earth's mass, between the two.

It's simple. Wikipedia's own Spectroscopic binary data gives clues to how radial velocity work is done. Mass limits so derived are lower mass limits. They cannot be true in this instance as the object does not transit... ...unless a very recent press release on MOST satellite says different when the actual paper comes out.

Most exoplanet hype from the institutions is just that, hype. There is little independent confirmation except for the handful of transiting objects, most of the values have large scatter on their errors, including the distances, and the best fudged numbers are given. Most of the statements in the wikipedia entry on c were not referenced directly.

I'm not so much biased as anti-biased, or biased squared if you prefer. You've taken a propoganda bias and quoted it verbatim. Most of the data does not support statements as _exact_ as those made. I know encyclopedic entries are more general and not as specialised as niche and dedicated articles, but as the mass, size and nature of this object is purest speculation even given the formal data, noises about habitable zones and frost lines are perforce speculation based upon speculation. The only known Goldilocks Zone is in the Solar System, evidently this extrasolar system of Gliese 581 is not like the calibrating Solar System in anyway.

When it comes to reference the situation here is that the original statements had little specific reference to each attested fact anyway, whereas the points that can be pointed out as wrong are general facts, not usually referenced. For instance, SB1 spectroscopic binaries have their masses quoted as a ratio, an inclination dependent ratio, relative to the mass of the primary. Single red dwarf stars have their masses assumed, not measured, via a luminosity relation that is not the same for red dwarfs as other main sequence stars, and carries several differing values in the literature. The apparent magnitude and the parallax of this object, Gliese 581, are well known enough for an absolute magnitude to be derived, and thus the luminosity. Which mass relation is then used? Further, it may be that there are two such relations for red dwarfs, as can be seen by differing absolute magnitudes for differing objects, for example Proxima Centauri and Barnard's star, which are likely listed in wikipedia. And yet some assumption on this mass is taken for the red dwarf, that is used with the radial velocity data to assume a minimum mass for object c, which in itself is not the real mass as then it'd be at 90 degrees inclination, and thus eclipsing/transiting. Etcetera, etcetera, standard, general principles, stuff. This could shift the object's mass all over the place, if proper error ranges are considered. Therefore, Emperor's New Clothes. The original article carried the unfounded bias.

Finally, it is interesting to note that the similar generalized, not rigorously referenced, comments and changes I made with respect to the fact Gliese 581 is in fact not variable, despite what the reference catalogues say, was not excised for bias, likely because it makes the case for "life" out there more feasible. Feh.

Whatever, do what ya want, it's your wiki. Just don't accuse something assessing the bias of massive unsubstantiated speculation being passed off as concrete fact as being bias itself. How can you disprove something that is itself unproven? As the saying goes "it's not even wrong".

86.137.132.151 22:23, 13 June 2007 (UTC)

I agree that, with our current technology, anything that humankind can say about other solar systems and the planets within them is, at best, based on educated guessing and speculation. However, I think that this is implicit in the fact that we are talking about heavenly bodies several light-years away. Upon close inspection of your edit (and your defense of it up above), you seem to be saying that we cannot be sure of the exact details (mass and radius) of Gliese 581c, generally because of the fact that we probably do not lie in its orbital plane (and thus cannot observe it in transit, like we can with, for example, Venus) and because we are not very certain of the mass of its parent star (because it is a guess based on luminosity).

You also seem to be familiar with the mathematics behind these astronomical observations. If you can rewrite your edit in clear and simple terms that a plebian such as myself can understand, and add citations which can back up what you say when you can do so (for example, why it is not reliable to assume mass given the luminosity of a red dwarf star), and put it in a way that is neutral as to the possibility of life being there (which you seem to be against), and write it in such a way that it doesn't look like original research, then that would be a whole lot better and I won't delete it the next time I'm "being bold". Or better yet, maybe you can start an article about uncertainty in exoplanet studies or something to that effect.

As far as not reverting your other edits - sorry, I'll be more of an ad hominem Nazi next time. ;) (just kidding) And it's not my wiki - it's our wiki, it belongs to the world. (the world of humans, I mean) 4.245.149.216 11:13, 14 June 2007 (UTC)

Peak wavelength?

Are there any spectra of Gliese 581 available from which we can get an empirical value, as opposed to assuming the star is a blackbody (an approximation that isn't too good for cool stars)? Chaos syndrome 19:14, 28 August 2007 (UTC)

The paper that is referenced to in wikipedia is evidently taking the star to be a black body hence the values quoted for the bolometric luminosity within it.

Cooler stars are more prone to stray from a black body proximation in their continuum due to molecular absorption bands, but for a red dwarf this should be relatively insignificant. Hopefully.

How would you ascertain this peak wavelength? It would not just be the highest bit of the plot, or the most intense wavelength if there were emission peaks, for instance.

81.129.250.131 18:19, 2 September 2007 (UTC)

Luminosity value

We seem to have an issue with a user (I assume it is one user with two IP addresses from the content of the edit summaries)

I have a dynamic IP, there's nothing I can do about that (I'd actually forgotten, too). 81.129.250.131 18:48, 2 September 2007 (UTC)

Maybe consider registering as a user here, makes some things easier. Chaos syndrome 19:53, 2 September 2007 (UTC)

who is insisting on changing the value of the luminosity from the quoted value in the literature to a value calculated by that user. The values differ by only 0.1% of the solar luminosity (literature value=1.3%, user's value=1.2%). Already this is pretty good agreement, and looking at the von Bloh paper "Habitability of super-Earths in Gliese 581" it appears the error on the quoted value is 0.2% of a solar luminosity anyway, so the values derived are essentially identical. Since the user's calculation supports the literature value (the discrepancy is probably negligible within the error margins anyway), I suggest we go with the literature luminosity as we can provide a verifiable citation to this value. Chaos syndrome 22:55, 30 August 2007 (UTC)

The difference is probably negligible, so the point is somewhat valid, as it is within the errors, however the relationships between the values are nonlinear, so small amounts can matter. Likely in this case, however, the nonlinearity makes the difference even more insignificant. It is sad, however, for an information resource to list values in a data box and note another value that is at odds with one derived from those values.

The more important points are two:-

i) Another reference (number 6), to the Bloh paper propagates the constant falsehood with respect to the mass of these planets. Only if this was an eclipsing/transiting system with an inclination of 90 degrees could the mass limits for the planets be valid. As such they are lower limits. The planets are more massive than that. Conjecture about surfaces and the like are mere conjecture, there is no evidence of any kind to state what the atmosphere or nature of these objects are, they could be big lumps of rock, they could be small, not mini, but small Neptunes, they could be Jupiters. There is absolutely no way of knowing with current data.

ii) The Bloh paper has no more academic validity than a blog entry. It states nowhere as to whether it has been either submitted and/or acceptable by a mainstream scientific journal, or any journal at all, and therefore it is not peer reviewed, and therefore I repeat it has no more validity than a random blog entry. Anyone can upload a paper to arxiv if one or their friends and/or associates is willing to endorse it, which is not the same as peer review, more like favours between pals. Checks in ADS abstracts search reveal the paper exists nowhere else. Great care has to be taken when using arxiv preprints are references. Until they are logged as having been accepted by a peer reviewed journal they are not standard accepted by the scientific community articles, they are just thoughts and opinions. It is interesting to note that the Bloh paper has a version one upped in May, and now a version two recently upped, yet still only existing as a fancy styled blog entry, there having apparently been no attempt to submit it to standard scientific publishing scrutiny inbetween times.

81.129.250.131 18:48, 2 September 2007 (UTC)

Regarding the von Bloh paper, the Extrasolar Planets Encyclopaedia lists the reference as being submitted to Astronomy and Astrophysics - see the references list here. Furthermore, a Google search reveals that the authors do have peer-reviewed publications in related areas (e.g. Werner von Bloh's publication list), so this isn't the case of some randoms submitting a non-reviewed paper to arXiv and thus gives it more validity than a random blog entry IMHO. Furthermore, what seems to be going on here is a combination of various different methods to determine the luminosity: while a given bolometric correction relationship may be good for statistical samples, it is not necessarily applicable to an individual star. Other determinations of the bolometric correction may give different results: for example, from the absolute bolometric magnitude given in Delfosse et al. 1998, I calculate a luminosity of 0.014 times solar. In any case the luminosity value and the magnitudes in the infobox are not inconsistent, as we have not specified the bolometric correction. Chaos syndrome 19:53, 2 September 2007 (UTC)

North?

The first paragraph, as of this date, includes the phrase, "It is about two degrees north of beta Librae . . ."

I've seen locations of celestial bodies described in this way before and have never understood what that meant. I decided to try to make a link in the above phrase as a way of educating myself, but was unable to discover (within Wikipedia, at least) an adequate explanation to which I could link. I found the Celestial pole article, which provides some context but doesn't provide a satisfying layman's explanation for how a celestial body could be described as being "north" of another celestial body, and what the "degrees" are. I assume that it has something to do with the axis around which earth-bound observers perceive the heavens to be rotating, but that's an assumption on my part and represents the extent of my education on the subject.

Part of my problem is that I don't have an adequate search term. I don't know what that system of notation is called, so I can't search for it by name. Can someone out there with a knowledge of astronomy help me (and, likely, other readers)? Perhaps Wikipedia already has an article on this subject but I've been unable to find it. —CKA3KA (Skazka) (talk) 22:22, 29 November 2007 (UTC)

'North of' means in the same direction to the north as geographical along the sky, pointing towards the north celestial pole. BlueEarth (talk) 00:37, 30 November 2007 (UTC)

Name of the Star?

I've just been doing a bit of research into Gliese 581 and have found that the star is also referred to as Wolf 562, so why is this alternate name not listed in this article? I know that all other star articles list all the other names, but I don't see this one here, so why not? (for confirmation of the name check out this page: [5]) --Hibernian (talk) 00:03, 7 February 2008 (UTC)

Ok since on one has said anything for ages I've just gone ahead and done it, because I'm pretty sure about it. If it is for some reason incorrect, then please say so. Also it would be an idea to turn Wolf 562 into a redirect to Gliese 581. --Hibernian (talk) 17:13, 30 April 2008 (UTC)

I like names which give the constellation. I think Wikipedians like them too, c.f., mu Arae which is usually called HD 16something in the astronometric world. This one is HO Librae, so, I'd prefer that. Otherwise, if there is a cartographical preference for Wolf 562, then point out where it's used. Maybe these aliases should just be deleted and left to the starbox... -- Zimriel (talk) 19:54, 20 August 2008 (UTC)

HO Librae is a variable star designation. Furthermore the current way things appear to be working is to give preference to Bayer and Flamsteed designations over catalog numbers, but this does not appear to apply to variable star designations, and in any case HO Librae is not used in news articles pertaining to this star (seems to be almost universally referred to by the Gliese number in such sources). Furthermore there is the argument that since the star is not variable, the variable star designation should not be used. I moved it out of the lead paragraph for this reason. Icalanise (talk) 18:52, 6 October 2008 (UTC)

Distance discrepancy

The Astrometry info box gives the distance as 19.9 ± 0.3 ly, whereas the opening paragraph gives the distance as 20.5 light years. Which, if either, is correct? Can someone please correct it.HumphreyW (talk) 11:38, 11 October 2008 (UTC)

The distance in infobox as 19.9 light years is the right one, I will change it. BlueEarth (talk) 19:30, 11 October 2008 (UTC)

And now the infobox says 20.3 ± 0.3 ly, and the opening paragraph has "about 22 ly". If it is between 20.0 and 20.6, that is not "about 22". If you had to round it off to an integer you'd surely go with 20, right? Direvus (talk) 12:11, 19 August 2013 (UTC)

GA Review

This review is transcluded from Talk:Gliese 581/GA1. The edit link for this section can be used to add comments to the review.

Hi! I will be reviewing this article for GA status, and should have the full review up soon. Dana boomer (talk) 16:47, 20 October 2008 (UTC)

GA review (see here for criteria)

1. It is reasonably well written.

   a (prose): b (MoS):

   • The lead should be a summary of the entire article, with no original information, and therefore doesn't need references unless they are backing up a direct quote.

   • done Nergaal (talk) 20:54, 20 October 2008 (UTC)

   • In the first paragraph of the Planetary section, can you give the names of the planet when you first introduce them, please. Also, would it be possible to put all of the information on each planet together? Currently, you go from planet b to planet c to possible planet d back to planet b to planet c to planet d and back again to planet b. This gets a little confusing...

   • done Nergaal (talk) 20:54, 20 October 2008 (UTC)

2. It is factually accurate and verifiable.

   a (references): b (citations to reliable sources): c (OR):

   • Several areas need references:

   • Star section, all of 1st paragraph

   • done Nergaal (talk) 20:54, 20 October 2008 (UTC)

   • Planetary section, last half of 1st paragraph

   • done Nergaal (talk) 20:54, 20 October 2008 (UTC)

   • Planetary section, last sentence of section and table

   • done Nergaal (talk) 20:54, 20 October 2008 (UTC)
   • why does the table need refs if the data is reffed in the subarticles? Nergaal (talk) 19:07, 20 October 2008 (UTC)

   • Because Wikipedia itself is not a reliable source; therefore, you cannot use information from other WP articles, even if sourced, as a source for information in this article. This is mainly as a check against the ever-changing nature of Wikipedia. If the information is already referenced in another article, it should be easy enough to import the sources to this article. Dana boomer (talk) 19:30, 20 October 2008 (UTC)

   • done Nergaal (talk) 20:54, 20 October 2008 (UTC)

   • You need to either always use cite templates or never use them.

   • this is definitely not a GA requirement. Nergaal (talk) 19:17, 20 October 2008 (UTC)

   • No, it's a general WP thing. See Wikipedia:Citing sources, where it says, and I quote, "Any of these styles is acceptable on Wikipedia so long as articles are internally consistent.", when referring to referencing styles. I'm not saying that you have to use cite templates (I prefer them, but it's an opinion thing), I'm just saying you have to be consistent in either using them or not. Dana boomer (talk) 19:30, 20 October 2008 (UTC)

   • done? Nergaal (talk) 20:54, 20 October 2008 (UTC)

   • Ref #4 needs a publisher

   • done Nergaal (talk) 20:54, 20 October 2008 (UTC)

   • Please spell out the publisher in ref #10

   • done Nergaal (talk) 20:54, 20 October 2008 (UTC)

   • Please make sure that you have the publisher, not just the work. For example, the publisher of ref #11 would be Imaginova Corp, while SPACE.com would be the work. See also refs 14, 15, 17 etc.

   • space.com is the publisher Nergaal (talk) 19:23, 20 October 2008 (UTC)

   • No, it's not. Space.com is the work. It is a brand of the publisher. If you scroll down to the very bottom of the page, you will see that it says copyright Imaginova Corp. And if you click on the "about us" button (also at the very bottom) you will be taken to a page describing Imaginova and their brands (of which space.com is one). The website did not publish itself, it was published by a company or an individual, and in this case it was published by Imaginova. Dana boomer (talk) 19:34, 20 October 2008 (UTC)

   • If you're going to use the split ref formatting for journal articles (like you have on the Selsis et al. article), you need to do it for all of them. On the other hand, you could just turn the Selsis article into the full in-line ref format like the rest, which would probably be easier.

   • done Nergaal (talk) 20:54, 20 October 2008 (UTC)

   • How are the last four sites in the references section used as references? If they cite specific parts of the article, they should be put inline - if they are just general information, put them in the external links section, or remove them if they are not applicable.

   • done Nergaal (talk) 20:54, 20 October 2008 (UTC)

   this section should be done. Nergaal (talk) 19:33, 20 October 2008 (UTC)

3. It is broad in its coverage.

   a (major aspects): b (focused):

4. It follows the neutral point of view policy.

   Fair representation without bias:

5. It is stable.

   No edit wars etc.:

6. It is illustrated by images, where possible and appropriate.

   a (images are tagged and non-free images have fair use rationales): b (appropriate use with suitable captions):

7. Overall:

   Pass/Fail:

I have a few concerns with this article, mainly with referencing, so I am putting the article on hold until these issues can be addressed. Drop me a note here on the review page or on my talk page if you have any questions. Dana boomer (talk) 17:17, 20 October 2008 (UTC)

Everything looks good, so I am going to pass this article to GA status. Nice work! Dana boomer (talk) 21:48, 20 October 2008 (UTC)

Undiscovered planet in resonant zone?

In reviewing the planetary chart for this system, its obvious that there is a significant gap between the two outer planets that should allow for a fourth planet in between under the Titus-Bode Resonance Law (which essentially says that each planet should be twice as far from its primary as the next inner planet, on average). Is there any research on this issue that anybody can find?75.67.80.68 (talk) 01:15, 20 December 2008 (UTC)

Possible fourth planet in Titus-Bode Resonance?

the gap between the outer two planets is significant enough that under the Titus-Bode Resonance Law (which essentially says that the distance of a planet from its primary should be twice that of the next inner planet, with some adjustments for mass) there should be a fourth planet between the two outer planets, and which also puts it smack dab in the middle of the habitable zone. As it is as yet undetected, this could be a terrestrial earth-like planet, if it exists. Is there any research out there we can find that would support or disprove this possibility?75.67.80.68 (talk) 01:21, 20 December 2008 (UTC)

Could be an asteroid field. Like the one we have that between Jupiter and Mars. HumphreyW (talk) 05:20, 20 December 2008 (UTC)

• Heeeey, look what just happened! Zazaban (talk) 20:42, 21 April 2009 (UTC)

Variable star

I removed the second paragraph of the "Star" section of this article as it is merely an argument against a previous version of this paragraph that identified Gliese 581 as a BY Draconis variable type variable star as it is appears in the latest (2008) version of the General Catalogue of Variable Stars (search Gliese 581).[6] The author of this latest paragraph rewrite wants to minimize the variability of this star to improve the star's theoretical habitability. One reference he quotes is unavailable and the other is a just collection of raw data. We should stick to the variable star classification until SIMBAD and other recognized databases officially reclassify this star. I am not opposed to restoring the original paragraph, or adding a new section on new published research concerning the variability of this star, if any. Aldebaran66 (talk) 04:54, 22 April 2009 (UTC)

I see nothing wrong with quoting what both SIMBAD and the Mercedes paper says (in the spirit of WP:Verifiability even if they are both wrong). But I looked at the 11 June 2007 diff you helpfully gave above and it seems neither version (before or after the edit) is good enough. The "before" revision first correctly claimed GL 581 is classified as a BY Draconis, but also incorrectly claimed it varies by up to 0.5 magnitudes, followed by a cite from Mercedes Lopez-Morales (arxiv.org/abs/astro-ph/0609255) that states on page 2:

"GJ 581 (V* HO Lib), an M3V star, has been catalogued as a BY Draconis variable. ... Weis (1994) monitored GJ 581 over eight years and found seasonal and long-term photometric variations of 6 – 8 mmags in V, R, and I band."

6 to 8 mmags is only 0.006 to 0.008 magnitudes.

That revision then has "(Short-term variability is at most 0.006 magnitudes.)" citing a URL that returns Forbidden ([7]). The Mercedes Lopez-Morales paper contradicts this with "However, no short-term (in the scale of hours) variability measurements have been reported so far."

The "after" revision claims GL 581 is wrongly classified but uses [8] as a cite, which shows it classified as a "BY" with max = 10.56 and min = 10.58 (which would be 20 mmag variation). That same msu.su cite refers to "Weis, E.W. 1994, AJ, 107, 1135" which compares to "73018. E.W.Weis, AJ 107, No.3, 1135, 1994." used by Mercedes Lopez-Morales.

Maybe something like this sentence could be used, in a footnote to the infobox entry even?

Gl 581 is classified as a BY Draconis variable, but an eight-year study showed long-term variations of only 0.006 to 0.008 magnitudes and no reported hour-scale variability.< ref name="Lopez">Lopez-Morales, M.; Morrell, N. I.; Butler, R. P.; Seager, S. (2006). "Limits to Transits of the Neptune-mass planet orbiting Gl 581". Publications of the Astronomical Society of the Pacific. 118. Retrieved 2009-04-23.{{cite journal}}: CS1 maint: multiple names: authors list (link) (page 2 of pre-print submitted 9 September 2006)</ref>

84user (talk) 21:46, 23 April 2009 (UTC)

Thank you for looking in to this issue. It is reasonably important to consider whether this star is truly a variable star because of the impact variability has on habitability. And it is well known that red dwarf stars can be nasty little things.

I am reluctant to use Weis as a source without reading it first and that would mean a drive to UCLA. Even if this article supports the .006mag value this source is not readily accessible as the online database for AJ only goes back to 1998. I don't think we should rely on the citation in Lopez-Morales as it is second-hand and we know they are only concerned with hourly fluctuations that could affect their transit data.

I agree that the statement about .5mag variations does not apply specifically to Gliese 581 but is a general statement as to the maximum variation of BY type stars. I would prefer quoting the conservative 'max = 10.56 and min = 10.58' (20mmag) value that appears in the GCVS database. These values may also be from Weis as it is referenced here. How about this:

Gl 581 is classified as a BY Draconis variable in the General Catalogue of Variable Stars. This catalog gives a maximum magnitude of 10.56 and minimum of magnitude 10.58 for a relatively low 20mmag variability [9]. Other multi-year studies are said to show an even lower variability.< ref name="Lopez"></ref>

Aldebaran66 (talk) 02:25, 24 April 2009 (UTC)

Bonfils 2005 letter's first page is at [10] and the full article is available as this PDF, so I updated the existing URL in the article. I then read Bonfils page L16 section "2. Properties of Gl 581" and added a quote that also mentions 0.006 mag more directly than Lopez. Accordingly I have added variable=BY to the infobox with a footnote using your words, minus the "other studies" as I could only find mention of Weiss in connection with 0.006. Bonfils does mention other doppler surveys of M-dwarf stars: Bonfils 2004, Butler 2004, did you mean those? 84user (talk) 12:59, 24 April 2009 (UTC)

Once again, thank you for your help. I think the information that you have added is clear. Meanwhile I am going to try to get a reprint of the Weiss paper. I'll let you know what I find. Aldebaran66 (talk) 16:37, 24 April 2009 (UTC)

The Weis paper (AJ 107, 1135) is available [11] from the Astrophysics Data System; see [12]. This is the long-term study quoted by the GCVS. Also see Matthews 2007, p. 82. Spacepotato (talk) 03:14, 25 April 2009 (UTC)

RFC

I do not want to get into any war either, I just wanted to see a helpful caption, which was then supplied. However I now see the shown phase of the blue Planet b is not correct: it should be nearly full and not a half crescent. Its size is also exaggerated (in reality it would appear smaller than a pixel) but that could be mentioned in the caption (enlarged for clarity maybe?).

Why not discuss this and other artist images in Wikipedia:WikiProject Astronomy/Image Review? It is linked as a subproject of Wikipedia:WikiProject Astronomy but has seen no use after 2007. I have added this note to increase its visibility. 84user (talk) 21:31, 15 July 2009 (UTC)

An RFC over a content dispute? Seriously? Get over it and get on with improving things.
— V = I * R (talk) 21:43, 15 July 2009 (UTC)

The image is less ghastly and awful than this one, which has an even worse depiction of lighting. As for the apparent size of Gliese 581 b, on the scale of the system and assuming the planet is roughly Neptune-sized (not an unreasonable assumption given the similarity to Gliese 436 b), a visible disk is in fact perfectly reasonable from the vicinity of e. A larger size than a pixel is also plausible for planet c depending on where it is in its orbit. This would require that planet c is the one that appears furthest to the right. The real problem is that in reality the brightness of Gliese 581 itself would likely drown everything else out apart from the nearby planet and possibly planet b. It wouldn't appear nearly so dim and red from close up - the star is roughly the temperature of an incandescent lightbulb (using this as a reference), and would thus have a somewhat similar colour and surface brightness. Icalanise (talk) 21:27, 16 July 2009 (UTC)

The large bottom left planet simply cannot be b and the blue half-phase planet be c from the geometry of the orbits. Superior planets always show a gibbous phase, never a half or crescent. However the geometry works if the large planet is meant to be c and the blue half phase planet b. I have boldly changed the caption, in the hope the error was a typo. The left to right order now makes more sense: from the 5-Earth mass c at .07 AU from the star one could plausibly view the 15+ Earth mass (Neptune-like?) blue planet at 0.04 AU at half-phase; one could then see the distant d as fainter than the nearer e. The relative sizes are still not correct but closer to a possible reality. The "true" relative brightness is of course impossible to display on monitors, see What color are the stars? and Blackbody colors for why. The chroma of the image star is probably a bit too red but Ok for artistic license I guess; the star colours link gives this shade for Gl 725 A (another M3V red dwarf). 84user (talk) 09:18, 22 July 2009 (UTC)

I disagree with your assignment of the bottom left planet as c as it is clearly intended to be e judging by the description at the source page and given the Mercury-like appearance they are giving to the world. Furthermore your assignment makes the apparent size of planet e much too large, given the phase indicates it is on the far side of the sun from the viewer. The original assignment that the foreground planet is e makes the phase angle of b wrong (given the ratio of orbital radii, the phase angle of b as seen from e cannot exceed about 49 degrees, or 45 degrees if you rederive the orbital radii using Kepler's laws and the orbital periods to improve on the quoted precision of one significant figure!). The original caption states the large blue planet is in fact d, but this is ridiculous due to apparent diameter. Don't any of the space artists who produce such images have access to a decent raytracer to check the illumination??? I have thus been bold and removed the image entirely. Icalanise (talk) 21:51, 22 July 2009 (UTC)

Sorry, I made a typo in the description. I called the planet shown planet c, when it is supposed to be e. I fixed the type, sorry for that. — NuclearVacuum 15:37, 23 July 2009 (UTC)

I have mixed feeling on the image:(Shortcut to image on ESO site) But technically speaking the image is incorrect on the phases of the outer planets and I don't think it offers any educational value. Then again I doubt few people look at it that closely. But I do think it is possible that the naked eye would barely make Gliese 581 d out as a small round sphere since it is less than 0.28AU away from 581e. Their have been reports of people seeing the cresent phase of Venus (66″) and the naked eye has a resolution of 1–2′. Note the ESO image makes it clear, "planet d, with the bluish colour". -- Kheider (talk) 16:20, 23 July 2009 (UTC)

Well the image doesn't really work well as a view from any of Gliese 581's planets. The blue half-phase planet means that the foreground planet cannot be e, as the phase implies it orbits interior to the foreground planet. The blue crescent doesn't make sense as planet e (which is likely too small to be a gas giant), so assigning the foreground planet as b doesn't work too well either. Assigning the barren rocky world as being c or d also don't work well, as planet formation theory predicts planets like b (and therefore likely also the planets orbiting beyond it) formed in the volatile-rich regions beyond the ice line and thus should have a substantial icy component. And sad to say, this is one of the better artistic renditions put out with an exoplanets press release. Icalanise (talk) 20:19, 27 July 2009 (UTC)

Thank You

I'm an avid amateur astronomer and it brings tears to my eyes to see a picture at the bottom of the star system like the one for ours. It's amazing how our knowledge has grown. Looking at the picture, I honestly stopped feeling all alone out here in this corner of the universe. So, thank you to everyone who's let us understand this - including folks here on wikipedia. - Josh Shahryar —Preceding unsigned comment added by 68.45.80.204 (talk) 23:57, 25 May 2010 (UTC)

Gliese 581 e update

EPE has updated e, saying the orbit has changed and mass and stuff. I'm not sure what the #>m># means... so I'm leaving someone else to update it... Syntheticalconnections (talk) 21:19, 15 June 2010 (UTC)

Contradictory?

"...Gliese 581 c orbits just inside of the habitable zone of its parent star" and "Gliese 581 d ... orbits just inside of the habitable zone of its star": Surely they cannot both be "just inside of" if c orbits at 0.07 AU and d at 0.22 AU (that's ~21 million km further out). Especially as Gliese 581 d says "It was originally thought that Gliese 581 d orbits outside the habitable zone of its star. However, in 2009 the original discovery team revised its original estimate of the planet's orbital parameters, finding that it orbits closer to its star than originally believed. They concluded that the planet is within the habitable zone where liquid water could exist."

Then there's "Gliese 581 c ... is notable as it is the planet with lowest minimum mass yet discovered in the habitable zone of another star, making it the most earthlike exoplanet found to date.[18]" compared to "Gliese 581 e, ... at an estimated minimum mass of 1.9 Earths, is currently the lowest mass exoplanet identified around a normal star". Either c is in the habitale zone or it isn't and maybe it is the least massive or it isn't (c = 5.36 – 10.4 M⊕, e = 1.94 – 3.1 M⊕)

The individual planet articles seem better. 87.115.207.175 (talk) 19:22, 10 August 2010 (UTC)

Gliese 581 f and Gliese 581 g - Press Release from Keck Observatory - Release later removed

There was what appears to have been a premature press release from Keck Observatory at this address: http://keckobservatory.org/news/test2/ The url is interesting ("test2"?) but though the content has been removed, the page title still displays "Keck Observatory discovers the first Goldilocks exoplanet". When I initially retrieved the article, it indicated two new planets, with 581 g well within the habitable zone. Since they removed the release, I have undone my edit to the page. Woodega (talk) 20:57, 29 September 2010 (UTC)

The release is up again under a different URL: http://keckobservatory.org/news/keck_observatory_discovers_the_first_goldilocks_exoplanet/

Also, NASA has announced it: http://www.nasa.gov/topics/universe/features/gliese_581_feature.html

Returned my previous edit, with corrected URL.

I've also noticed an ambiguity or contradiction in what planets are where in the habitable zone. This Wikipedia article states that Gliese 581 d is "just inside the habitable zone," yet the release from Keck states that 581 g is in the middle of the habitable zone. Gliese 581 d has a period of 66.8 days, which would mean that it orbits outside 581 g's orbit, since 581 g's orbital period is 37 days. Should 581 d's information be changed to something like "just within the outer limit of the habitable zone"? I guess I'll do some more digging for accurate details. Woodega (talk) 22:35, 29 September 2010 (UTC)

Yes, I think your reformulation is just what is meant. Feel free to change. --Roentgenium111 (talk) 22:37, 29 September 2010 (UTC)

This preprint appears to have more info than was in the article before - http://www.ucolick.org/~vogt/ms_press-1.pdf Willhsmit (talk) 23:02, 29 September 2010 (UTC)

orbital chart needs replacement/update to include Gliese 581 f and Gliese 581 g

Chart labelled 'The Gliese 581 planetary system orbits.' (File:GJ581orbits.svg) is now out of date, as its missing both Gliese 581 f and Gliese 581 g. I don't have ability to update, haven't seen any new ones yet. I considered taking it down, since its a little confusing, but decided partial visual info was better than noting. replacing this chart would be very helpful. Jvol (talk) 04:37, 30 September 2010 (UTC)

I added g as a circular orbit. f would require a larger scale, better to make a second image? WELL, more care is needed to confirm the old image has the most up-to-date orbital parameters as well, since I just added to it! Tom Ruen (talk) 07:20, 30 September 2010 (UTC)

Thanks for adding g, though I would prefer it being given a non-circular orbit so that the orbits of g and d do not intersect. I doubt intersecting orbits would be very stable, and the NASA article's graphics [13] also gives non-intersecting orbits for the two planets. --Roentgenium111 (talk) 12:44, 30 September 2010 (UTC)

I will attempt to regenerate the orbital chart for the 6-planet solution. Given the range of semimajor axes it may be that the best solution is to view the system at two different scales, as I did for the view of the system of HD 10180. Incidentally you CANNOT take the eccentricities from the 4-planet solution and quote them for the same planets in the 6-planet fit. It is well-known property of multi-planet systems that unmodelled signals can manifest as extra eccentricity in the known planets, for example the 3-planet fit to the radial velocities for Mu Arae gave much higher eccentricities than the 4-planet fit. If we take the solution with 6-planets, the orbits of planets c and d should be taken as circular. Icalanise (talk) 22:31, 30 September 2010 (UTC)

Thanks Icalanise. I knew it was trouble to just drop in the new planet's orbit radius! Tom Ruen (talk) 22:40, 30 September 2010 (UTC)

For now I have updated the diagram to the 6-planet solution in Vogt et al. (2010). This is at least a better representation of the system than just dropping the circular orbit of planet g into the 4-planet solution. The full diagram incorporating the orbit of planet f (which is too wide to fit on the current diagram) is on my to-do list. Icalanise (talk) 23:09, 30 September 2010 (UTC)

Given the status of g/f has been moved to "unconfirmed", and old 4-body orbital chart restored, it was confusing, so I added BOTH orbital sets, 4-body, and 6-body for comparison. I also added back the old 4-body parameters, although the section ought to be reorganized to better explain these two depictions. Tom Ruen (talk) 12:24, 13 October 2010 (UTC)

Message from Earth

I removed this section, link didn't get to a clear source, and the only search matches I found were blogs quoting wikipedia! Tom Ruen (talk) 23:14, 30 September 2010 (UTC)

Seeing the article A Message From Earth, I relinked it, taking the openning paragraph from there for greater clarity. Tom Ruen (talk) 23:35, 30 September 2010 (UTC)

Message from Earth

In October 2008, members of the networking website Bebo beamed A Message From Earth, a high-power transmission at Gliese 581 c, using the RT-70 radio telescope belonging to the National Space Agency of Ukraine. This transmission is due to arrive in the Gliese 581 system's vicinity by the year 2029; the earliest possible arrival for a response, should there be one, would be in 2049.< ref>"Zimbio Pilot - Gliese 581c". Zimbio.com. 2008-10-13. Retrieved 2009-04-23.</ref>

Solar system analogues

The opening paragraphs describe planets c and d as Venus-like and Mars-like respectively. This is very speculative. There is no particular reason to assume that these planets are anything like Venus and Mars, or even that they are terrestrial in nature. They could easily have compositions dominated by ices rather than rock. This would make planet c completely unlike the extremely water-poor planet Venus, and provide d with a much more substantial atmosphere than Mars has. Just because a planet is located in an equivalent region of space doesn't mean it is an analogue of what we have in the same part of our Solar System. Icalanise (talk) 15:27, 2 October 2010 (UTC)

From what people know about planets, we are going to at first assume the way they are. Should >c space travel be possible, one day we may know we were wrong. But without much knowledge, I think it's fine to keep the "Venus-like". "It is suspected to have a runaway green house effect, like Venus." might work better? And the term for habitable planets is "Earth-like", I see nothing wrong with that. The "Mars-like" though, could be described as a cold rocky planet. atomic7732 15:37, 2 October 2010 (UTC)

Problem is we do not know that these planets are rocky, so "Mars-like" is extremely dubious. Icy composition is probably more reasonable given the planets' large masses and the obvious signatures of planet migration in the system architecture. That would result in planet d being nothing like Mars, but more like a less-frigid version of Ganymede. Icalanise (talk) 18:55, 2 October 2010 (UTC)

Those terms are the only way most laymen would understand what the paragraph is talking about. I think they are fine the way they are, but Atomic7732's versions would also be acceptable. Nutiketaiel (talk) 00:26, 3 October 2010 (UTC)

Rotational period of star

I didn't see this data anywhere, it's rather strange. Can it be explained somehow? It would be very interesting to add this information to article (if its possible, of course).--Beaber (talk) 05:16, 3 October 2010 (UTC)

... and visible stellar magnitude: 10,58 m (1982) → 10,57 m (1985) и 10,57 m (1985) → 10,56 m (1990). It becomes brighter, what's now (2010)?--Beaber (talk) 01:16, 4 October 2010 (UTC)

f and g retracted?

Both are unconfirmed on the EPE. atomic7732 23:26, 13 October 2010 (UTC)

Source for JD 2453152 for the four-planets solution

Please provide a source for the epoch JD 2453152 for the Mayor et al. (2009) orbits. The arXiv version lists some JD in Table 2 (actually Table 1 in the released paper due to a misnumbering in the preprint), but it remains unclear to what these refer, and none of them equals the value given in the orbit plot.--SiriusB (talk) 11:39, 2 November 2010 (UTC)

The orbital solution does not state an epoch and is in any case from a Keplerian model which does not include effects that would modify the orbits over time. The values of T in the table are the periastron times of the planets. Obviously it is necessary to choose some point in time in order to depict the planetary positions. For the various orbit diagrams I have uploaded to Commons I use the epoch from the source when one is available, but here the choice is an arbitrary one chosen to be fairly close to the start of the HARPS dataset for this star. Icalanise (talk) 13:41, 13 November 2010 (UTC)

Distance and travel time to Gliese 581

The page makes a simple error i think i am right in saying in the use of parsecs (20) over light years, a factor of 3.26x which makes a difference as to whether i can beam myself there in this lifetime without resorting to breaking the speed of light, so its relevance is actually quite large. Of course waiting to transfer from 581c to 581g probably takes 3 lifetimes so I suppose it can be forgiven. Mythole (talk) 15:02, 22 December 2010 (UTC)

The page gives the distance as "20.3 ± 0.3 ly", followed by "(6.2 ± 0.1 pc)", with ly linking to Light-year and pc linking to Parsec. Are you seeing something different? I have just checked the figures using [14] which gives a trigonometric parallax of 0.1578 (column note 7) arc seconds. This yields a distance in light years of 3.26 / 0.1578 = 20.659. The SIMBAD page has a similar parallax of 159.52 milliarcseconds or 0.15952 arcseconds. That yields 3.26 / 0.15952 = 20.436 light years. Each parallax has an error of about one percent, so 20.3 plus or minus 0.3 seems a reasonable fit with both these sources. -84user (talk) 16:09, 22 December 2010 (UTC)

GLIESE 581 g and f crossed out

Why are these crossed out? In the gliese 581 g article it also says this. The source listed is an opinion and only doubts the fact that they do not exist, there is no actual proof these planets do not exist. — Preceding unsigned comment added by 81.204.100.196 (talk) 15:48, 10 December 2011 (UTC)

There isn't really any proof they exist either. atomic7732 20:18, 10 December 2011 (UTC)

Star System ?

The article made several mentions of Gliese 581 being a "star system", however I find no mention of any stellar companions in its neighbourhood. I assume some may be confusing star system with planetary system a this lack of distinction which can be misleading. --EvenGreenerFish (talk) 04:59, 12 April 2012 (UTC)

Corrections need to be made to the corresponding planetary articles

The existence of Gliese 581 G and F have not yet been confirmed (In fact, they seem to be in the process of being disproved), yet the articles for the planetary companions of Gliese 581 are written as if their existence is without doubt. This needs to be fixed, and future edits that support this viewpoint without evidence need to be blocked.

VelociraptorBlade (talk) 23:53, 24 May 2012 (UTC)

g seems to be somewhat better supported by new data (see "misnamed" thread below), but you're right that f and g should not be considered to be confirmed in any WP article until there is scientific consensus on the issue. --Roentgenium111 (talk) 17:25, 26 July 2012 (UTC)

Here's the link to Vogt's new paper. He revises g's minimum mass downward to 2.2 Earth masses, but does not seem to defend f's existence himself. --Roentgenium111 (talk) 17:30, 26 July 2012 (UTC)

Debris Disk?

I came across this article from Zeta Tucanae, and it states that Gliese 581 has a debris disk… in 2009. Was this never noticed, or what? I'm not entirely sure how to translate the data into something meaningful (infrared excesses to semi-major axes, mainly), but this going apparently entirely unnoticed by wikipedia is a bit odd. Has this been invalidated at some point? ShellfaceTheStrange (talk) 17:33, 14 June 2012 (UTC)

Resolved! A debris disk around an old M-dwarf is a rarity-and-a-half. Gliese 581 continues to surprise! ShellfaceTheStrange (talk) 01:22, 22 November 2012 (UTC)

It's described in the two tables in this article as a "Comet belt" but is the composition of the Dust Disk so precisely known? Could it not possibly be instead a Debris Disk with a very low volatile content, like the one around Epsilon Eridani and Zeta2 Reticuli? — Preceding unsigned comment added by 81.157.226.225 (talk) 04:31, 4 December 2012 (UTC)

Gliese 581g officially confirmed

Gliese 581g officially confirmed.

News:

http://www.universetoday.com/96374/exoplanet-gliese-581g-makes-the-top-5/

http://phl.upr.edu/press-releases/fivepotentialhabitableexoplanetsnow

— Preceding unsigned comment added by 77.121.210.102 (talk) 09:23, 25 July 2012‎

No, it isn't. Note the quotation marks in your first reference. It seems to be supported better now, but is still controversial, as stated in your references. There is actually no authority that declares exoplanets to be official, BTW. (And please sign your posts.) --Roentgenium111 (talk) 17:22, 26 July 2012 (UTC)

Correct, as I said on the Gliese 581g talk page;

"Given that all the confirmation talk is coming from the "discovery" team then I would say the question is still up in the air. The paper claiming confirmation is actually a riposte to a paper by another team which showed no evidence of the planet. The planet won't really be confirmed until Vogt's peers accept his teams analysis or at least cannot robustly challenge them. Until then the planet is still not confirmed. As usual there are plenty of editors that have a complete lack of understanding of how science works and the ability to reason, which is why the Wikipedia articles at present are bastardised."

ChiZeroOne (talk) 21:28, 26 July 2012 (UTC)

You lied, ChiZeroOne, Gliese 581g has been already added in catalog, here's more information about Gliese 581g in catalog and data:

http://phl.upr.edu/projects/habitable-exoplanets-catalog

http://phl.upr.edu/projects/habitable-exoplanets-catalog/data

— Preceding unsigned comment added by 77.121.210.102 (talk) 16:18, 29 July 2012‎

77.121.210.102, please be civil, and re-read my first reply. Addition to that inofficial catalog does not at all mean confirmation. It only means that the catalog creators consider Vogt's new paper to give "significant evidence" for the planet's existence, nothing more. --Roentgenium111 (talk) 17:05, 29 July 2012 (UTC)

Well aren't you a nice fellow... This "PHL" has no official capacity whatsoever so I don't know why you are placing any emphasis on it, there is no such authority with regards to exoplanets. Indeed the article published on their website admits what is ultimately is their editorial decision isn't going to convince others;

“The controversy around Gliese 581g will continue and we decided to include it to our main catalog based on the new significant evidence presented, and until more is known about the architecture of this interesting stellar system” said Abel Méndez, Director of the PHL @ UPR Arecibo."

They aren't convinced either, citing only "more promising" evidence. ChiZeroOne (talk) 17:44, 29 July 2012 (UTC)

Here we go again... [15] 46.126.76.193 (talk) 20:57, 18 September 2012 (UTC)

And another one... [16] - planet d is back, f and g are still gone. 84.73.25.195 (talk) 21:27, 23 February 2013 (UTC)

After all, it now seems that neither Gliese 581f nor Gliese 581g exist:

V. V. Makarov, C. Berghea, and M. Efroimsky. 2012. "Dynamical Evolution and Spin-Orbit Resonances of Potentially Habitable Exoplanets: the Case of GJ581d." The Astrophysical Journal, 761:83 [17]

Why kill one HZ planet when you can kill ALL the HZ planets?

Three planets (b,c,e), the rest is just stellar activity. [18] 77.57.25.250 (talk) 22:04, 3 July 2014 (UTC)

This planet does not exist

http://www.sciencemag.org/content/early/2014/07/02/science.1253253 Time to update the page — Preceding unsigned comment added by 2601:A:4800:5E0:9167:112D:758D:9C9D (talk) 11:23, 6 July 2014 (UTC)

Yeah, the entire planetary system section needs a substantial rewrite. As it stands, the reader has to get past two outdated representations of the system to get to the current listing of basic mass/orbit properties. My inclination is to get rid of the first two orbitboxes and discuss candidates d, g and f in the text only, while retaining the activity-corrected orbital solution of Robertson (2014) and moving it somewhere near the start of the section. Overview first, then history. 77.57.25.250 (talk) 16:54, 7 July 2014 (UTC)

Merge proposal 05 Jul 2014

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.

The result of the discussion was merge all. 77.57.25.250 (talk) 07:46, 30 July 2014 (UTC)

---

I propose that the articles Gliese 581 d, Gliese 581 f and Gliese 581 g are merged into this article. While the case for having an article for these objects (particularly the habitable zone candidates) would be clear if they were thought to exist, it now seems that all three of these detections were actually the result of stellar activity. It therefore makes sense to discuss them as part of the history of planet claims in the Gliese 581 system, but having separate articles gives undue weight to the now-disputed planetary interpretation of these radial velocity signals. 77.57.25.250 (talk) 10:14, 5 July 2014 (UTC)

Discussion

• Support. Reasons: d, f, and g remain unconfirmed; GA status of target parent article; and post-merge article prose size remains within normal parameters, i.e. > 60 kB. Viriditas (talk) 11:53, 5 July 2014 (UTC)
• Support: The research said out of the 4 planets (e, b, c, d) and 1 unconfirmed planet (g), d and g did not exist. I'm not sure if it even mentioned f. --Article editor (talk) 02:48, 6 July 2014 (UTC)
  • Reply: The Robertson et al. 2014 paper mentions f in the intro as a historical note. Other authors had already demonstrated that the data supporting the discovery f was inadequate.
• Support FWIW, I (a researcher in the field) agree with this suggestion of merging the entries for d, f and g into the star's page. — Preceding unsigned comment added by 71.58.213.25 (talk) 16:59, 7 July 2014 (UTC)
• Partial If we're measuring credentials, about the only one I can claim is that I called shens on d back in 2012. (This was based on Baluev's analysis; it just happened that Baluev was right.) I prefer a separate article on the history of the controversy around these three planets. That history has now accumulated some sizable text. Also I like to avoid clutter on this system as a system. We can still have a smaller section on that here, as long as it links to the larger article for the overrun. -- Zimriel (talk) 03:17, 9 July 2014 (UTC)
  • That might be needed if we were dealing with a large prose size, but the potential prose size post-merge is quite small. Why not wait until after the proposed merge to create a summary style section and split the material out? Viriditas (talk) 03:59, 9 July 2014 (UTC)
  • I agree with Viriditas here, we don't need to render the history of the controversy as a blow-by-blow account of every paper on the issue. I think it makes sense to avoid clutter by using subheadings under the planetary system section (something along the lines of overview/confirmed planets/debris disc/detection history). 77.57.25.250 (talk) 16:59, 9 July 2014 (UTC)
• Partial - not my specialty, but I support partial merger : more centralizing so the system article is the main article so you get a better overall view and do not have messages from earth under 581d being better than here. Think should still have exoplanet specific article for that exoplanet-specific info though, and for better view under overall category exoplanets. Markbassett (talk) 04:47, 10 July 2014 (UTC)
  • What do you feel the value is to a reader of having an entire separate article dedicated to a planet that is not believed to exist? 77.57.25.250 (talk) 06:01, 10 July 2014 (UTC)

You mean like Vulcan...? ChiZeroOne (talk) 21:10, 10 July 2014 (UTC)

Which has a far longer history to it that led towards a fundamental revision to basic theories of physics, as opposed to the exoplanet claims which have been around for less than a decade and haven't really overturned anything. 77.57.25.250 (talk) 21:49, 10 July 2014 (UTC)

Length of time has no bearing on whether a subject is worthy of an article on Wikipedia. Vulcan did not lead to general relativity, the development of general relativity theory merely obviated the need for Vulcan to explain Mercury's orbit. In just the same way the more accurate modelling of G581's magnetic activity removes the need for G581 g etc to explain the signals in the RV plot. Whether a planet is used to explain the peculiarities of an orbit or peculiarities of an RV plot is neither here nor there. They are still both postulations since proven to be false. ChiZeroOne (talk) 22:31, 10 July 2014 (UTC)

Ok enough splitting hairs, do you have a point or are you just being pedantic for pedantry's sake? 77.57.25.250 (talk) 22:35, 10 July 2014 (UTC)

Splitting hairs? You were the one saying they were completely different! The point is obvious, clearly there are cases where things that were later shown to be false have an article devoted to them. ChiZeroOne (talk) 22:58, 10 July 2014 (UTC)

• Support, there are absolutely zero reasons to have articles for unconfirmed or (in this case) flat-out rejected exoplanets. Literally all they do is mislead readers. StringTheory11 (t • c) 23:24, 10 July 2014 (UTC)
• Support - merging Gliese 581 d, Gliese 581 f & Gliese 581 g articles with the Gliese 581 article makes sense - esp since the noted presummed exoplanets seem to be false detections and may not exist in fact - based on recent studies => http://www.sciencemag.org/content/early/2014/07/02/science.1253253 - Enjoy! :) Drbogdan (talk) 13:06, 16 July 2014 (UTC)
• Support weakly. I don't much mind one way or the other, and am poorly familiar with the subject, but the arguments for a merge seem reasonable. I assume that the deleted articles will be converted into redirects to the merged article? Then all that is necessary is to ensure that someone produces a coherent and comprehensible merged product. Good luck! JonRichfield (talk) 17:49, 17 July 2014 (UTC)
• Support - I do not see any strong argument to have separate article. And the size of the merged article would still be reasonable. --Silvio1973 (talk) 14:37, 25 July 2014 (UTC)
• Support - It would make it easier to the reader to understand the topic and highlight the fact that the three planets are unconfirmed. --Joujou007 (talk) — Preceding undated comment added 11:07, 29 July 2014 (UTC)

Progress

Given the above discussion pretty clearly leans towards support, I am proceeding with the merge in the following order. 77.57.25.250 (talk) 20:29, 29 July 2014 (UTC)

• Gliese 581 f - DONE
• Gliese 581 g - DONE
• Gliese 581 d - DONE

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Image requests

Couple of image requests:

• Orbit diagram for the 3-planet solution (similar to figure S6 in Robertson et al. 2014).
• Image of the debris disc - it is noted as resolved in Lestrade et al. (2012), so are there any images we can use here?

77.57.25.250 (talk) 21:15, 13 July 2014 (UTC)

"Gliese 581 d"

The usage of Gliese 581 d (edit | talk | history | protect | delete | links | watch | logs | views) is under discussion, see talk:Gliese 581 e -- 65.94.169.222 (talk) 07:22, 8 August 2014 (UTC)

Please see the paper: "Dynamical evolution and spin-orbit resonances of potentially habitable exoplanets. The case of GJ 581d." The Astrophysical Journal 761:83 (2012) ( http://iopscience.iop.org/0004-637X/761/2/83/ )

The analysis of data, presented in this work tells that Gliese 581 f and g do not exist, while d must be real. 71.178.188.237 (talk) 16:39, 27 November 2014 (UTC)

List of planets in this article and on nameexoworlds.org not identical

The planets in this GJ 581 system are on of those that will get a common names next year. But the website created for this very task (http://nameexoworlds.org/#planets) has some slightly different data! GJ 581 b,c on the website are pretty much identical to the data of those planets in the article (only some really minor differences in masses and orbital parameters exist). I thought that GJ 581 d on the website might be identical to our GJ 581 e here, and just has a different identifier because the previously "detected" planet d was a spuke. But actually the attributes don't fit. So either the article or nameexoworlds.org is wrong. --Sirius3100 (talk) 00:01, 8 October 2014 (UTC)

correction: The planets in this GJ 581 system are on of those that may get common names next year. --Sirius3100 (talk) 00:16, 8 October 2014 (UTC)

Gliese 581d real again?

It looks like it's at least arguable that Gliese 581d might be real after all: see

Robertson, P.; Mahadevan, S.; Endl, M.; Roy, A. (2014). "Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581". Science. 345 (6195): 440. doi:10.1126/science.1253253.

and then this rebuttal:

Anglada-Escude, G.; Tuomi, M. (2015). "Comment on "Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581"". Science. 347 (6226): 1080. doi:10.1126/science.1260796.

but also the response to that from the authors of the first-cited paper:

Robertson, P.; Mahadevan, S.; Endl, M.; Roy, A. (2015). "Response to Comment on "Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581"". Science. 347 (6226): 1080. doi:10.1126/science.1260974.

-- The Anome (talk) 17:00, 7 March 2015 (UTC)

I still don't think d exists, based on that last-word response you've just cited. My thought at the time (scroll up) was for a separate page for the controversy. I repeat this request - focused on d. It's sparked a lot of news, sometimes front-page news. --Zimriel (talk) 22:24, 8 March 2015 (UTC)

Proposal to 'De-merge' Gliese 581 d due to new evidence proving its existence.

The previously dubious exoplanet GJ 581 d is back, new studies how that the plant is likely to exist. Because of this I feel that it is approprte to demerge and redo the "Histroy of detections," due to this new evidence. No word on GJ 581 g's existence. Davidbuddy9 (talk) 02:04, 27 March 2015 (UTC)

If you can provide a peer-reviewed paper that states this, then by all means do it. However, astronomy news sources are notorious for being factually inaccurate way too often and giving undue prominence to exoplanets, so I wouldn't trust a news source with this. StringTheory11 (t • c) 03:35, 27 March 2015 (UTC)

And about you saying it is not trustable, it's exactly the opposite as even this article doesn't extrapolate into saying something else about planets f and g. Link to the paper, as it seems to me, having read, it is a technical comment: http://www.sciencemag.org/content/347/6226/1080.2.abstract — Preceding unsigned comment added by 81.84.174.249 (talk) 18:03, 27 May 2015 (UTC)

@81.84.174.249:, Well, I can't argue with a paper. However, I just read the paper, and it does not seem to definitively state that the planet does exist either, but rather seems to state that the planet may exist. I still don't believe that an unconfirmed candidate (aside from the extremely rare exception such as Alpha Centauri Bb) exoplanet deserves an article of its own, and believe that, until the planet is confirmed, such information is better suited for the Gliese 581 article. StringTheory11 (t • c) 17:03, 29 May 2015 (UTC)

Proposed merge with Gliese 581 e

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.

The result of this discussion was: No consensus. MartinZ (talk) 19:14, 30 March 2017 (UTC)

---

The article on Gliese 581 e is pretty small, and is unlikely to expand in the future, so it would be better to simply merge it. MartinZ02 (talk) 14:30, 27 December 2016 (UTC)

I've never understood the logic of merging articles that are slow to grow. What evidence do you have about what's likely to happen in the future? It's an inconvenience to both readers and editors to remove articles (especially based on such premonitions). The cost of doing so outweighs the benefits (are there any?). — Aldaron • T/C 19:10, 14 January 2017 (UTC)

@Aldaron: The article will probably not grow much because there is isn't much to write about the subject. By merging the article, we can have all the content in the same article, instead of having the it divided between several ones. —MartinZ02 (talk) 10:24, 15 January 2017 (UTC)

And what are the costs in doing this? —MartinZ02 (talk) 10:26, 15 January 2017 (UTC)

Keep. While there are some pretty pointless exoplanet stubs, this doesn't seem to be one of them. The parent star is a substantial article, even though much of it is discussing exoplanet discoveries, and the addition of half a dozen more articles would make for quite an essay. The biggest problem I see is fitting in all the planetboxes as well as a starbox. I'd be happy to see you try and judge it on the results, maybe better than I'm imagining. Lithopsian (talk) 19:59, 5 March 2017 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

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New paper on the system

The CARMENES search for exoplanets around M dwarfs. Revisiting the GJ 581 multi-planetary system with new Doppler measurements from CARMENES, HARPS, and HIRES

There are two main results from this paper. One is a determination of the system's inclination and thus the true masses of the planets, which are about 30% greater than the minimum masses. This is similar to what was done at Gliese 876. The other is a confirmation of previous studies finding that Gliese 581 has only three detectable planets, and planet d does not exist.

The existence of planet d has been previously discussed e.g. here. Studies of Gliese 581's radial velocity data since 2014 have consistently supported a 3-planet system with a stellar activity origin for planet d (indeed no orbital solution for planet d has been published in over a decade) - Robertson2014, Hatzes2016, Trifonov2018, Dodson-Robinson2022, and this new paper (Stauffenberg2024) - but this has been disputed by some papers that don't analyze the radial velocity data - this debate in 2015 (which is addressed in the new paper), and recently Cuntz2024 which got d added back into the planetbox.

The Cuntz2024 study argued that planet d may exist based on a new measurement of the stellar rotation period, which unlike the rotation period found by previous studies is not twice the period of planet d. Unfortunately Stauffenberg2024 doesn't address this revised rotation period, but this shouldn't seriously affect their conclusion since the stellar rotation period isn't the sole basis for the refutation of planet d; the radial velocity variation is still correlated to stellar activity signals. I think planet d can be removed from the planetbox, as reflects the astronomical consensus. SevenSpheres (talk) 14:37, 17 July 2024 (UTC)