Talk:Extrasolar planet

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To-do list for Extrasolar planet: edit · history · watch · refresh
  • Maybe another reference about history of gravitational microlensing method
  • Might like to modify the gravitational-lensing diagram slightly
  • Remove the references to private parts that have been added
  • Add something on HD 209458 b#Atmospheric water vapor
  • Add links perhaps with some discussion to similar articles The Fermi Paradox, The Rare Earth Hypothesis and The Many-body problem
  • A list of instruments/telescopes used to find exoplanets and an indication of how useful they have been and how many exoplanets they have found perhaps also their operational ranges
  • Think the article could have a better link to the planetary habitability article. Perhaps a synopsis of that article plus a see main article link.
  • Discussion of static magnetic fields e.g. Mercury in properties section
  • Atmospheric expansion of hot jupiters

Contents

[edit] GQ Lupi b, Van Briesbroek 8B

GQ Lupi b isn't an exoplanet but a brown dwarf. This one would fit better: [1] but I don't know how too include it

The problem for the 'planets' found by direct imaging is that for young substellar objects the mass-luminosity function is not known. There are different kinds of models for young planets, some say this is a planet, some say it is a brown dwarf.

What about Van Briesbroek 8B? Or is that a brown dwarf? Archola 14:11, 24 September 2005 (UTC)

[edit] Pulsar planets

Should PSR B1257+12's 3 light major planets [2] be included? - Jeandré, 2003-06-06t20:52z

[3] This op-ed piece in the introduction about pseudo-planets that Wolszczan discovered is very very opinionated. There is currently no definition for planet. So any sub-brown-dwarf accretion large enough to be thought of as a planet, that orbits a star, is a planet. The hooey about pulsar planets not being real planets is chauvinistic crap.

If you use the disk-instability model to make giant planets, according to some opinins, these aren't planets either, as a 'real' planet is formed by core accretion, and disk-instability only forms brown-dwarfs.

[4] The definition of what a planet is, is currently under debate. Apparently the criteria were determined on Sept. 14th and if / when the group develops a consensus on the proposal, it will go to the IAU executive committee for a vote. AZ Central News Article --Jeff 17:51, 28 September 2005 (UTC)

PSR B1257+12 D could be defined as a planet if the 2006 redefinition of planet... it's larger than Ceres. 132.205.93.195 03:26, 18 August 2006 (UTC)

[edit] Edits 2003/2004

Intro needs clarification: Are they considered a part of Solar System, if not, how close need they be? Because when I first saw the word, I though it's any planet not in the Solar System, like those from other constellations. --Menchi 23:28 12 Jul 2003 (UTC)

Info clarified on Jul 12, 2003 by Oliver Pereira. --Menchi 19:53, Aug 21, 2003 (UTC)

"several million extrasolar comets have also been detected. " I never heard of those. Detecting comets should be much harder than detecting planets. I am tempted to remove this sentence, unless it's backed by some reference source. At18 19:25, 21 Aug 2003 (UTC)

I did a bit of research, and found that many comets have been indirectly inferred. Of course they haven't directly detected - too faint. I'm changing the sentence wording to reflect this fact. At18 21:21, 21 Aug 2003 (UTC)

I removed the space telescope part of this sentence: "Planets orbiting main sequenece stars were not discovered until the 1990's, when new space telescopes good enough were constructed", and rewrote the surrounding paragraph. -Wikibob | Talk 16:46, 2004 Aug 7 (UTC)

[edit] Supporting Images

added picture...if anyone can find a better one, that might be a good idea. I'm sure there are better ones out there somewhere. --ScottyBoy900Q∞ 02:13, 08 Oct 2004 (UTC)

Does anyone know of a map showing what is known of our galactic disk and the position of the discovered extra solar planets on it? It would really help to give readers a feel for how widespread the planets are and the reach of our detection methods. It also would give a sense of 'place' to the galaxy. I beleive that the most remote detection is near the edge of the galactic core. --DannyStevens 12:34, 7 June 2006 (UTC)

A map might be a good thing to have. Unfortunately, there are several problems. First of all, of course, space is three-dimensional and hard to portray on a two-dimensional map. Secondly, it's hard to know just how many stars to show. The ones with planets tend to not be very prominent to the unaided eye, so we'd want at least a few "landmark" stars, but it's not clear which ones or how many. Thirdly, there's a problem with the distance scale. If the map just covered a hundred light-years or so, it would leave out many known planets. If it went out far enough to include all or almost all known planets (thousands of light years) then there would be a lot of nearby planets that the map would show as right on top of each other. I haven't even found a copyrighted map, much less a public-domain one, that successfully avoids all those problems. But I'll keep my eyes out. Kevin Nelson 04:53, 26 June 2006 (UTC)
There is no map available, only the types of stars planets are most comonly found. Heavier "metals" are required to form rocky planetesimals and population I stars are canditates and these are found within the disk of a galaxy. Hot O and B type stars do not live long enough to form mature planetary systems so stars similar to our Sun are the best canditates - F and G type stars (of course, planets have been detected around pulsars and brown dwarfs so there are always exceptions to the rule). NASA's PlanetQuest website is the best source of a map of planets.--Sofsoldier 05:00, 10 July 2006 (UTC)

All in all the images used with this article are pretty good, but IMHO there's room for improvement. For one thing, my preference would be to have fewer artist's conceptions---there's certainly room for that sort of thing, but they're quite speculative. So I think we shouldn't have too many in a strictly factual article. Secondly, I'm not too happy with the image that illustrates gravitational microlensing. The thing is that there are TWO stars involved: the source star and the planet's parent star. The diagram fails to make that clear. Finally, I would like a diagram illustrating the radial-velocity (Doppler) method. I may try to make one myself, but if anyone has a good image on-hand that would be a good thing to add. Kevin Nelson 22:44, 22 July 2006 (UTC)

[edit] Planet naming

I edited the planet naming conventions. Extrasolar planets are not named by orbit, but by discovery date. A great example is the Gliese876 system (as in the article). The clostest, smallest body is designated "d," not "b" or "c."--Sofsoldier 05:07, 10 July 2006 (UTC)

[edit] Non-working or Non-English Links

It's nice to see external links to searchable databases of extrasolar planets. This would allow various user-driven search/sort criteria like sort by ascending distance from earth, etc.

Unfortunately one link points to a German language site: | searchable dynamic database of extrasolar planets and their parent stars

And another link points to a non-functioning server: | Extrasolar Planet XML Database

I found this searchable database, but it doesn't allow sorting by distance from earth: [5]

I found this one, which allows sorting by all criteria; not sure if it's appropriate to reference or not: Joema 03:30, 18 December 2005 (UTC)

http://vo.obspm.fr/exoplanetes/encyclo/catalog-main.php?mdAff=output#tc

[edit] Extrasolar Moons

Does anyone know of any Extrasolar moons? Any information will be helpful on this subject as I have not yet heard of any "real case" of an extrasolar moon. Maurice45 17:55 23 January 2006 (UTC)

I personally know of none, and moreover, I think at this point it is extremely unlikely that one has been detected. This should not be taken as evidence that other planets don't have moons, however; it's still not possible to detect even a planet the size of the Earth in almost all cases, let alone something smaller. So the selection effects rule out any confirmation or refutation of moons around other planets at this point. Motorneuron 22:08, 8 March 2006 (UTC)motorneuron

If an "exomoon" had been detected I'm pretty sure I would have heard of it. NASA's Kepler satellite may find some, but I doubt any will be found before it goes into operation. Kevin Nelson 19:02, 21 June 2006 (UTC)

It is assumed a moon of a planet would be much less massive than its host. We have only been able to detect down to about 7.5 Earth-masses. It is hoped astrometry could detect an orbiting moon but this is highly unlikely. The Terrestrial Planet Finder and DARWIN - orbiting infrared interferometers set to launch in the near future - could possibly be sensitive enough to detect large moons, but we will have to wait for the initial results to see just how sensitive these instruments will be.--Sofsoldier 05:04, 10 July 2006 (UTC)

So could the masses of currently detected planets actually include exomoon mass? A planet that seems to be 7.5 Earth masses could have a .5 earth mass moon and itself be only 7 earth masses. How could that be detected? DannyStevens 13:42, 23 August 2006 (UTC)
In principle, it does seem possible that the currently cited mass could include the mass of a moon. But mass estimates for exoplanets typically have pretty substantial error ranges, and I would expect that the mass of any moons would normally be less than the error range. The transit method, if performed with sufficient precision, would enable the detection of moons and enable an indirect estimate of their masses. Kevin Nelson 03:28, 27 August 2006 (UTC)

I deduced the existence of a moon inside the Mira star R Hydra. Supposedly it has since being swallowed up by R Hydra evolved into a protostar or a star. I wrote about my analysis of R Hydra and this hypothesis in the chapter "Intrastars" in my book "Making sense of Astronomy & geology" (2000) as well as in a less sophisticated chapter in the earlier, less sophisticated edition "Astrophysical discoveries" (1999). Dirk Bontes 17:21, 5 October 2006 (UTC)

Without buying your book, can you provide any data that supports your hypothesis? Sofsoldier

Data? You mean an observational fact that preferably can be observed repeatedly? It is called a light curve and the light curve graph of R Hydra can be found in most books about Mira type variable stars. Dirk Bontes 05:04, 21 November 2006 (UTC)

[edit] New Records

Today's announcement of the 4x earth mass rocky planet has been added, but looks like it will need to be added to the table under the following categories: smallest, and furthest from earth. I'll leave that to the experts as I may be wrong. Jafafa Hots 02:01, 26 January 2006 (UTC)

I have now done that. Kevin Nelson 08:18, 22 June 2006 (UTC)

[edit] Zeta Reticuli

I find it interesting that no planets have been found around the binary star system of Zeta Reticuli. There was a planet found in 1996 and added to the Extrasolar planets catalog, but it was removed a few days later. What's the odds that this would happen to a star system so caught up in Ufology? Interesting! Barney Hill 23:35, 26 January 2006 (UTC)

[edit] Van de Kamp and Barnard's Star

Is it worthwhile to add some history about Peter van de Kamp and his claim about a planet orbiting Barnard's star? http://www.public.asu.edu/~sciref/exoplnt.htm

Definitely. The article's coverage on earlier studies is almost nonexistent.--Jyril 13:07, 9 May 2006 (UTC)
I've added a little, but the article is already flagged as potentially too long. So I don't think a whole lot should be added about this aspect of the subject's earlier history.Kevin Nelson 04:47, 26 June 2006 (UTC)
We could add a sub-article on the history of the search for exoplanets and then link it to this one, thus providing the information but not elongating this article too much. Vsst 22:50, 31 May 2007 (UTC)

[edit] Methods

It doesn't talk much about how the transit method actually works, and how it can reveal the size of a planet. How exactly does that work? karlchwe

Good question, I updated the article. When the planet crosses its host star's disk, the star dims a bit (a couple of percent at maximum for a Sun-like star). If you can determine the star's diameter, you can estimate the size of the planet.--Jyril 15:09, 6 May 2006 (UTC)

[edit] Erroneous detections in "History" section?

It seems sort of strange that the first section ("History of Detection") discusses the spurious detection of the HD 114762 "planet" without discussing various other previous spurious detections. It seems to me that either there should be a whole paragraph there about the (lengthy) history of spurious detections, or else the discussion of HD 114762 should be cut out completely. Alternately maybe the section could begin by discussing the brown dwarf/planet distinction, since HD114762 evidently is a brown dwarf, but I'm not sure that's a good thing to have at the beginning of the section. Kevin Nelson 01:55, 21 June 2006 (UTC)

[edit] Reorganization of sections

I would like to do a fairly substantial reorganization as follows. First of all, note that the "Methods of Detection" section starts out by mentioning six methods. One might suppose that then there is one subsection per method, but instead that section contains ten subsections...potentially highly confusing. So I'd like to merge several subsections there. Next, I'd like to add a brand-new section about statistical properties of exoplanets. One of the main underlying questions there is whether and to what extent our own Solar System is unusual. Kevin Nelson 06:00, 24 June 2006 (UTC)

[edit] Deleted subsection about eclipse-minima timing method

Somewhat reluctantly, I deleted the entire subsection. It's good material, but it's about a method that so far has not been used successfully, that has attracted at most moderate enthusiasm from astronomers, that would only be applicable in rather limited situations, and that would not provide data of a sort much different than other methods. So since length of the article is a concern, I deleted it to make room for other material that seems of more central importance. Kevin Nelson 10:37, 24 July 2006 (UTC)

I recovered this material and put it in the new Methods of detecting extrasolar planets article. --Cuddlyopedia 06:00, 5 October 2006 (UTC)

[edit] Mysterious problem with reference numbers

I don't know what's going on, but all of a sudden the reference numbers got scrambled. It's as if some of the [1] tags are "double-firing" and creating two entries in the reference list at the end of the article. Then the first entry doesn't point back to anything in the article. The reference list then winds up much longer than it should be. I tried to revert but the problem recurs even when reverting to a previous version where it had NOT shown up. I've been working on this for more than an hour without much progress. You can see the problem for example in the 10:02 30 August 2006 version. The very first reference (to Marcy, Butler and Fischer) should be note 1, but it's listed as note 37. Then it turns out that there IS a note 1, but note 1 and note 37 are duplicates. Kevin Nelson 12:36, 30 August 2006 (UTC)

See Template talk:Cite web#Confused by bug. -- Jeandré, 2006-08-30t18:45z

[edit] WP:0.5 and FAC Nomination

I have nominated this page for inclusion in Wikipedia:Version 0.5. The way I see it, this is a failed FAC solely due to inline citation problems, which seems to have been fixed quite nicely. I would recommend that this article be re-nominated as a Featured Article Candidate.

There's still one section (General Properties) that is completely unsourced. And from my perspective, that is possibly the most important section in the article. Once that is fixed, I think it will be time to re-nominate the article for a Featured Article. Kevin Nelson 00:18, 1 September 2006 (UTC)
I am now nominating this article as a FAC. The previous problems identified with it appear to have been entirely corrected and in addition a wide range of other improvements have been made to the article. Kevin Nelson 07:36, 7 September 2006 (UTC)

[edit] "Planetary system or star system"

In the opening sentence, it's not clear to me what information is conveyed by "planetary system or star system" that is not conveyed by just "planetary system". The latter phrasing is more concise and, it seems to me, less confusing. The former phrasing might imply to some readers that some planets are in star systems INSTEAD of planetary systems, which is surely not an implication we want to make. Kevin Nelson 04:32, 9 September 2006 (UTC)

Thanks for the comment - that was me. The preceding text is equally confusing; at least currently, the 'or' statement clarifies the point. By not noting 'star system' – i.e., "a planet ... that ... belongs to a planetary system beyond the solar system" – there's an implication that the solar system is just a planetary system. For clarity, a possible rephrase is: "beyond that of the solar system" or "belongs to a planetary system beyond the solar system's planetary system" or perhaps "beyond the solar system (and) in another star system". Thoughts? Cogito ergo sumo 04:52, 9 September 2006 (UTC)

All right, I see your point. It seems to me that the opening of this article should preferably not hinge on the meaning of "Solar System" or on possible misconceptions about it. So what do you think of the following opening: "An extrasolar planet, or exoplanet, is a planet that orbits a star other than the Sun, and that is therefore beyond the Solar System." Kevin Nelson 07:39, 10 September 2006 (UTC)

Hello. I agree with you about not having the introduction hinge on notions of Solar System; however, given the topic matter, I believe it is important to somehow note 'planetary system'. So, as alternatives to the above, how about this:
OR
or similar. I can even see this being built into the 2nd or 3rd paragraph. Thoughts? Thanks! Cogito ergo sumo 08:06, 10 September 2006 (UTC)

I went ahead and made an edit that I think addresses your concerns. If you think there's still room for improvement, you can tweak it as you wish and I will check back here if you want to discuss it further. Kevin Nelson 07:35, 12 September 2006 (UTC)

Generally, it looks fine. Thanks! :) Cogito ergo sumo 08:19, 12 September 2006 (UTC)

[edit] Reference

There is a good review: Sozzetti A. (2005). "Astrometric methods and instrumentation to identify and characterize extrasolar planets". PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC 117 (836): 1021-1048. 

[edit] "Today's featured article" request questions

I went to Today's featured article/requests to try to get this article into the que to be listed as a "Today's featured article" sometime but I have to admit that I am rather mystified by the process. There is supposed to be an "adapted lead section"...should I just copy and paste the lead of the article as it now exists into that page with appropriate HTML tags like the other article leads on that page have? If so, then the main article may change while that "adapted lead" stays the same. I have spent a while searching for some document giving guidelines on this but haven't found anything. Kevin Nelson 09:18, 14 September 2006 (UTC)

I have seen several instances where the adapted lead that appears on the main page is different from the (newer) one in the article. Aran|heru|nar 09:53, 7 December 2006 (UTC)

[edit] Eccentricity of Extrasolar planets

In the following article: http://www.science.psu.edu/alert/Luhman9-2006-2.htm, a potential explanation is given for the puzzling eccentricities observed. This is only my second contribution, I would prefer to leave it in more experienced hands.

Added. --Cuddlyopedia 11:00, 28 September 2006 (UTC)

[edit] "orbiting stars other than the Sun" deletion

According to its Wikipedia article, the Solar System is defined as "the Sun and the retinue of celestial objects gravitationally bound to it". Consequently, an extrasolar planet - if it is not part of the Solar System - must by definition orbit a star other than the Sun. So I am deleting this phrase as redundant. Ribonucleic 16:47, 27 September 2006 (UTC)

Well - depending on which side of the controversy you come down on - an extrasolar planet could be a free-floating object not orbiting a star at all! But, I agree, the phrase was redundant, especially given the second paragraph. --Cuddlyopedia 05:10, 28 September 2006 (UTC)

[edit] Move 'Methods of detection' to its own article?

The present article is already longer than generally desired, and is only likely to get longer as new discoveries are made. That normally means it's time to see if there are any parts that can be hived off into their own article. 'Methods of detection' seems tailor-made for that, as it is self-contained and prone to technical detail. We can then have a short section here that references the new article and just gives short summaries of the methods. I suggest 'Methods of detecting extrasolar planets' as a title for any such article. Any objections, comments? If no objections within the next week (or longer if people think it appropriate), I'll make the change. --Cuddlyopedia 05:10, 28 September 2006 (UTC)

Agreed, the article does appear to be too long. The removed methods of detection should also be restored. Sdp1978 18:49, 29 September 2006 (UTC)
As no objection (and some support), new article created with detailed information copied from here, and summary created in its place. --Cuddlyopedia 20:35, 4 October 2006 (UTC)
You forgot to update the references Sdp1978 22:53, 4 October 2006 (UTC)
I've initialised the references in the new article. (Thank you.) Or did you mean something else? I've also added the material on detection methods Kevin Nelson deleted here in July. --Cuddlyopedia 06:00, 5 October 2006 (UTC)
Good Work! --Sdp1978 14:35, 5 October 2006 (UTC)

[edit] Alternative interpretation of radial velocity and transit observations

In my book I have proposed a different interpretation of the periodicity in the spectral shift of these stars, as due not to the Doppler effect and radial velocity changes, but as due to the Zeeman effect.

("Making sense of astronomy & geology" (2000) as well as in a less sophisticated chapter in the earlier, less sophisticated edition "Astrophysical discoveries" (1999); chapter: "Eta Carinae, the illusion of exo-planets, and the Zeeman effect".)

The brightness of the star and these magnetic effects are causally related, hence the supposed transit by a planet of some of these Zeeman effect stars is an illusion as well. Dirk Bontes 17:36, 5 October 2006 (UTC)

The radial velocity hypothesis can be proven easily - and my Zeeman effect hypothesis disproven simultaneously - by supplying a photograph of the planetary disk of such an exoplanet. Nobody has made such a photograph and according to my Zeeman effect hypothesis nobody ever will. There is no conclusive evidence - no observation - that these radial velocity exoplanets in fact exist. Indeed, the "extremely odd" orbits of some of these alleged exoplanets indicate that they do not exist. Dirk Bontes 10:20, 20 November 2006 (UTC)

I would be curious to see any computer simulations you have done in regards to these orbits. Do you have any screen grabs of simulation results? Sofsoldier

Computer simulations? Ever hear of the phrase "Garbage in, garbage out"? Computer simulations do not prove anything. Please stop boring me with your computer simulation pseudoscience.

Unless our solar system is not a run of the mill solar system, all planets within the relative distance of the orbit of Venus - in our solar system the planet Mercury - just like Mercury must have an extremely excentric orbit that precesses fanatically as required by the general theory of relativity. The alleged "hot Jupiter exoplanets" orbiting as close to their star as to nearly touch them, all have perfectly circular orbits that are not visibly precessing. That contradicts what we know about the extremely excentric and rapidly precessing orbit of such a planet (Mercury). Ergo these exoplanets cannot and do not exist.

I challenge anyone to provide a photograph of the planetary disk separated from its parent star of one of these alleged exoplanets. That will be real science. It will never happen. Dirk Bontes 05:37, 21 November 2006 (UTC)

Why photographs? The resolution of most telescopes does not permit that yet. It's also unnecessary. There are much more refined ways to detect the presence of exoplanets and planetary disks than just by photographing visible light. Besides, since your "theory" is pretty much of the fringe variety, Wikipedia is in no way obligated to mention it. Motormind 20:28, 7 December 2006 (UTC)

So you think that photographic evidence is unnecessary, Motormind? That is also the position of the people who claim that the Moon is a large Swiss cheese with holes in it (presumably made by Moon mice). Science it is not. You say: "There are much more refined ways to detect the presence of exoplanets and planetary disks than just by photographing visible light". You are very vague. Like what much more refined ways? (Please, please do not bore me with fairy tales about interpretations of radial velocity and transit observations. Interpretations are not facts.) Show me a photograph. Show me solid evidence instead of pseudoscientific Swiss cheese. Dirk Bontes 02:31, 14 December 2006 (UTC)

[edit] Is extra solar planet a misnomer?

Under the new definition of a planet, is the term Exoplanet preferable above Extrasolar Planet? Hopquick 17:46, 13 October 2006 (UTC)

The new definition is only for Solar system planets. 'Extrasolar planet' and 'exoplanet' are synonymous, the first being more "formal".--JyriL talk 19:05, 13 October 2006 (UTC)
Just could'nt resist it: it's the IAU definition that is a linguistic and scientific misfit - just disregard it! An exoplanet is a planet that is not in our solar system, i.e. a extrasolar planet - perfect terms both, no doubts, not hard to identify them, no risk for misunderstandings. Regarding all confusions coming from the IAU planet definition - let's just wait and see if they're able to improve it from the level of ridicule. Rursus 22:00, 7 December 2006 (UTC)

[edit] Anymore articles?

Does anybody know where I can find more articles on astronomy? If you do email them to [address removed]. Thanks.75.44.152.183 03:48, 5 December 2006 (UTC)Holly Brown.

Wiki has also an Astronomy portal: http://en.wikipedia.org/wiki/Portal:Astronomy xeryus 00:35, 7 December 2006 (UTC)

[edit] Awesome article

This article is very awesome and interesting to read and I have it now on my watchlist<br?http://en.wikipedia.org/wiki/User:Berniethomas68 01:09, 7 December 2006 (UTC)

[edit] Wrong Picture

The first picture is displayed as George W. Bush and the caption does not match. 71.247.90.213 02:17, 7 December 2006 (UTC)

You are currently viewing a revision from hours ago. The problem has been fixed and should show up normally if you reload the page. Gdo01 02:19, 7 December 2006 (UTC)

[edit] LEAD tag

Please clean up the lead paragraph. FrummerThanThou 02:50, 7 December 2006 (UTC)

I don't see anything that goes against the Lead section guidelines. Titoxd(?!?) 03:10, 7 December 2006 (UTC)

[edit] Opening sentence

While I understand that the term 'Solar System' refers explicitly to our own star system (deriving its name from the Sun's Latin Sol), I fear that the average reader may associate the term 'solar system' with that of any star and corresponding orbit(s). Thus, I added "(i.e. orbits a star other than the Sun.)" to the end of the opening sentence to clarify that these planets are not simply planets without orbits, but with orbits around stars other than the Sun. I'm not sure this is the best grammatical way to do it, but I think such a clarification is needed. —Aiden 04:04, 7 December 2006 (UTC)

[edit] Since such objects do not satisfy the working definition of "planet" adopted by the International Astronomical Union

Any exoplanet do not satisfy the definition--Planemo 08:20, 7 December 2006 (UTC)

Yep, I was about to add that myself. That definition is only for planets that orbit our sun, so the reason for excluding those from this article doesn't make sense. as no extrasolar planets would fit that definition. VegaDark 08:25, 7 December 2006 (UTC)
There are two different definitions at issue. The recent redefinition that excluded Pluto, which is probably the one you are thinking of, does indeed apply only to the Solar System. As that was officially adopted, it no longer counts as a mere "working definition." But there is another working definition for exoplanets, as can be found in the external link under footnote 2. That latter definition is the one that excludes "free-floating" planets. This is certainly a confusing point, and the lead could probably do a better job of explaining it. In particular, I'm not too sure about the wikilink to the article about the first (Solar-System-only) planet redefinition. Kevin Nelson 22:11, 7 December 2006 (UTC)

[edit] Habitable zone

Hasn't the old concept that the habitable zone is small been under attack recently? I remember reading an article on new scientist but I'll be damned if I can find it right now --Energman 09:01, 7 December 2006 (UTC)

This question has been disputed for decades and though there seems to have been a bit of convergence of opinion to an intermediate value, the question is far from settled. The figures in the article actually show relatively large habitable zones, stretching most of the way from Earth to Mars and to Venus. Kevin Nelson 23:11, 7 December 2006 (UTC)

[edit] Cyrillic Text in First Paragraph?

What's up with the Cyrillic text in the first paragraph? Doesn't seem to fit an English-language wiki. Bob99 15:43, 7 December 2006 (UTC)

Someone reverted it as a good-faith edit made by an IP user. It shouldn't have been there, though. Nishkid64 15:44, 7 December 2006 (UTC)

[edit] Where did the article go?

The article is now blank. Is it just my computer, or has someone deleted every last word? —The preceding unsigned comment was added by 76.185.18.21 (talk) 23:41, 7 December 2006 (UTC). I've also noticed that if you try to edit, or look at the last update, everything is normal. What is going on?

  • Try to clear your browser cache and then refreshing the page. Sometimes the browsers insist of showing the cached (and inthis case, outdated) version - Skysmith 09:29, 8 December 2006 (UTC)

[edit] Penis Vandalism

It seems that there's a repeating jpg of a penis here. I can't seeem to get rid of it, since it's not showing up.

It's marked under 'see also'.

Any ideas? --64.233.226.150 18:00, 9 December 2006 (UTC)


Got it. Nice job, guys!

[edit] Notable Extrasolar Planets

I think it would be a good addition to add the closest Extrasolar planet to the earth which i believe is HD 189733b. I'd do it myself but I don't know the proper way to atribute sources in wikipedia.

What sources do you have? Tell us everything you know about it, and we'll add it in for you. enochlau (talk) 08:28, 10 December 2006 (UTC)

I read it at this press release: http://solarsystem.nasa.gov/news/display.cfm?News_ID=13897 Though I don't know if press releases count as valid source material or if it is still up to date. Also I have read that there are other suspected but unconfirmed planets that are closer.

I believe, it's Epsilon Eridani that should be added. It is confirmed and seems to be the closest discovered - 10.4 LY (BTW, compared to 63 LY of HD 189733b). See List of extrasolar planet extremes. Cmapm 03:25, 14 December 2006 (UTC)

[edit] Why was the history of detection section deleted?

Can't find any reason for this deletion. It seemed like a good section to me. —The preceding unsigned comment was added by Grant Gussie (talk • contribs) 21:41, 11 December 2006 (UTC).

It was vandalism, fixed now. Partly my fault for not realising what had happened (another anon removed the vandal text but didn't add back the missing section). —Quarl (talk) 2006-12-14 00:03Z


[edit] Status of 2M1207 b

The caption currently says that there is debate as to whether 2M1207 b is a planet or brown dwarf. I am unaware of any published argument that it is a brown dwarf, although Mohanty et. al. (preprint accepted by Astrophysical Journal) do estimate its mass at 8 M_J, which is close enough to the mass boundary for a bit of caution to be in order. If anyone has further information about a debate on the subject I would be interested to hear about it, but if I don't get any further information I will change the caption back to indicate that it is believed to be a planet. Kevin Nelson 11:01, 9 January 2007 (UTC)

[edit] Lack of discoveries

Why didn't we discovered any new planets for more than three months since October 9, 2006 (Columbus Day)? Will any new planets will be discovered this month? Cosmium 19:52, 13 January 2007 (UTC)

Well, the announcements of discovery usually come with confirmation, so probably many candidates have been found, but reporting false alarms isn't particularly useful, is it? They'll come.--Planetary 01:00, 30 January 2007 (UTC)
Perhaps we found all of them already :P enochlau (talk) 01:03, 30 January 2007 (UTC)
Likely never.--Planetary 01:07, 30 January 2007 (UTC)

I found that four new planets were finally discovered already in February, in which planets haven't been discovered for nearly four months. I am happy about that! Cosmium 17:57, 24 February 2007 (UTC)

[edit] HD 188753 A

A preprint by Eggenberger, Udry et. al. is now out in which they emphatically assert that they can find no evidence of the alleged planet around this star. The paragraph about this alleged planet has already been removed from the article, but I think it would be a good idea to rewrite it and put it back in as a disputed planet. First of all, I'm not sure that the existence or non-existence of the planet is entirely settled; Konacki may come back with a rejoinder. Secondly, this alleged planet attracted quite a bit of notice when it was first announced, so I think it would be a good idea to still have something about it. Kevin Nelson 10:14, 22 February 2007 (UTC)

I disagree. This planet is not listed in catalogs like the peer-reviewed Catalog of Exoplanets or the Encyclopedia of Extrasolar Planets, it existence would make no sense under our current understanding of planet formation, its separate page is still up for the interested, and this is already a long article. Enfolder 15:34, 22 February 2007 (UTC)

Encyclopaedia of Extrasolar Planets does indeed still list the alleged HD 188753 A planet, albeit under "Unconfirmed, controversial or retracted planets." It also has a link to a reply by Konacki in which he defends his work. So this is not a retracted planet. In my personal opinion, Eggenberger et al are very probably right and the planet is nonexistent. But as recognized experts continue to disagree I think it is reasonable for the article to continue to have a paragraph about this in which the dispute is discussed. Kevin Nelson 10:54, 23 February 2007 (UTC)

[edit] age for PSR B1620-26c

Minor point. The caption of the "artist's impression" of PSR B1620-26c states that the planet is "over 12.5 billion years old," while the text just to the left says that the planet is "13 billion years old." The article on the planet gives a figure of 12.7 billion years. Of course there is going to be some uncertainty in the age, but it would be less confusing if a consistent value is chosen for the text. Perhaps the 12.7 billion from the article? Is anyone familiar with the best guess for the age? Wesino 15:11, 11 April 2007 (UTC)

[edit] HD 209458 b - Atmospheric water vapor

The latest news on HD 209458 b, namely HD 209458 b#Atmospheric water vapor should be added to this article. Carcharoth 13:07, 12 April 2007 (UTC)

Agreed. There is a to do list where you can place your suggestions. Perhaps it would go on a section on atmosphere spectra in general. Sdp1978 13:19, 12 April 2007 (UTC)

Thanks. Noted on the to-do list. Carcharoth 14:50, 12 April 2007 (UTC)
Think that could go in the final paragraph of the general properties section. Which of course could be updated. Sdp1978 15:09, 13 April 2007 (UTC)

[edit] Link to HARP

The link to HARP in the new item about Gliese 581c doesn't appear to provide any info about this technique, so unless I am mistaken the link ahould be deleted. Robin Scagell 07:18, 25 April 2007 (UTC)

  • Additional link added to sentence leading to subsection of exoplanet detection methods. Abyssoft 15:27, 25 April 2007 (UTC)

[edit] SIM PlanetQuest

Hello everybody. I have undertaken the expansion of Space Interferometry Mission (see diff) dating back to November 2006. It is currently undergoing a peer review as well, I have left additional comments on the talk page.

I am wondering what this article is missing or where it needs work. I have completed two copy edits myself but fear that I may no longer be able to do much in that area. Any comments would be appreciated. IvoShandor 18:19, 27 April 2007 (UTC)

You could work through the to-do list at the top of the page.--Sdp1978 09:59, 28 April 2007 (UTC)
Eh? Anything there besides a recent peer review I put just FYI. I was looking more for commentary from unaffiliated readers. IvoShandor 11:32, 28 April 2007 (UTC)

[edit] Extrasolar planets in our galaxy

I estimate that 1080 billion extrasolar planets orbit 240 billion stars. BlueEarth 18:57, 5 May 2007 (UTC)

That's great. Zazaban 23:05, 6 June 2007 (UTC)

[edit] Notable(?) exoplantes

IMVHO, some of entries in "Notable extrasolar planets" chapter are not so notable. Expecially Corot-exo-1b is just another hot jupiter. In light of recent discoveries, some of previous entries must be dropped, for example Gliese 876 d (who cares about second lightest known exoplanet? Should be replaced with new, actualised entry in category "lighest known exoplanet"). In other words, list of notable exoplanet must be not only filled with new entires, but also revised as whole. --83.144.95.66 14:12, 26 May 2007 (UTC)

Do we even need all that information? Zazaban 23:02, 6 June 2007 (UTC)

I basically agree. I think that section is now just too long. The space would be better used for more general information. I would like to keep Gliese 876d however. The planets at the low end of the mass range are all especially interesting because they are getting down into the Earthlike range. Also, I would like to suggest that this section be arranged in terms of planets rather than years. Right now, we can have several different paragraphs for the same planet scattered around the section, and that just doesn't strike me as a very good way of organizing it. Kevin Nelson 12:18, 19 July 2007 (UTC)

[edit] Gliese 581c

The article currently argues that it has been "shown" that this planet lies outside the habitable zone. However, that's been done on the basis of an as-yet unpublished preprint, which has not yet been subject to peer review (though the preprint is the work of widely published researchers in the area, by the looks). Should the claim to be outside the habitable zone be toned down somewhat, say to "some researchers believe that..." for now? --Robert Merkel 02:59, 7 June 2007 (UTC)

[edit] HD 154345b

I have removed the description of this planet from the "notable" section of the article, because it was completely unsupported by the citation, and inaccurate to wit. This object has been mentioned once just in the literature -- in Wright et al. 2007 -- which showed that the orbit is so far unconstrained.

[edit] Image

It's somewhat confusing to have Image:Phot-14a-05-preview.jpg twice in the article, I'd say... can we fix this? --Ouro (blah blah) 06:26, 11 July 2007 (UTC)

[edit] Formula for radius and temperature

Here's the formula for calculating radius and temperature for extrasolar planets. You should add calculated r & T to extrasolar planet articles.

R_{planet} = \sqrt{\frac {\sqrt [3]{M_{planet}} \times \sqrt {R_{star}}} {\sqrt [4]{a}}}

T_{planet} = \frac {\sqrt [4]{L_{star}} \times 256} {\sqrt{a}}

where:
Mplanet is the mass of the planet
Rplanet is the radius of the planet
Tplanet is the temperature of the planet
a is the semimajor axis
Rstar is the radius of the star
Lstar is the luminosity of the star

Note: After finding the radius, you should find density by formula m/r³ and gravity by formula m/r². The radius of planets can only be calculated orbiting the main-sequence stars. Giants and subgiants have grew larger in radius and does not grow planets in radius because of the expanding star's radius.

--BlueEarth 18:05, 24 July 2007 (UTC)

Where did you get those from?!? I fail to grasp how the radius of a planet can be dependent on the radius of its parent star or of its semimajor axis. (Not to mention that density also needs to be factored in.) The formula for the temperature of the planet looks more reasonable. However, it has no units, and the use of semimajor axis instead of (weighted) mean distance to the star is highly suspect. Ben Hocking (talk|contribs) 18:20, 24 July 2007 (UTC)
I tried different set of radius formula for trying to find radius of the planet Gliese 581 c until I'll get exactly 1.5 RE as it was referenced. I made the temperature formula by trying to calculating the temperature of extrasolar planets with changing formula until I'll get exact value and accepting the formula from calculating effective temperature of Mars and Jupiter. BlueEarth 19:54, 24 July 2007 (UTC)
A general formula for the radius would be:R_{planet} = \sqrt [3]{\frac{3M_{planet}}{4 \pi \rho_{planet}}} where ρplanet is the density of the planet. If your units are cgs, ρplanet might not differ significantly from 1 (the density of water in g/cm3). There will be no simple way to deduce the density (except for using the radius and mass) as some planets are rocky, gaseous, etc. The temperature of the planet is also a little more complicated than what you have there. (I'll have to look into that one, as I don't have it off the top of my head.) Ben Hocking (talk|contribs) 22:07, 24 July 2007 (UTC)
A planet's density is not only affected by the material it is made of, but also by gravitational pressure which is significant for giant planets (gas giants like Jupiter, brown dwarfs and low-mass red dwarfs are all about the same size despite their highly different masses).— JyriL talk 22:52, 1 August 2007 (UTC)

This radius formula is nonsense. First off, the author claims it is based on the properties of a planet for which the radius isn't actually known, secondly it is not dimensionally consistent, thirdly it doesn't actually work for our solar system, so expecting it to work for every other planetary system is ridiculous. Look, if the radius and temperature of an extrasolar planet are unknown, just don't put them in the infobox. This is an encyclopaedia, it is a summary of what is known. If something isn't known, then we shouldn't pretend it is. Chaos syndrome 21:32, 29 July 2007 (UTC)

Theoretical surface temperature of a planet is

T = T_\star \sqrt[4] { \frac {1 - A} { 2 } } \sqrt { \frac {R_\star} {r} }

and for a rapidly rotating planet (when the amount of emitted radiation is equal across the whole surface)

T = T_\star \sqrt[4] { \frac {1 - A} { 4 } } \sqrt { \frac {R_\star} {r} }

A is the planet's Bond albedo, which obviously is unknown for extrasolar planets, and r is its orbital distance. R_\star is the star's radius. When we take atmosphere into account, things like greenhouse effect and heat currents guarantee the values given by the equations become wildly off-mark. For example, based on these Venus would be slightly cooler than Earth because of its very high albedo. — JyriL talk 22:52, 1 August 2007 (UTC)

[edit] Inclination and true mass

How can I calculate true mass when inclination is known? BlueEarth 16:54, 26 July 2007 (UTC)

The formula is

M = \frac {M_{min}}{sin(i)}

where Mmin is the minimum mass derived from RV measurements and i is the inclination in degrees. Note that we don't need this formula since the only cases when inclination is known (transiting planets) the true mass is already given. — JyriL talk 22:19, 1 August 2007 (UTC)

[edit] Notable extrasolar planets.

Should this section be split off into it's own article? Zazaban 22:32, 28 July 2007 (UTC)

It's definitely arguable - i.e., I have mixed feelings about it. Also, it needs some work - there's a lot of bad sentence structure, etc. I'll probably come back to it soon. Ben Hocking (talk|contribs) 23:41, 28 July 2007 (UTC)
Agreed, some of the planets should not even be there. Zazaban 21:45, 30 July 2007 (UTC)

I'll say leave it in extrasolar planet article as section. BlueEarth 19:20, 29 July 2007 (UTC)

I'd suggest to have its own article, especially as the list is bound to grow when they find water, a moon etc. In this article, reduce it to something much smaller. E.g.
The first verified exoplanet was PSR B1257+12, which orbited a pulsar. 51 Pegasi b was the first found orbiting a normal star and the first Hot Jupiter. HD 209458 b was the first planet seen transiting its parent star, confirming that the radial velocity measurements was finding real planets and not stellar oddities.
And so on for everything of note. The original text would all be at the new article. --GwydionM 18:11, 7 August 2007 (UTC)
That section deserves serious pruning. Most of the "notable" extrasolar planets don't really deserve a mention. The overhyped HAT-P-1b isn't as big as originally thought and TrES-4 is larger than it anyway. There's nothing special in TrES-1 and Corot-exo-1b. HAT-P-2b is less massive than XO-3b. There are doubts about the existence of HD 188753 Ab. SWEEPS-10 remains unconfirmed. There is no reason to include HD 28185 b and HD 70642 b. HD 28185 b orbits further than Earth a star that is less bright than the Sun and HD 70642 b... well, any planet that can have large icy satellites can fulfill that requirement. Why it and not 47 UMa b for example? — JyriL talk 09:41, 26 August 2007 (UTC)

[edit] Catalog of Nearby Exoplanets

This website is the best exoplanet listing websites. It has most frequently changed parameters for planets, and hence most recently. It is best to use this site to update parameters in extrasolar planet articles and list of confirmed extrasolar planets with the exception of Mu Arae, 55 Cancri, 47 Ursae Majoris, and 14 Herculis planets, which is cited from the Extrasolar Planets Encyclopaedia. BlueEarth 21:34, 3 September 2007 (UTC)

[edit] Semi-amplitude

How can I calculate semi-amplitudes for extrasolar planets using planet mass, planet-star separation, and star mass? I knew that semi-amplitude is how fast the star wobbles, usually in meters per second (m/s). The more massive the planet is, the faster the star wobbles, hence the higher the semi-amplitude is. The greater planet-star separation or more massive the star is, the slower the semi-amplitude is.

Is this right: K = 30.87 \times {\sqrt[1.5]{M_{planet}} \div \sqrt[2.5]{a} \over \sqrt{M_{star}}} Note: 30.87 is the semi-amplitude of one Jupiter-mass planet that orbits at one astronomical unit around one solar-mass star.

--BlueEarth 00:32, 9 September 2007 (UTC)

[edit] Tabular firsts

I've merged the following table into the article, from List of planetary extremes, (these aren't extreme...) 132.205.44.5 23:10, 12 September 2007 (UTC)

===Discovery firsts===

Title Planet Star Year Notes
First planet discovered PSR B1257+12 B, C PSR B1257+12 1992 first extrasolar planets discovered
Note 1: The planet around Gamma Cephei was already suspected in 1988.
Note 2: HD 114762 b was discovered in 1989, but was not confirmed as a planet before 1996.
First discovery by system type
First planet around a solitary star PSR B1257+12 B, C PSR B1257+12 1992 first extrasolar planets discovered
Note 1: HD 114762 b was discovered in 1989, but was not confirmed as a planet before 1996.
First free-floating planet discovered S Ori 70 n/a 2004 has mass of 3 MJupiter, needs confirmation
Note: Free-floating objects are not usually considered planets.
First planet in a multiple star system discovered 55 Cancri b 55 Cancri 1996 55 Cnc has distant red dwarf companion
Note 1: The planet around Gamma Cephei was already suspected in 1988.
Note 2: Gamma Cephei is the first relatively close binary with a planet.
First planet orbiting multiple stars discovered PSR B1620-26c PSR B1620-26 1993 orbits pulsar - white dwarf pair
First multiple planet system discovered PSR 1257+12 A, B, C PSR 1257+12 1992 a pulsar planetary system
First planet in star cluster PSR B1620-26c PSR B1620-26 1993 located in Globular Cluster M4
First discovery by a method
First planet discovered using the pulsar timing method PSR B1257+12 B, C PSR B1257+12 1992
First planet discovered by radial velocity method 51 Pegasi b 51 Pegasi 1995
First planet discovered by transit method OGLE-TR-56 b OGLE-TR-56 2002
First planet found by gravitational lensing method OGLE-2003-BLG-235Lb OGLE-2003-BLG-235L/MOA-2003-BLG-53L 2004
First discovery by star type
First pulsar planet discovered PSR B1257+12 B, C PSR B1257+12 1992
First known planet orbiting a Sun-like star 51 Pegasi b 51 Pegasi 1995
First known planet orbiting a red dwarf Gliese 876 b Gliese 876 1998
First known planet orbiting a giant star Iota Draconis b Iota Draconis 2002
First known planet orbiting a white dwarf (confirmed 2003) PSR B1620-26c PSR B1620-26 1993
First known planet orbiting a brown dwarf 2M1207b 2M1207 2004
first directly imaged planet
First free-floating planet discovered S Ori 70 n/a 2004 has mass of 3 MJupiter, needs confirmation
Note: Free-floating objects are not usually considered planets.
Firsts by planet type
first cool, possibly rocky/icy planet around main-sequence star OGLE-2005-BLG-390Lb OGLE-2005-BLG-390L 2006
Other firsts
First transiting planet HD 209458 b HD 209458 1999
Note: OGLE-TR-56 b is the first planet found by transit method.
First directly imaged planet 2M1207b 2M1207 2004

[edit] The planet count as per reference 1

The total count of confirmed exoplanets has been edited a lot recently following the reference at http://exoplanet.eu/catalog.php. Generally we've been matching the count at this reference, reverting misinformed or spurious edits and updating in line with updates to the source. Recent edits have taken a new line on this- totalling only confirmed exoplanets with a mass < 13 MJ and referencing the same source with a caveat comment next to it.

My issues with this are: firstly, that the inclusion criteria at the source already consider a certain margin of error regarding mass. Further, objects above 13 MJ are included only if they are orbiting a star with another companion of lesser mass (and are therefore likely to have accerated from similar material). The 13 MJ upper limit on planets is not an absolute since, by my admittedly limited understanding, mass alone is not sufficient for the object to be considered a fusor. Finally, the figure will be far harder to keep updated if rather than simply matching the figure at a curated list, we will need to go through the list to check masses before incrementing the numbers. Right now I'm happy to leave it to people who know better, but thought it might be useful to discuss this. DoktorDec 11:41, 15 September 2007 (UTC)

Thoughts?

According to planetary mass type, 13 MJ is the upper limit for planetary-mass object. That's why I exclude these objects with more than 13 MJ. In my own Microsoft Word documents, I exclude these objects. Objects with over 13 MJ don't consider planets, they are considered brown dwarf. BlueEarth 18:36, 15 September 2007 (UTC)

[edit] There is no proven "extrasolar planet"

This page should reflect the fact that there is no proven extrasolar planet. If one views a planet as a naturally evolved, i.e. condensed from a star forming nebula, object, there is zero evidence that can be used to assert that these objects are indeed *planets*. The surveys that use light frequency shifts can assert a "mass" of an object -- however they cannot assert it is a planet because they did not observe its formation. It could just as equally be a "borg cube" Jupiter Brain, whatever... And so to be completely accurate it should be labeled a "putative planet". Similarly observations based on occultation can only lay claim to the diameter of an object (or coorbiting objects). They have no concrete proof of a "planet". The assumption of extrasolar planets rests upon the assumption that the rest of our galaxy reflects our small solar system and it must be completely dead (other than the Earth). This is an anthropocentric perspective which should not be accepted in an Encyclopedia. Because we exist, it is clear that evolution to higher states of being is not impossible. The documentation by Lineweaver's group that most of the Earth's in our galaxy are older than we are points out the need to consider than extrasolar "planets" may not be natural but may instead be engineered constructs. If you cannot *prove* it is a planet you should not be writing about it as a given assumption.

"Putative extrasolar planets" is reasonable. "Extrasolar planets" is not.

Robert 11:08, 6 November 2007 (UTC)

This makes sense. But the sources call them planets, so we call them planets. I agree with you, but we follow the sources. Zazaban 03:37, 10 November 2007 (UTC)

[edit] There are no exoplanets!

Because they may at most be Extra Solar Planetary Mass Objects! A planet must orbit around Sun, thus there is nothing such as Extra Solar ones. I propose, in the spirit of astronomer culture that we invent an abbreviation instead of this "planemo" monstrosity, namely ESPMO, which matches SSSB very well, and then we name our eyes humanoid vision sensors HSV, looking through our tubular light enhancement devices TLED at the virtual surface of heaven VSH, making observation aided conclusions OAC:s, ... Said: Rursus ☻ 10:24, 10 November 2007 (UTC)

I personally find the idea that planets can only orbit the sun to be idiotic and unbelievably self-centred. Astronomers do call them planets, so I don't think this will make it into the article. Zazaban 19:45, 10 November 2007 (UTC)

Well, while I personally think that the definition of planet should be: 1.

   * is in orbit around a star,
   * has sufficient mass so that it assumes a hydrostatic equilibrium (nearly round) shape, and
   * has "cleared the neighborhood" around its orbit.

It is unfortunately

   * is in orbit around the Sun,
   * has sufficient mass so that it assumes a hydrostatic equilibrium (nearly round) shape, and
   * has "cleared the neighborhood" around its orbit.

which means technically, at the moment, there are no planets outside the solar system. The definition of an exoplanet is: 1. An object at least the minimum size of what something in the solar system has to be to be considered a planet and that is not big enough to fuse deuterium However, they are not planets outside the solar system but instead a different class of objects all together. So there are exoplanets, but exoplanets aren't planets outside the solar system but a different classification. Well, according to this: http://www.dtm.ciw.edu/boss/definition.html 68.175.106.168 20:33, 14 November 2007 (UTC)

I would suppose an extra paragraph about the definition of the word planet concerning extrasolar planets. The IAU is an extraordinary example for discrepancy concerning word definitions! Here is the IAU definition for planets which is, as said above, in orbit around "the Sun". There is, however, no definition of "the Sun". It could as well mean "its own sun" as well as "our sun" also called SOL in astronomy, but not in the planet definition (which makes it scientificly simply unknown which definition is ment). But that's not the only problem! Another FAQ page of the official IAU website clearly shows that the IAU isn't even sure about these definitions by itself. So for example, this FAQ page of the official IAU website is titled "Planets around other stars" where they shouldn't be called planets at all according to their own definition of the word "planet" if they are orbiting another sun (if SOL is realy ment with the words "the Sun" in the planet definition). On the other hand, the phrase "Extrasolar Planet" could well be an extra definition as is the phrase "dwarf planet" and could as such not-yet officially defined phrase be used for planetary objects around other suns! But, as it should be assumed that SOL is ment with the words "the Sun" in the planet definition, the word "planet" should probably not be used by itself for planetary objects around other suns. This may seem strange, but as this is an official encyclopedia it should stick to the official definitions, even if many of us and the astronomers think it is "stupid". If the most astronomers at the next IAU meeting will not leave the meeting early (as it was at the last meeting when the planet definition resolution was passed), they may be able to correct their mistake, if they think it is one. But since the phrases "Extrasolar planet" and "planetary object" are not yet officially defined by the IAU, they still can be used for planetary objects around other stars! So it could not be said, there are no "Extrasolar planets" since the IAU has proofen with its own "dwarf planet" definition that there can be used phrases with the word "planet" in it, without meaning "planets" by the definition of the IAU. Still, there should be an extra paragraph about this highly complex subject! People should know that these objects around other stars are not "planets" by official definition of the IAU, but still can be called "Extrasolar Planets". Greetings, ColdCase 22:34, 14 November 2007 (UTC)

[edit] HD/Henry Draper Catalogue

This BBC article mentions conventions of planet-naming -> . I wondered whether someone could confirm that the 'HD' in many exoplanets names is derived from 'Henry Draper Catalogue'. maxrspct ping me 19:33, 13 January 2008 (UTC)

[edit] Types of extrasolar planets

Shouldn't there be a list of the various types of informal classification used to group extrasolar planets, such as hot Jupiter, super-Earth or hot Neptune? Serendipodous 20:51, 29 January 2008 (UTC)

Yes, it should. I'll might add informal groups of extrasolar planets any time soon. BlueEarth (talk) 00:13, 30 January 2008 (UTC)

[edit] Another milestone ?

[6] The organic molecule methane has been detected in the atmosphere of a planet orbiting a distant star. The latest rumours say it concerns the gas giant HD 189733b, 63 light-years away, in the constellation Vulpecula.The discovery was made with Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS).Although the planet is too hot to support life as we know it, the finding demonstrates the ability to detect organic molecules spectroscopically around Earth-like planets in habitable zones around stars.NASA will hold a media teleconference at 18:00 GMT on Wednesday, 19 March, to report this unique discovery.

[edit] Any New High Quality Pictures of Exoplanets taken Yet?

Hey guys good to see a good discussion thread here. Does anybody know if there are any HQ pictures of exoplanets taken slightly close? You know where you can see what they look like? —Preceding unsigned comment added by Blueknightex (talk • contribs) 12:13, 8 May 2008 (UTC)

Once its gets fully published I think it could be listed in notable list.--Molobo (talk) 00:14, 16 March 2008 (UTC)

Thank You very much Blueknightex (talk) 12:17, 8 May 2008 (UTC)

[edit] Another one: Planet is 3x Earth's size

See Planet 3x Earth's size found around Brown Dwarf Star. Can this one be added? 65.173.105.197 (talk) 22:02, 3 June 2008 (UTC)

It was added to the database at reference 1 (http://exoplanet.eu/) on the 2nd of June. Added to this article on the same day. DoktorDec (talk) 19:01, 4 June 2008 (UTC)