Talk:Exoplanet

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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)

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)

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)

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)

Planet naming

• see Wikipedia_talk:WikiProject_Astronomical_objects#Extrasolar_Planets; there needs to be a default convention on naming the articles. 132.205.15.43 05:13, 25 Mar 2005 (UTC)

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)

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

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)

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)

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)

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)

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)

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)

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)

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)

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 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

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)

"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:

• An extrasolar planet, or exoplanet, is a planet (a constituent of a planetary system) that orbits a star other than the Sun, and that is therefore beyond the Solar System.

OR

• An extrasolar planet, or exoplanet, is a planet that orbits a star other than the Sun, and that is therefore beyond the Solar System. A constituent of a star system's planetary system, over 200 extrasolar planets have been discovered as of September 2006...

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)

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.

"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)

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)

"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)

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)

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)

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)