Talk:List of multiplanetary systems

General

On doubt

Doubtful planets?

Should doubtful planets be on this page at all? Perhaps they should go in hypothetical planet instead. 132.205.15.43 05:06, 30 Nov 2004 (UTC)

Solar system planets on hypotethicals page are mostly just hypothetical; on the other hand these doubtful planets have been false detections. Maybe they should have a list of their own as List of unconfirmed extrasolar planets (after all, this is a list of confirmed extrasolar planets). Jyril 15:45, Nov 30, 2004 (UTC)

I've moved the list to hypothetical planet, since they are definitely not confirmed planets, and appear to be on the way to being disproven planets. Hypothetical planet article allows for unconfirmed and disproven planets, according to what it says. 132.205.45.155 01:11, 1 Dec 2004 (UTC)

"Confirmed?"

In what sense are these exoplanets "confirmed?". For instance, HD 187085 b was detected by one group, but no other group has independently confirmed it. On the other hand, the group that made the detection has an excellent track record, being without a single mistake in over 100 planet claims. So perhaps the word "confirmed" is not the right one? Maybe "likely"? "Solid"? "Strong"? There is a peer-reviewed Catalog, a Table, and an Encyclopedia of exoplanets all maintained by professional astronomers, perhaps they could be used as a referee? Enfolder 05:43, 23 February 2007 (UTC)

Most of these planets are hot Jupiters which only take a few weeks of observation, max, to confirm yet another swing around the star. For them, the "confirmation" part isn't whether there's an orbital body. (Everyone knows there is.) The question is whether the body is small enough not to be a brown dwarf. No-one knows HD 187085 b's inclination, and so it is not confirmed to be a planet. (By contrast with, say, tau Boötis Ab, but that's another rant...)

That out of the way, your example is also a long-period orbit - say, on the order of three Earth years or more. There's certainly a problem there too. Anything published with a period of x years, if the only publication is from just one independent team 2x years from the start of the vigil, perhaps ought to be "non confirmed" even as an orbital body.--Zimriel (talk) 19:51, 12 August 2008 (UTC)

Comparison to Earth

I think most of the readers will want to compare the mass of the planets with Earth's mass, not Jupiters. The semimajor axis is already compared to Earth's, because of the unit used. Even if comparing the mass to Earth's mass means bigger numbers I think it is much more useful. Or at least we should have both columns. As an alternative, I wanted to add -for comparison purposes- Earth to the list, but it was removed. I still think it would have been useful. The current information is hard to handle if one has to consult a separate page with Earth's data.-Paul- (talk) 21:12, 11 February 2008 (UTC)

• disagree - I hate Geocentricity, too many mistakes (especially by astronomers) are made from that presumptous perspective. GabrielVelasquez (talk) 22:34, 14 July 2009 (UTC)

Requested move (2008)

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

Moved to List of extrasolar planets, with no prejudice against a further move to List of confirmed extrasolar planets should a narrowing of this list's scope be undertaken.--Aervanath lives in the Orphanage 05:11, 23 December 2008 (UTC)

---

List of stars with confirmed extrasolar planets → List of extrasolar planets — This page is currently functioning more as a list of extrasolar planets than a list of stars with extrasolar planets. In addition there is ambiguity about what constitutes confirmation, which may be taken to imply that these planets have been verified by independent observations, or that their planetary nature is confirmed (not necessarily true for radial velocity planets, particularly in single-planet systems where there are no dynamical upper limits on the masses). Furthermore, the current title excludes free-floating planets which have occasionally been requested by users to be included in the article. Moving to this new title would remove the potentially misleading implications of the word "confirmed" and allow inclusion of the free-floating planets. — Icalanise (talk) 18:56, 17 December 2008 (UTC)

Survey

Feel free to state your position on the renaming proposal by beginning a new line in this section with *'''Support''' or *'''Oppose''', then sign your comment with ~~~~. Since polling is not a substitute for discussion, please explain your reasons, taking into account Wikipedia's naming conventions.

• Support I agree that we should move to simply list of extrasolar planets; I like this proposed name better than list of stars with confirmed extrasolar planets. I see that the article name include 'confirmed' is misleading. Also it is better not including 'star' in title name. Moving this page would be consistent with the related articles list of unconfirmed exoplanets and list of brown dwarfs. Note the usage of the word 'unconfirmed' in list of unconfirmed exoplanets is important as this article lists exoplanets that are not confirmed. --BlueEarth (talk | contribs) 19:54, 17 December 2008 (UTC)
• Oppose It should be List of confirmed extrasolar planets, to go with the unconfirmed list. 76.66.195.159 (talk) 09:35, 18 December 2008 (UTC)
• Support I like list of confirmed extrasolar planets. List of extrasolar planets can be disadvantageous because it mean the list of confirmed and unconfirmed exoplanets. If we rename it to list of extrasolar planets, then we got to merge list of unconfirmed exoplanets into this proposed renamed article, like we see in list of brown dwarfs, which list confirmed and unconfirmed brown dwarfs. BlueEarth (talk | contribs) 17:42, 18 December 2008 (UTC)
• Support I prefer shorter titles, and unconfirmed planets are not really planets. Ruslik (talk) 11:09, 18 December 2008 (UTC)
• Support The table is really driven by planet additions rather than host star additions. A simple introductory note and table category can point out what their discovery status is. LostLucidity (talk) 18:47, 18 December 2008 (UTC)

Discussion

Any additional comments:

• The reason for dropping the "confirmed" part is that most of the objects that are listed here are not in any way confirmed planets: the majority are low velocity semi-amplitude companions to stars for which a good case has been made that they exist, but can only be termed planets on probabilistic grounds that they aren't in fact in the brown dwarf or stellar mass range, and the many have not been subjected to followup by independent observations. If we say an object is a "confirmed" planet, that presumably means it is confirmed that it exists, and confirmed that it is a planet. The latter criterion means we have to transfer all the objects without confirmed planetary masses off to the "unconfirmed" page, despite the low probabilities involved for most of these objects that they are not in the planetary mass range. For the objects that survive such a cull, we then need to decide what constitutes confirmation: is having independent datasets enough (e.g. transits+RV), or do we also need an independent team to confirm the first team's work? In which case we'd probably be down to a dozen or so planets left here. I don't think the requirement of "confirmation" is particularly helpful for this list. Icalanise (talk) 18:03, 18 December 2008 (UTC)

The above discussion is preserved as an archive. Please do not modify it. Subsequent comments should be made in a new section.

Individual planet comments

HD 154345b

The parameters for this planet could do with updating... seems to be a Jupiter-analogue in a circular orbit. See The Jupiter Twin HD 154345b and the Extrasolar Planets Encyclopaedia entry. The HD 154345 and HD 154345 b articles need an update too. 131.111.8.96 (talk) 09:55, 12 March 2008 (UTC)

HD 40307

Please add info on the newly discovered triple planet system of HD 40307. Thanks 82.16.1.141 (talk) 01:38, 17 June 2008 (UTC)

Please reply to my question here. Crystal whacker (talk) 03:12, 2 January 2009 (UTC)

HAT-P-7 link sends me to "HAT-P-7 b" redirect

Which containeds a redirect link to "HAT-P-7b", which works when I click it. Therefore I changed the table link for the star "HAT-P-7" to "HAT-P-7b" (piped) so that a reader gets to see the planet page instead of a confusing redirect page. I guess the star page has not been made yet? -84user (talk) 03:55, 3 July 2008 (UTC) changed tense to past-84user (talk) 03:57, 3 July 2008 (UTC)

Confusing isn't it? I am working on all of the references between the star and planet names for a couple of projects such as HAT, TrES and CoRoT. I have finished TrES (see the TrES Talk page for notes on the naming rules used) and I am now working on HAT. I hope to have correct designations for the planets, stubs for all of the parent stars and more meaningful redirection for these articles in a week or so. BTW - a parent star article exists for HAT-P-7b at GSC 03547-01402. I think the redirection from HAT-P-7 should be to the planet article and the general catalog designation (HD, GSC, etc.) for the star should be used for the exoplanet list's 'Star' column, if one exists. Please let me know if there are other redirects that are broken and I will add them to the list. Aldebaran66 (talk) 19:49, 24 April 2009 (UTC)

Confirmed planets by other-than-transit

There was an article back in 2001 which claimed to have the inclinations of 55 Cancri c and HD 192263 b among others. Han, I.; et al. (2001). "Preliminary Astrometric Masses for Proposed Extrasolar Planetary Companions" (PDF). Astrophysical Journal. 548: L57–L60. doi:10.1086/318927. {{cite journal}}: Explicit use of et al. in: |author= (help) We've since made more checks of the inclinations of HD 192263 b, and of 55 Cancri d and so probably c as well, which proved the prelims to be WAY off. But I think we're close enough to inclination to get us the mass for these planets. It's now time to promote them - probably gamma Cephei Ab too - like we promoted upsilon Andromedae b.

(Also, I reorganised the discussion a bit, because the chaos of the original was giving me a headache) -- Zimriel (talk) 18:52, 12 August 2008 (UTC)

Okay, I did the deed for 55 Cancri d and Gliese 876 b. c.f., [Benedict, McArthur, & Bean]. As for the rest - yeah, I guess we need to await their future publications. --Zimriel (talk) 18:42, 28 August 2008 (UTC)

• It appears most of the results in the Han paper were due to systematic errors in the reduction procedure. See [1]. Note also that the Han paper appears to be referring to 55 Cancri b (which is the second planet in order of distance), not c.
• Regarding the Gliese 876 astrometry result, it conflicts with the inclination from radial velocities and taking planet-planet interactions into account, e.g. [2]. Furthermore the astrometric reduction was done assuming Gliese 876 b was the only planet in its system: the 2:1 resonance hid the planet c as excess eccentricity in the orbital solution for b, so this might be suspect. Going from RV measurements, we can probably promote both Gl876b and Gl876c.
• It should be ok to promote the Gliese 581 planets based on [3] which excludes i<10° - which is sufficient to constrain the true masses to the planetary range.
• Tau Boötis b also has a weak constraint on the true mass by assuming it rotates in the plane of its star's equator (reasonable since the star appears to be tidally-locked to the planet), see [4]. Icalanise (talk) 19:04, 15 September 2008 (UTC)

HR 8799

Can someone please add HR 8799 to the list? It is currently an orphaned article(!) but absolutely requires a link on this page. Sorry, but editing the list is beyond my skills... --210.248.139.34 (talk) 02:14, 14 November 2008 (UTC)

Lalande 21185

The main entry suggests Lalande 21185 has planets but there's nothing on either here nor the list of unconfirmed extrasolar planets. I don't know enough about the research to know whether they're confirmed or not, and so whether they should be listed here, but someone who does can include it on either list. 92.40.144.141 (talk) 00:22, 17 January 2009 (UTC)

Given the star's absence in the Extrasolar Planets Encyclopaedia and the lack of a refereed publication of the detection (despite being 12 and a half years since the conference announcement), I'd say the Lalande 21185 planets belong in the unconfirmed extrasolar planets article. Icalanise (talk) 00:59, 17 January 2009 (UTC)

Thought as much but preferred to leave judgement to someone with more familiarity with the astronomical literature. Presumably it gets the attention it does because Lalande 21185 is one of our nearest stars. 92.40.144.141 (talk) 02:30, 17 January 2009 (UTC)

Gliese 581

According to Gliese 581, it has 3 (now 4) planets, not only "candidate planets". The corresponding lines should be moved to the right table. --Roentgenium111 (talk) 12:50, 21 April 2009 (UTC)

Restructuring discussion

Would be good to get feedback on how this article can be improved. I've placed below two sections where discussion of this was started, would be good to get feedback from the wider community here. Icalanise (talk) 21:21, 9 July 2009 (UTC)

Structure, inclusion criteria and referencing

Just thinking about various ways this list could be improved, would be good to get some opinions on the following...

• (1) Is the separation of planets for which true mass estimates are available versus those which don't useful? Furthermore is having a different set of fields for each table a good thing?
• (2) Are all the fields in the tables necessary? For a start, too many fields causes problems on smaller monitors. Which fields could be eliminated? Are there any fields which are missing that would be useful?
• (3) Bearing in mind the "references needed" tag on this article, what is the best way to do referencing? An extra table column, like on list of unconfirmed exoplanets? Anything else?
• (4) Is the 13 Jupiter mass cutoff a good idea? Does it make sense when weighed against the sin(i) degeneracy of most of these objects? Does it make sense when this criterion is not universally accepted by scientists working in this field?
• (5) What exactly constitutes confirmation?
• Any other issues?

Icalanise (talk) 21:53, 4 July 2009 (UTC)

Thanks for starting this discussion: these are all good issues that need discussing. In particular, as I mention below, I think the current separation into two tables based on availability of a true mass estimate is confusing and misleading, and that we would do better to simply have one big table in which the detection method(s) are indicated for each planet, with the accompanying text discussing the strengths and weaknesses of each method. The current approach encourages disorienting (and passive-aggressive) violations of WP:OR as editors shuffle planets between tables to reflect their prejudices. — Aldaron • T/C 19:09, 6 July 2009 (UTC)

This makes reasonable to me. Unless there is an English meaning for "candidate" that is not familiar to me, the seperate tables is just a cause of confusion. One table as described further on in this talk makes much more sense.

Another issue I'd add is whether to include artists conception images in the individual articles for the planets. This has been discussed elsewhere, but not (to my knowledge) resolved. Some editors seem uncomfortable with "favoring" a given artist (since any "impression" is pretty arbitrary), but I would argue that use of images supplied by official organizations associated with a discovery should be is fine, and should in fact, be encouraged (since for most of these planets they are the best impressions we will have for quite some time) as long at is made clear that the image represents an artist's impression of one possible form of the planet. — Aldaron • T/C 19:09, 6 July 2009 (UTC)

You want to cut this out and move it to a more appropriate place, there are no planet pictures in this article, so you muddle the discussion. GabrielVelasquez (talk) 05:04, 11 July 2009 (UTC)

Please start a conversation in the appropriate place then and link to it from here. Also it would be great if you could reference the previous discussions you mention on this topic, so we have some context and can understand better how the "consensus" against artists conceptions was reached. Thanks. — Aldaron • T/C 05:19, 11 July 2009 (UTC)

I'd rather keep the discussion here on the subject of this article, rather than policies for a whole bunch of other articles. Icalanise (talk) 10:47, 11 July 2009 (UTC)

I agree. Can you point me to where it should go? — Aldaron • T/C 13:20, 11 July 2009 (UTC)

(6) Error value ranges for the planet masses

best example is planet GQ Lup b / GQ Lup b is listed in the Extrasolar Planets Encyclopaedia (full spreedsheet) as a 21.5 Jupiter mass object when it is in fact (±20.5) anywhere from a 1.0 Jupiter mass object to a 42 Jupiter mass object. I find this also deceptive. I see the ranges in the individual planet article, but I don't want to see the same mistake made with these charts/lists at this article. Jean wrote me back and told me they were going to add the error values to his chart and to be patient; that was over a year ago. I know you want fewer columns, but I think this is an issue worthy of it's own column. GabrielVelasquez (talk) 05:12, 11 July 2009 (UTC)

Including error values are a great idea. I think including them would go a long way to cleaning up the confusion currently caused by multiple tables and the confusing categorization of "candidate" planets. In a single combined table we could let error values speak for themselves. — Aldaron • T/C 05:26, 11 July 2009 (UTC)

(4) Is the 13 Jupiter mass cutoff a good idea? Does it make sense when weighed against the sin(i) degeneracy of most of these objects?

All those objects above 13 times that of Jupiter listed in the Extrasolar Planets Encyclopaedia are found in list of brown dwarfs article. According to my planetary mass classification, 13 Jupiter masses is the upper limit to be classified as a planet, and 0.01 Earth mass is the lower limit. If an object more than 13 times that of Jupiter formed from circumstellar disk and core accretion like the planets do, it should still be classified as a brown dwarf, just like a star in binary system formed from the disk left over from the formation of a primary star. BlueEarth (talk | contribs) 21:21, 17 July 2009 (UTC)

Your planetary mass classification system doesn't count here. It's a bunch of Original research. In addition binary star formation is thought to be from fragmentation of the cloud as it collapses, not from formation from a disc. Can you provide references for why 13 Jupiter masses should be a hard cut-off? Examples where the distinction between brown dwarfs and planets becomes blurred includes the case of HW Virginis [5], HD 16760 [6], HD 202206 [7] and possibly also BD+20 2457 which hosts 2 objects with masses likely above 13 Jupiter masses close to the 3:2 resonance which are likely to have formed from a disc [8]. Furthermore there is this study [9] of the evolution of planets of various masses, which considers the possibility of planets more massive than the deuterium-burning limit but with rock or ice cores, and concludes "these results highlight the utter confusion provided by a definition of a planet based on the deuterium-burning limit." I do not think it accurately reflects the diversity of planetary systems to include the cut-off, when there are so many examples of where the real world disobeys the neat criterion. Icalanise (talk) 22:16, 22 July 2009 (UTC)

I agree with your point but don't see it as confusion just lack of research. I discovered how to calculate the irradiance on an extasolar planet from its parent star as a layman on my own with a little algebra and I don't think this is such a difficult issue, just lacking in expert scientific attention. What I mean is, for example, tidal lock zones are calculated for various star sizes, the "frost line" (irradiance on water) is calculated for various star sizes, and you seem to be insinuating that the same type of calculation can not be made so as to catagorize a planet that has an ice core even though that same planet would not have an ice core if it were on it's way to becoming a Chthonian planet, for example. In short I am saying the criterion you are refering to is too simple, at present. There are some red "supergiants" that are smaller than "main sequence" (O/B) Blue stars, but that hasn't stopped scientists from catagorizing them, no? I mean I like doing that kind of chart but would the formula be published if I did the math. You are better equiped to do the math, but instead you lean toward bash the effort. Give it shot, add the extra dimension and see if you can't come up with a Hertzsprung–Russell type diagram for classifying planets vs Brown dwarfs. Am I just saying Deuterium burning doesn't depend only on mass?...I guess I am.
I'm tempted to keep thinking outloud (babbling) on this one but I think you're smart enough to get me. Criterion refinement, or criterion elaboration, or ...criterion bedtime? GabrielVelasquez (talk) 11:35, 15 August 2009 (UTC)

Also could you define what you mean by "the sin(i) degeneracy" and how that contrasts?? It would help some of us help the solution along to know the difference. GabrielVelasquez (talk) 11:45, 15 August 2009 (UTC)

Current Candidate/unconfirmed/confirmation structure: confusing (and misleading)

The current organization, which distinguishes between planets and "candidate" planets is confusing and misleading. It implies that we either know less about the latter companions than we do, or that the data characterizing them (or the quality of the science behind them) is suspect. I propose that we reorganize the tables strictly by detection method, and rely on the text to clarify the advantages and disadvantages of each and the combinations of method and mass estimates that could result in a "mis-categorization" of a non-planet companion as a planet. — Aldaron • T/C 05:39, 6 July 2009 (UTC)

The extrasolar planet candidates section contains most of the planets detected by radial velocity method while extrasolar planets section contains most of the planets detected by transit method. BlueEarth (talk | contribs) 22:08, 6 July 2009 (UTC)

Yes, that's the point: the way it reads now, transit == real planet, radial velocity == doubtful planet. I think we'd be better off to just combine the tables, indicate the detection method there, and note the issues with each method in the text. — Aldaron • T/C 22:19, 6 July 2009 (UTC)

The issue of what is a "Candidate" planet and what is a "confirmed" planet and what is an "unconfirmed" planet are linked together. I don't yet see it as just a detection method issue, unless I am missing something, as with the example above, GQ Lup b, if this is a confirmed object it is sure is a rough and ugly estimate if it could be anything from "Jupiter size" to 42 Jupiter mass object. Maybe someone could explain why Jean has them laid out this way (catalog)???

• All Candidates detected 353 planets
  • Candidates detected by radial velocity or astrometry: 278 planetary systems /update : 01 July 2009 327 planets /34 multiple planet systems
    • Transiting planets 59 planetary systems /update : 01 July 2009 59 planets / 0 multiple planet systems
  • Candidates detected by microlensing 7 planetary systems / update : 19 September 2008 8 planets / 1 multiple planet systems
  • Candidates detected by imaging 9 planetary systems / update : 24 November 2008 11 planets / 1 multiple planet systems
  • Candidates detected by timing 4 planetary systems / update : 25 November 2008 7 planets / 2 multiple planet systems
  • Unconfirmed, controversial or retracted planets / update : 16 June 2009
  • Candidate "cluster" and "free-floating" planets
    • GabrielVelasquez (talk) 23:01, 11 July 2009 (UTC)

I'm fine with calling them all "candidates"; or calling them all something else. The issue is that the current tables make a distinction between "candidate" and others (a distinction not made by "Jean"). If you're suggesting we follow the schema you quote above: one list, all of which are called candidates, with the detection method indicated, then I'd absolutely support that. — Aldaron • T/C 01:04, 15 July 2009 (UTC)

Sure, you know what Schneider meant. He is clearly making a distinction by using the terms "Candidate," "Unconfirmed," "Transiting" and even others still (controversial or retracted) as you say he is not. He may have started this confusion because his layout may have been misinterpreted, but I see that he is making the detection method a distinction between the "candidate" planets (although that organization took me a while to get) and that may be a better way of distinguishing them as long as you don't insinuate that a cruise ship is now taking reservations as some other editors have done from the suggestion that a planet in question is perfectly Earth-like and absolutely there. The layout he uses is a good suggestion I think as long as you have (as I said before) the mass possibility/error range. So, yes your initial suggestion was fine, except that it wasn't the "Candidate" concept that you should have been bashing, But rather clarifying what anyone would mean by the unused term "Confirmed" and I believe Icalanise set himself that task. Most of this debate hinges on that, why is Schneider using "Candidate" instead of "Confirmed?"GabrielVelasquez (talk) 11:02, 16 July 2009 (UTC)

One point is that the Catalog of Nearby Exoplanets doesn't bother with "candidate", but lists anything with low m sin(i) as a planet. This is of course problematic - RV planets have low but non-zero probabilities of being brown dwarfs or even stars (case in point HD 33636b which turned out to be a red dwarf star rather than a 9 Jupiter mass planet). I brought up the issue of confirmation issue because of the split between this list and the list of unconfirmed extrasolar planets, which seems fairly arbitrary: we've got objects in here that are unpublished in peer-reviewed journals. Directly detected planets have masses which hinge on evolutionary models and in several cases have suspiciously wide separations or low mass ratios which may indicate they are brown dwarfs (depending on how you define the term - the 13 Jupiter mass limit, deuterium fusion, or formation). One point is that some things definitely lead to the conclusion that what we are dealing with are planets - for example having 2 or more companions in a non-hierarchical relationship is a pretty good case (though hierarchical systems are more ambiguous): I'm not sure that you'd find many who would argue against the planetary nature of the five companions in the 55 Cancri or HD 69830 systems for example, despite the lack of true mass estimates. I'm not entirely sure myself what is the best way to handle this hence my starting the RfC in the first place. Icalanise (talk) 19:36, 16 July 2009 (UTC)