Talk:List of largest exoplanets

About confirmed planet but with radius uncertain (theoretical estimate or just estimation)

i saw someone attempting to add some planets with those with theoretical radius estimation or those with estimated radius (but not confirmed?) but then got remove because of radius unknown or theoretical. since we already have "Exoplanets with uncertain radii" section, can also add those with radius uncertain even the radius is below 1.6Rj and/or not under ranges of radiuses? @SoojinHD219134star Foxy Husky (talk) 02:31, 26 December 2025 (UTC)

some values are only roughly guessed, as the method used does not allow a measurement and other values (e.g. age) need to be guessed as basis for the radius guess and in addition the measured values also do not allow a direct calculation of the radius. We usually only added objects that have at least one measurement value above 1.6 RJ, even for the uncertain cases. The questions you raised are very good. We should, however, consider whether we delete objects whose discovery method does not allow to infer a radius of the object even with additional such measurements in the future. What I mean is: Should we keep objects, for example discovered by radial velocity, whose radius can never (or for a very long time) be calculated, except they are also found transiting, are directly seen, seen in reflection, ... ? Stevinger (talk) 00:43, 29 December 2025 (UTC)

Since the question was raised. We have different categories (roughly):

• 1) Calculated radius from measurements of a confirmed companion above 1.6 RJup
• 2) Radius from modelling of a confirmed companion above 1.6 RJup based on solid input parameters
• 3) Uncertain radius from several measurements of a confirmed companion above or below 1.6 Rjup
• 4) Radius of an unconfirmed/disputed companion above 1.6 RJup
• 5) Unknown radius of a confirmed companion that was already measured by a method that can determine a radius
• 6) Unknown radius of an unconfirmed/disputed companion that was already measured by a method that can determine a radius
• 7) Radius of a confirmed/unconfirmed/disputed companion that is based on estimated/guessed modelling input parameters
• 8) Unknown radius of a confirmed companion that was not yet measured by a method that can determine a radius
• 9) Unknown radius of an unconfirmed/disputed companion that was not yet measured by a method that can determine a radius
• 10) Radius of a confirmed companion below 1.6 RJup
• 11) Radius of an unconfirmed/disputed companion below 1.6 RJup

I would personally include 1) to 4), would have no problem if you want to continue to include 5) and 6) and would exclude 7) to 11), except notable confirmed examples below 1.6 RJup that we have.

What are your opinions (@Foxy Husky, @21.Andromedae, @SoojinHD219134star, and of course anybody) ? Stevinger (talk) 23:26, 1 January 2026 (UTC)

Regarding radii that were not measured but guessed from their masses (like those given in 'NASA Eyes on Exoplanets' for RV-only planets), i do not object with their removal, since these guesses should be viewed with a grain of salt as the sizes of 'cold' objects over 1 M_J increase slightly and stop increasing after 1.2 R_J, so the radii of these objects could easily be anything between 1.0 and 1.2 R_J, which is a non-negligible range, and combined with the fact that RV only detects m sin i, these radii aren't really credible. So, i think that preference should be given for objects with measured radii (3, 4), even if they are based on most basic methods like evolutionary models. But frankly, adding objects as candidates for the largest exoplanets when their radii are unknown (5, 6, 7, 8, 9), even though their mass is over 1 M_J, is stretching it and pushes the concept of a 'list of largest exoplanets' to the limit, while adding planets fitting (10, 11) is an absurd. I guess that (1, 2) refers to taking the radius of a similar companion Y to an object X, if such an assertion is made in the reference this can be added. 21 Andromedae (talk) 23:54, 1 January 2026 (UTC)

personally, i would include 1) to 5), and 7) (confirmed only) since the radius can be estimated based on transit or whatever methods that provide rough estimated radius. this qualifies them as "confirmed planet but with radius uncertain".
for 6) and 7), we can just put them under candidate list.
for 8) and 9), since theres yet way to measure by determining a radius, we cannot include these lists.
for 10) and 11), we can just put them inside with an extra row for "Planet with noticeable <insert things>" or maybe not include them at all Foxy Husky (talk) 08:01, 2 January 2026 (UTC)

@Foxy Husky @21.Andromedae I agree with Stevinger's choice, which accepts categories 1 to 6 and rejects other categories. However, the number of notable objects with radius below 1.6 R_Jup and other objects for reference with radius above that should be limited to a few dozens.SoojinHD219134star (talk) 14:58, 4 January 2026 (UTC)

@SoojinHD219134star @Stevinger since we alr hv Saffar's radius estimated using the phase curve of reflected light, can this planet put under list of "Confirmed Planet but with radius uncertain" or just leave it on main list? Foxy Husky (talk) 15:05, 4 January 2026 (UTC)

I would suggest to keep Saffar in the main list. The radius estimation using a phase curve is a valid method, while not very common. A slightly similar estimation was presented for Dimidium. While for Dimidium it was challenged, for Saffar it was not. Since there is also no much lower radius estimate (like for Dimidium) I do think it is not well suited in the "Confirmed Planet but with radius uncertain" category. The method uses assumptions, but other methods do that, too. Stevinger (talk) 05:39, 9 January 2026 (UTC)

thank you for your answers. If I read all your answers correctly then it was close, but there is a slight consensus to include categories 1 to 6 for the moment. Indeed I meant with category 2 anything that was not measured and calculated, but by comparison or simply using evolutionary models, which are sometimes not perfectly calibrated, ... but are mostly reliable estimations. With category 7 I meant e.g. estimates like in the https://science.nasa.gov/exoplanets/exoplanet-catalog/. While in general a good catalog the larger size of some imaged companions caused by their youth was often neglected and the radius estimates in the past were sometimes very different from what evolutionary models expected. Or of course the example 'NASA Eyes on Exoplanets' 21.Andromedae gave, which I was not aware of. I will adapt the small changes that are needed in the candidates lists step by step and give individual reasons in the edit summaries. Please correct me, if something is wrong.

Category 5 and 6 might be a slight stretch, but I hope that they are a small list of upcoming objects. E.g. Mu² Scorpii b and Mu² Scorpii c just made it out of category 5 and 6 into the top 4 categories (mentioned above). Similarly e.g. CHXR 73 b has a probability that it is a unrelated member of Chamaeleon I of only ~0.1%, similarly secure then some RV planets and has luminosity and spectral type available, so a radius might be soon available.

The new category 'Exoplanets with known estimated radius of ≥1.6 R_J' in the 'Exoplanets with uncertain radii' list is unfortunately not correct as both objects are clearly below 1.6 RJ, but I will check what we can do with them or whether they need to be removed as objects below 1.6 RJ (corresponding to category 10 above).

Finally I will for the moment delete the added Kepler-90g. A warning was previously introduced stating 'DO NOT ADD MORE PLANETS WITH RADIUS LESS THAN 1.0 JUPITER RADIUS TO THE LIST WITHOUT CONSENSUS' (commented out, only visible while source editing). Of course it can be added if several of you want to have it. I personally don't think an object below Saturn's radius belongs into the list, this feels like a stretch to me for a list of largest exoplanets. The present workpage has, however, a separate list 'Terrestrial planets'. I do not want to rule out such separate lists if several of you want to add such a list or a similar list and you think there is interest of people in it. Stevinger (talk) 18:34, 9 January 2026 (UTC)

ooooo i dunno the workpage exists as separate article but since its somewhat related to Kepler-90g, can we create the list for those with radius larger than one R_🜨 or whichever higher, and less than radius of Saturn Foxy Husky (talk) 06:44, 10 January 2026 (UTC)

After reading about the list description I realized Kepler-90g also does not fit the current description the list only includes gas giants, as Kepler-90g is given to be between the masses of Uranus and Neptune, so rather an Ice giant. This is connected to your question. A clear definition would be needed for another (sub)list, like the 'terrestrial planets' in the workpage. There are many possibilities, like e.g. Terrestrial planets, Super-Earths, Mega-Earths, Sub-Neptunes, Mini-Neptunes, Super-Neptune, Sub-Saturns, Ice giants. The problem is that similar to the current main list, the members of the list are hard to identify, in the current main list it is difficult to distinguish them from low mass brown dwarfs, in a terrestrial planet list Neptune-like planets, that formed differently, should not be included, though being larger. In an Ice giant list knowing an object is not a gas giant if very large seems very difficult or even impossible in many cases. Stevinger (talk) 01:50, 11 January 2026 (UTC)

for some reasons, HAT-P-67 Ab's mass is way too low for the planet with the radius of around 2 R_J which technically qualify as sub-saturns....? anyway.... since theres some ice giants in main list, then can add like.... "Ice giant" or something like that under Key (Classification)? Foxy Husky (talk) 06:06, 11 January 2026 (UTC)

you are right, Hat-P-67 Ab is pretty low in mass for its size, but it is very likely still between Saturn's mass (0.299 MJup) and Jupiter's mass with its 0.45 ± 0.15 MJup, so seems fine. Our ordering of mass in the table seems to work fine and tells me after clicking on it, that only WASP-127b, Bocaprins and IRAS 04125+2902 b are likely less massive than Saturn. While Bocaprins is basically equal in mass to Saturn, WASP-127b and IRAS 04125+2902 b seem to be in the mass region where they are more likely Ice giants. Since both are only mentioned in the notability section I think it is fine, no adaption necessarily needed. Stevinger (talk) 03:05, 12 January 2026 (UTC)

Gas giant planets or Giant planets

@Stevinger @21.Andromedae about the comments regarding gas giants and ice giants from the previous topic, i did add some planets that not even under gas giants but quite noticeable. because it conflicts with "gas giants" list, i would propose changing from gas giant planets to giant planets which in general are huge planet gas with any atmospheric material so that those giant planets with the radius more than Saturn's can be added into the list Foxy Husky (talk) 15:37, 24 January 2026 (UTC)

I thought about it and I am not sure if it is necessary. At the moment only WASP-127b is not a gas giant. I would rather propose to check whether there are several objects that are too low in mass to be a gas giant and are high enough in radius to be relevant for the list. If there are several very interesting objects, especially above Jupiter's radius, I would suggest to change it. If there are only 1 or 2 halfway notable objects below Jupiter's radius left, I would suggest to not adapt it. Are there other opinions? Stevinger (talk) 10:42, 26 January 2026 (UTC)

@Stevinger Your move seems reasonable. Not only WASP-127b, IRAS 04125+2902 b and WASP-39b are also even less massive than Saturn despite their large radius, thus they should be more properly called "Super-Neptune" or "sub-Saturn" instead of "gas giant". However both of them are interesting objects with milestones, which makes me feel reluctant to remove from the table :(( SoojinHD219134star (talk) 15:32, 27 January 2026 (UTC)

Thank you. I forgot about these ones (^_^)'. Then it seems reasonable to follow the proposal of Foxy Husky and change/move to giant planets, while I suggest to keep only adding milestone and superlative objects for very low-mass objects. Stevinger (talk) 18:45, 27 January 2026 (UTC)

but lets say we hv one planet with the radius of 1.6 R_J but hv mass of like.... 0.2 M_J.... would u add this planet because of the list qualification of hving the radius of equal or more than 1.6 R_J while ignoring the two words "gas giants"? imo this planet is disqualified because of the mass but still qualify because of the radius which create paradox since the article focus on radius while keeping the planet's mass under 30 M_J. Foxy Husky (talk) 11:42, 28 January 2026 (UTC)

Yes, I would add it. I do think that radius should be more important than mass. As SoojinHD219134star wrote there are already two objects with "sub-Saturn" mass in the list, that have radii above a Jupiter radius and are objects with milestones. This is why I suggested to follow your proposal and change gas giant → giant planet. I just meant that I hope we stick to the milestones and superlatives, especially in the cases radii are below a Jupiter radius. Stevinger (talk) 07:21, 29 January 2026 (UTC)

DH Tau b

Xuan et al. (2024), the given reference, states this is likely a brown dwarf instead of a planet, as is with every other PMC in this study. Any objections before I edit it as such? ~2026-11618-07 (talk) 03:21, 22 February 2026 (UTC)

Yes, I do object. At least at the moment for several reasons, which might change, of course, in the future as new results arrive. Let's start for the easiest reason: I checked again in Xuan et al. (2024) every mentioning of DH Tau b and they do not state this is likely a brown dwarf instead of a planet. If you object, please provide where they do so. Thank you. Stevinger (talk) 08:59, 22 February 2026 (UTC)

It’s not called a brown dwarf directly but the paper does conclude that the objects of study are brown dwarfs.

“Thus, the population of low-mass substellar companions from direct imaging likely traces the tail end of star formation processes such as gravitational disk instability and cloud fragmentation, making them low-mass brown dwarfs instead of “super-Jupiter” planets or “planetary-mass companions.” ~2026-11618-07 (talk) 23:23, 22 February 2026 (UTC)

Thank you. That explains what you meant, however, not what the authors meant:

• The situation for DH Tau b is not as 'solid' as for the other objects, e.g. it has only 'a tentative detection of 13CO for DH Tau b'.
• Directly after your citation, they write 'Alternatively, we note that our composition measurements are also consistent with core accretion outside the CO snowline where these companions are observed today, since accretion at these locations would also yield stellar C/O and metallicities.'
• gravitational disk instability seen as pure star formation process is not the most common view. E.g. see here that Wikipedia mentions it as planet formation process. Or if you prefer outside material, see e.g. here in which a 'jovian protoplanet' is mentioned and that its existence 'may also provide the evidence for a long-considered alternative to the canonical model for Jupiter's formation: disk (gravitational) instability'. Or maybe a short interview with a MIT professor on the topic here.
• this means DH Tau b is likely formed by a planet formation/star formation process (gravitational disk instability) or a star formation process (cloud fragmentation) or alternatively by another planet formation process (core accretion). This brings me to the main argument:
• The list for such reasons does not include formation processes as reason for the nature of an object, because they are yet very uncertain. DH Tau b is currently given as probable exoplanet (≲ 13 M_J) (based on mass) in comparison to the deuterium burning limit. Xuan et al. (2024) give a most likely mass of 12 Jupiter masses. I agree, the mass is close to the limit, but for the moment it seems fine. Please tell me if they somewhere prove that disk instability can only form brown dwarfs and stars. Then the situation would be different.

Stevinger (talk) 12:09, 23 February 2026 (UTC)

In your second point, it also mentions “However, such a scenario requires core accretion to proceed early and rapidly in a massive protostellar disk in order to explain the accretion of 10–30 MJup of material, especially for the systems with lower-mass host stars.” straight after that comment. How do you address this? ~2026-12071-06 (talk) 01:14, 24 February 2026 (UTC)

That is very true. As given in your citation and my fourth point (just summarizing), this makes a formation by gravitational instability or cloud fragmentation likely. There might be more time to form it though with core accretion, too. More or less every other reference finds a higher age than 0.7 Myr. Let's see what future references find. Stevinger (talk) 10:50, 24 February 2026 (UTC)

Nominal Jupiter radius

Thank you for updating the Jupiter radius @Foxy Husky.

I think the radius as being very recent is perfect as the radius given for Jupiter itself. However, I would recommend to change for the other mentions back to the nominal Jupiter radius. There is an IAU resolution for it, please see here. They recommend to use exactly 71 492 km as radius for Jupiter to make values given in Jupiter radii comparable with each other.

The wiki page of Jupiter radius expresses it this way:

Density fluctuations within the planet can create variations in the equatorial radius of up to 30 km. The winds in Jupiter's outer atmosphere can vary the radius by up to 4 km.

In 2015, the International Astronomical Union defined the nominal equatorial Jovian radius as a set number of meters, so that a commonly agreed value would remain constant, notwithstanding the subsequent improvements in measurement precision of Jupiter's radius. This 'constant' is defined as exactly:

= 7.1492×10⁷ m

Stevinger (talk) 08:39, 22 February 2026 (UTC)

ok.... i change back to the IAU recommendation though i add the note to that one about the recently updated radius Foxy Husky (talk) 12:49, 22 February 2026 (UTC)

Blanet

@Stevinger @SoojinHD219134star i actually thinking of adding the "theoretical planet size restrictions" for blanet, a planet that orbits around black hole or binary object and black hole, since the blanet itself a hypothesis objects that has some radius and mass limit during its young age or something. not too sure if we can add the theoretical blanet size restrictions since the SMBH has very high crazy masses but for the small black holes, i can assume that the planet can form with size limitation like normal stellar system? Foxy Husky (talk) 10:00, 29 June 2026 (UTC)

I fear I cannot follow what you meant. To be honest I have never read about a size limit for blanets. Did you find a theoretical limit somewhere? Stevinger (talk) 21:55, 30 June 2026 (UTC)