Talk:List of largest exoplanets

Ranking

The ranking makes no sense, the ranks listed here only concern the entries list here, and not the ranking of all known planets. Therefore I am removing ranking -- 67.70.35.44 (talk) 07:59, 7 November 2014 (UTC)

HD 100546 b

This radius is almost certainly wrong; the object seems to be surrounded by a protoplanetary disk. I cannot find any original source for this radius in the papers. There's no way it has a radius more than 6x that of Jupiter. This may be a typo of its semi-major axis. Removing pending someone finding a better source. Titanium Dragon (talk) 00:57, 26 February 2017 (UTC)

There is a rediable source which mentions the radius of HD 100546 (6.9 R_J). see: Confirmation and characterization of the protoplanet HD100546 b - Direct evidence for gas giant planet formation at 50 au. Ynoss ^(talk) 18:45, 22 May 2017 (UTC)

Actually, HD 100546 b might actually be a brown dwarf. According to planetary evolution and physics models, there is no planet with a diameter of 350,000 km or more. Thus ROXs 42 Bb, GQ Lupi b and HD 100546 b might actually be brown dwarfs. Thus it would be improper to say that they are the biggest planets, and CT Cha b (316 000 km) will get the record for now. --Joey P. - THE OFFICIAL (talk) 03:35, 14 July 2017 (UTC)

No. HD 100546 b, ROXs 42Bb and GQ Lupi b are planets because they are not massive enough. To be brown dwarfs, they must have a mass greater than 30 solar mass.Thank you— Ynoss du 44 Pro ★ ✉ / _CONTRIBS 05:58, 14 July 2017 (UTC)

im going to add hd 100546 b into this so people can think the radius is right 2600:1700:82B0:7480:3D45:583F:9438:96B7 (talk) 00:43, 18 August 2023 (UTC)

GQ Lup b

In the paper sourcing its radius, this "planet" is estimated as having a mass of ~20 M_J, which would make it a brown dwarf, not a planet, and the paper notes that it is probably a brown dwarf but that they cannot rule out that it might be smaller. Removing it for now; feel free to argue with me if you've got a good reason why this should be here. Titanium Dragon (talk) 01:15, 26 February 2017 (UTC)

List of most massive exoplanets say that the most massive exoplanet is DENIS-P J082303.1-491201 b with a mass 28.5 M_J so the maximum mass of a planet is 30 M_J. Ynoss ^(talk) 18:55, 22 May 2017 (UTC)

Radii

Please reconsider the given radii. An old planet cannot have a radius of 3 - 4 times Jupiter's. Please see http://beyondearthlyskies.blogspot.fr/2015/07/classifying-planets-brown-dwarfs-stars.html figure 3. There is a reason why e.g. for HD 87883 b neither exoplanet.eu http://exoplanet.eu/catalog/hd_87883_b/ nor NASA exoplanet archive https://exoplanetarchive.ipac.caltech.edu/cgi-bin/DisplayOverview/nph-DisplayOverview?objname=HD+87883+b&type=CONFIRMED_PLANET give a radius, since RV planets only have a radius determined if a transit is observed, which I assume is not the case here. Directly imaged planets can have a radius, coming from luminosity / age / temperature. Very young planets still contract, thus are larger. — Preceding unsigned comment added by Exowrite (talk • contribs) 13:23, 23 November 2017 (UTC)

@Exowrite: I think this source http://www.exoplanetkyoto.org/exohtml/A_All_Exoplanets.html is somewhere unreliable. Well, what I will do is remove all the planets mentioned in this source and add more planets that have radii larger than 1.7 R_J. ZaperaWiki44^{(✉/Contribs)} 08:33, 25 January 2018 (UTC)

Pictures, or no Pictures ?

I see that a particular IP address user does not want to have pictures in this list.

I see no reason for those planets not to be there.

1.) They aren't hurting anyone, and they aren't doing anything wrong staying there, are they?

And 2.) So what if it's a list, nobody said that pictures can't stay on a list. There is no law preventing pictures staying there. As far as I can see, you are just removing them because you don't like them.

Please clarify,

PNSMurthy (talk) 01:18, 20 July 2020 (UTC)

I want those images to Stay . I am undoing the edit. The descriptions likely stand no justice to the image. For HD 100546b, It says there is a disk around the planet, and the image shows that. --THE COLOSSAL GALAXY NAMED IC1101 (talk) 11:29, 21 July 2020 (UTC)

Indeed. There's no reason for them to go, so, why don't they stay?PNSMurthy (talk) 00:24, 23 July 2020 (UTC)

They SHOULD Stay. Scientific data and real pictures of exoplanets are basically a bit of blobby like appearance. Kind of ugly , right? So we want a better image, and that’s where the artist images are here for. Again, HD 100546b for example, The real image when you look at it you can’t see the planet and disk but using the artist’s impression, we can visualize an impression of the planet and disk. Also see the red orange and yellow color of HD 100546b means it is hot. Using Artist images, At least we are able to visualize a guess of how the planets look like. THE COLOSSAL GALAXY NAMED IC1101 (talk) 03:46, 23 July 2020 (UTC)

The problem is that they don't have really much use for the list and many are already used respectively in exoplanets' linked articles, despite replies here since there is no really much proper explanation. Some instead just show also the location of the objects within a planetary system, in which it feel as well useless for the list too. And what is even worse (aside from impressions just made-up by users as for WASP-76b), few used in the list are just a comparison with Jupiter by radius while using the exoplanet as the white sphere.

Speaking of HD 100546 b, it was honestly more reasonable to just remove it from the list (and it is already), the quoted radius was never meant to a single planatary radius but instead of the emitting area anyways. NASA Exoplanet Archive also is not as reliable as scientific papers (and also never stated HD 100546 b as the "largest exoplanet" despite being at the top of the list by radius), and has some strange and nonsensical results that are likely made-up, such as 752 M_J when one of the most recent researches placed a much lower upper limit of 1.65 M_J. Moreover the surrounding disk is also much larger with a radius up to 0.44 AU based on the same said study. Regards—ZaperaWiki44^{(✉/Contribs)} 01:18, 7 October 2023 (UTC)

A Commons file used on this page or its Wikidata item has been nominated for deletion

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Tell

Largest planet 223.235.189.226 (talk) 03:14, 29 March 2022 (UTC)

Remove HD 100546 b

This is the radius of the emitting area, not the radius of the actual planet and this is explicity mentioned in the source. Faren29 (talk) 16:03, 12 June 2022 (UTC)

HOW COME 2600:1700:82B0:7480:3D45:583F:9438:96B7 (talk) 00:41, 18 August 2023 (UTC)

HD 100546 b disputed

New analysis showed that signals from what appeared to be HD 100546 b were from a more diffuse structure.

The visible part of the source may not have been part of such planet itself, but the disturbance in disk caused by what appears to be a much smaller and further body (c) completely embedded in the dust shroud.

The 3rd candidate is not confirmed and seems obvious from the recent analysis of the previous disputations.[1] Eric Nelson27 (talk) 21:03, 11 June 2023 (UTC)

TYC 8998-760-1 b's status

TY 8998-760-1 is around 14 x the mass of Jupiter, with a margin of error of +/- 3 Jupiter masses, meaning there's a high chance it's a brown dwarf rather than a true planet.

To call it a planet may not always be truthful because the average mass is 14 Jupiters and it takes at least 13 Jupiters in mass for it to qualify as a brown dwarf.

TYC 8998-760-1 b is most likely a brown dwarf due to its mass. Eric Nelson27 (talk) 21:40, 16 June 2023 (UTC)

Rewriting the list

Hello. I wanted to let you know that I have made a workpage (or sandbox) to rewrite the list in order to make it better organized given this list is an overall mess.

See also the #Pictures, or no Pictures ? subject regarding the files used in the table, and why I disgreed from the beginning. Regards—ZaperaWiki44^{(✉/Contribs)} 16:41, 4 October 2023 (UTC)

RIK 72 b

i found this source [1901.05532] Age Determination in Upper Scorpius with Eclipsing Binaries (arxiv.org) saying RIK 72 b is around 3.10 Rj, is this reliable? ADudeWhoLikesAstronomy65141 (talk) 10:43, 29 January 2024 (UTC)

This source is likely reliable, however, this object could not be on the list because its mass (59.2±6.8 M_J) makes it obviously a brown dwarf. InTheAstronomy32 (talk) 16:31, 29 January 2024 (UTC)

Disputed bodies vs candidate bodies

The body HD 100546 b was added to the page again, and since it's disputed, I had to correct the page.

There are 2 candidate bodies, but none of them are named b, c, or d, and they have no radii estimated (yet they're not confirmed nor disputed at the time of this topic).

b, c, and d on the other hand are disputed.

Therefore, there are no known planetary-sized or substellar bodies orbiting HD 100546.

Anyone on here should be reminded not to add disputed objects on the page because that's evidence they don't exist. Eric Nelson27 (talk) 19:00, 2 April 2024 (UTC)

UScoCTIO 55

The object is also rogue like proplyd 133-353 and it is estimated around 4.9 Jupiter Radius with a mass of 10 Jupiter mass, sould we add it to the list? APerosn53248 (talk) 13:34, 20 July 2024 (UTC)

0.10 M_☉ according to this paper SpaceImplorerExplorerImplorer 20:15, 21 July 2024 (UTC)

that's the same mass i said 2A00:A041:E547:500:AD82:B4F3:62A0:21C7 (talk) 09:35, 11 August 2024 (UTC)

A New List

Sould we do instead of 1 list, 2 lists?, one being for exoplanets and one being for brown dwarfs/sub brown dwarfs? APerosn53248 (talk) 09:48, 30 July 2024 (UTC)

ROXs 42Bb

If we are using the best and most recent estimates (see caevats section), then ROXs 42 Bb should be at 2.83±0.01 R_J. 21 Andromedae (talk) 12:15, 4 August 2024 (UTC)

1.35 R_J should also be replaced with something more sensible such as 1.81 R_J, that uses the mass and surface gravity from the high-resolution retrievals. Actually i support putting the radius at 2.83 R_J, it is the most recent estimate anyway and is consistent with evolutionary models. 21 Andromedae (talk) 12:27, 4 August 2024 (UTC)

Removing HD 100546 b

there is no reason to add disputed bodies to the list if we know they don't exist so im removing it from now 2A00:A041:E547:500:78DB:3F9E:1B51:F418 (talk) 12:40, 7 August 2024 (UTC)

@2A00:A041:E547:500:78DB:3F9E:1B51:F418 What evidence is there for the planets non-existance? Infa 65 (talk) 20:12, 11 August 2024 (UTC)

[2] Stevinger (talk) 07:00, 13 August 2024 (UTC)

Sub-brown dwarfs vs. Rogue planets (PSO J318.5−22)

I first also wanted to write that we don't have a time machine, thus not knowing how PSO J318.5-22 formed. So both Sub-brown dwarf and Rogue planet should be linked. However, I realized a problem wiith the definition of both types of objects. In Sub-brown dwarf Rogue planets are defined as 'rogue planets, which originally formed around a star and were ejected from orbit', while in Rogue planets the objects are defined independent of the formation like a star or a planet. Having read the first type of definition, I assumed we don't know whether the object was ejected, so PSO J318.5−22 could be a sub-brown dwarf or a rogue planet. Vice versa, there is a similar problem with the definitions: In Rogue planets Sub-brown dwarfs are defined as 'Some planetary-mass objects may have formed in a similar way to stars, and the International Astronomical Union has proposed that such objects be called sub-brown dwarfs.', which is incorrect. In Sub-brown dwarfs they are defined as ''the IAU Working Group on Extra-Solar Planets (WGESP), which defined it as a free-floating body found in young star clusters below the lower mass cut-off of brown dwarfs.'

The problem can be solved consulting the most recent working definition of exoplanet. Either at [3] or at the Exoplanet page. In the 'List of possible sub-brown dwarfs' at Sub-brown dwarfs several objects are given 'orbiting one or more stars'. However, according to definition objects below 13 Jupiter masses 'that orbit stars or stellar remnants are "planets" (no matter how they formed).' So, either planets or brown dwarfs (if above the limit), never sub-brown dwarfs.

Similarly, '

• Free-floating objects in young star clusters with masses below the limiting mass for thermonuclear fusion of deuterium are not "planets", but are "sub-brown dwarfs" (or whatever name is most appropriate).

' So, also independent of formation. If an object is formed around a star like a planet and ejected, it is according to this definition a sub-brown dwarf. Also if it was formed like a star, ejected from a system or not.

This leads to the fact that 'Sub-brown dwarfs and rogue planets are not essentially the same thing'. This is corraborated twice in [4]. Once in section 4 'Future': ' At the end of item (3), the text: “sub-brown dwarfs” (or whatever name is most appropriate) should be updated to the currently accepted term “free-floating planetary mass objects”.' And even more clear in section 2.6.: 'For planetary mass objects that do not orbit around a more massive central object, the term “sub-brown dwarf” has not been adopted in the usage by the community; rather, these objects are often referred to as “free floating planetary mass objects”. These two terms are nowadays considered as synonymous'.

So, I strongly suggest to merge the two pages Sub-brown dwarf and Rogue planet. While it seems more work was invested into the latter page, a level-5 vital article below 'exoplanet' might be problematic, as is currently the case for the latter page, since '

• Free-floating objects in young star clusters with masses below the limiting mass for thermonuclear fusion of deuterium are not "planets"

'

This leads to follow-up difficulties, e.g. none of the objects in the List of directly imaged exoplanets can be a Sub-brown dwarf, since not free-floating, they are either planets or brown dwarfs, except the excluded free-floating planetary mass objects / free-floating planets / sub-brown dwarfs / rogue planets / ... . Stevinger (talk) 11:57, 8 August 2024 (UTC)

It seems surprisingly hard to find references for the original usage of 'sub-brown dwarf' (which confirms 'the term “sub-brown dwarf” has not been adopted in the usage by the community'[5]) and also to an extent 'rogue planet'. This explains the partly inconsistent definitions on the dedicated pages and a small amount of references therein.

The following two references could be added: 'One doesn't know if apparently "free-floating" planets which may have recently been discovered in Orion formed by self-collapse or by formation in a disk followed by ejection (Reipurth 2003)'[6] and: 'if it turns out that Jupiter has no real core and formed suddenly during a rapid gravitational instability in the protoplanetary nebula, that we have been mistaking a sub-brown dwarf for a planet all this time'[7]

The latter reference confirms that 'sub-brown dwarf' was used for objects formed like stars, also within a system, contradicting the current IAU working definition of exoplanet.[8] In this definition all objects below 13 Jupiter masses 'that orbit stars or stellar remnants are "planets" (no matter how they formed).' and 'free-floating objects in young star clusters with masses below the limiting mass for thermonuclear fusion of deuterium are not "planets", but are "sub-brown dwarfs" ' It also explains why the IAU working group explicitly wrote 'nowadays' in 'These two terms (sub-brown dwarf and rogue planet) are nowadays considered as synonymous'.

Should the definitions of the two terms be updated with additional references for the traditional meaning of the terms OR should the two articles be merged taking into account the IAU working definition of exoplanet and the two terms NOWADAYS considered as synonymous? Stevinger (talk) 05:28, 9 August 2024 (UTC)

Help

Im adding objects to the list but i thought the references mention the size and the mass, but i did put the link in and it putted a different reference 77.137.65.183 (talk) 20:04, 9 August 2024 (UTC)

That is weird, should not happen. If you post a link in the discussion, here, as reply someone can surely put it into the list. Stevinger (talk) 02:31, 10 August 2024 (UTC)

Proplyd 133-353

In this edit user 21.Andromedae states Re-added Proplyd 133-353, calculating a radius from temperature and luminosity is not wp:SYNTH (not anything else) per this discussion. Even if this kind of calculation is acceptable, there are two points to be made here:

• The footnote merely says Based on the estimated temperature and luminosity, it does not say how the values were calculated. So it is not reproducible.
• Proplyd 133-353 is a proplyd. Does its disk affect the values used here?

SevenSpheres (talk) 20:06, 10 August 2024 (UTC)

The footnote can be improved with the footnote used in Epsilon Indi Ab. 21 Andromedae (talk) 20:51, 10 August 2024 (UTC)

Somebody used the Stefan–Boltzmann law, please see 'examples', temperatures of 'stars', directly connecting luminosity, temperature and radius.

Yes, this might affect the values in this case. Especially, if the object is an evaporating gaseous globule (EGG), the chances are higher. It is, however unclear whether this is the case or whether the object is simply young enough to be that large. As given by the size limit for brown dwarfs objects can be this large. The additional information explaining this seems a bit hidden. Stevinger (talk) 10:19, 11 August 2024 (UTC)

This only works if luminosity and temperature values are representative of the object itself, which I highly doubt for objects such as Proplyd 133-353. These objects, as stated below, are surrounded by large amounts of gas and dust that significantly affect their thermal emission, therefore also affecting any size estimate for these objects and making them appear larger than feasibly possible. Unless the paper explicitly provides radius figures that address these concerns, this seems to me like providing a derived, potentially flawed figure and significantly overstating its confidence. ArkHyena (talk) 12:14, 11 August 2024 (UTC)

This is fine for me. Proplyd 133-353 might be heavily influenced. The problem here is that you generalize it to other objects! Let's take GQ Lupi b as example. One of the sources given called 'Characterizing the protolunar disk of the accreting companion GQ Lupi B'[9] gives the cited radius of 3.77 Jupiter radii. If you check the publication object and disk dominate different parts of the spectrum and both are fit together to the spectrum, in this case BT-Settl (models for the companion) + extinction + (modelled) disk leading to a radius of the companion (!) of 3.77 Jupiter radii. Two things are not correct here. 1) the disk does not 'affect any size estimate'. To be fair you write now here that the present exception is possible. The contributing scientists simply know and can calculate which part of the spectrum of which object is influenced by the thermal radiation you mention and 2) 'making them appear larger than feasibly possible'. None of the objects in the list is larger than feasibly possible. Any hot Jupiter is below the Hot Jupiter limit. Any other object is below the Brown dwarf limit and a general planet limit is not given (yet). Stevinger (talk) 13:50, 11 August 2024 (UTC)

If you want to remove objects with reference radius measurements, you would need to provide reasons for this for objects individually. (I write this because you wrote: 'This, at the very least, requires a big caveat on this influence, if not excluding these objects entirely.'). Marking which reference takes it into account for which object would be great, but would be a lot of work and the question is whether it is realibly given then.

I did not want to say you do not know all this, which I assume from your sentence starting with 'Unless the paper explicitly provides radius figures that address these concerns ...', but I emphasize it here for other readers, since I stated below that there is a new trend of removing objects with limited information given as reason, e.g. because other objects were removed. Stevinger (talk) 14:09, 11 August 2024 (UTC)

Those measurements for objects such as GQ Lupi b are still modelled, which may be subject to caveats. GQ Lupi b's sources even state as much:

Based on the companion's Lbol from Stolker et al. 2021, we estimate m = 33 ± 10 MJup and r = 3.7 ± 0.7 RJup for GQ Lup b.

(Xuan et al. 2024)

The use of GQ Lup b’s Teff from ForMoSA as input for the ATMO evolutionary tracks predict a mass of, a radius in the range of 2.65 −= 3.3 RJup...

(Demars et al. 2023)

With these values, we derive a luminosity of log(L/L�) = −2.25 ± 0.24, slightly higher than in (Neuhäuser et al. 2005), but consistent within the error margin. From luminosity and temperature, we can then estimate the radius of the companion to be R = 3.50+1.50 −1.03 RJup.

(Seifahrt et al. 2007)

Now, estimated/modelled radii alone have nothing inherently wrong per se, but this list combines them with exoplanets who've had their radii directly measured via methods such as transit—which could reasonably be expected to be significantly more accurate than radii modelled from luminosity. I am no expert in exoplanetary astronomy, but I would, perhaps naively, expect modelling to also vary in conclusion depending on methodology and input parameters used, especially since these models do not seem to have any established baseline to calibrate these models against—as far as I can tell, we have never directly measured the radius of a protoplanet. Indeed, Seifahrt et al. 2007 appears to use an older luminosity figure for GQ Lup b, and accordingly arrives to a different, conflicting estimated radius than Xuan et al. 2024. All this considered, at least a major caveat ought to be given for transparency's sake, no? ArkHyena (talk) 21:56, 12 August 2024 (UTC)

To the final part, there are multiple potential ways this could be addressed by changing the format of the list to better accommodate the inherently greater uncertainties some radii figures have, including explaining the aforementioned caveats in the (currently unsourced) Limitations section. Total removal would be the more extreme option—and one I would still support—but if others insist on keeping these objects in the list, then so be it. ArkHyena (talk) 22:05, 12 August 2024 (UTC)

Please see my additions to the discussion below. From this point of view and the strong similarities to the List of largest stars your suggestion for total removal of a full group of objects does not only seem to be a more extreme option, but a pretty extreme one. Stevinger (talk) 09:24, 13 August 2024 (UTC)

There you got some pretty bad examples, I have to give you that. But it is again a mixup. The first two values from Xuan and Demars I wouldn't trust too much. Indeed they use evolutionary models, either putting in Lbol or Teff using a best age estimate (!) to find a most likely mass and radius. This can work, but is as you write gradually worse calibrated the younger and lower mass the object is. This is why they write estimate or predict. The third example is different, this is why I added it back after it was removed recently. Seifahrt et al. determine the temperature from atmospheric fitting, so spectral retrieval of the temperature. Then they use luminosity and temperature to derive the radius via the Stefan–Boltzmann law. You could use a blackbody to fit the spectrum, but atmospheric models include known deviations from the blackbody, why they are preferred for accuracy reasons. Seifahrt et al. likely wrote 'estimate', because at the time in 2007 the distance to the host star, a major ingredient in the luminosity was not well measured and they did kind of educated guessing it would be as far away as the average of other Lupus star-forming region members. This is now measured with the GAIA satellite and was measured before from the ground. I assume you had a typo when you mention the conflicting estimated radii of Xuan et al. 2024 and Seifahrt et al. 2007, because they are almost identical. If you meant Demars, than you should be able to find, that in addition to the 2.65 - 3.3 Rjup, Demars also have atmospheric radii, being about 4.07 - 4.45 Rjup, consistent with all the other values. Indeed the only conflicting are the 'predicted' ones. How good the educated guessing was by Seifahrt et al. 2007 you can see from the detail that 14 years later Stolker et al. 2021 arrive at almost the same radius of 3.77 RJup, despite having a much more precise distance, and modelling both the then known disk and the object simultaneously. The object and others have large uncertainties, but the radii seem to be all around 3.5 - 4.5 Jupiter radii, even most 'predicted ones', showing that most evolutionary models are not too far off. Stevinger (talk) 08:35, 13 August 2024 (UTC)

Thank you for the idea to have additional reference objects. True, we don't have good radii of protoplanets. However,, there is the eclipsing binary brown dwarfs at 1 Myr V2384 Orionis, @21.Andromedae mentions below, which are kind of proto brown dwarfs at this age. I added them as reference objects, showing very young brown dwarfs are huge. Hopefully similar measurements will be available for planets in the future. Stevinger (talk) 08:44, 13 August 2024 (UTC)

As @Nrco0e phrased it: 'Forgive me for being overly pedantic': You write radii of transiting planets are measured directly. Technically one measures the reduced or scaled radius (Rp/Rstar), and the reduced or scaled semi-major axis (a/Rstar) and the period. Via Kepler's laws of planetary motion you can connect the semi-major axis and the period of the object to get a stellar radius from the measured (a/Rstar). However, Kepler's third law includes the star's mass Mstar. This mass is either calculated from its radius or empirical models are used, ... long story short, this is technically also not a full direct measurement. I assume you are interested if that matters. Usually not, stars are usually well known, so the planet radius is very well determined, in accuracy and precision. However, there are at least two examples in this list for which it matters. 1) KOI-13b (Kepler-13 Ab) has radii from 1.512±0.035 RJ to 2.216±0.087 RJ to 2.63+1.04−0.82 RJ. It could be one of the largest planets. The reason is that a single publication gives these three values because the primary star is not clearly defined in mass and radius in the literature. A fourth value is even determined in another publication: 2.03 RJ by mostly members of the Kepler satellite team. While the values are individually very precise, but at least one of the two values 1.512±0.035 RJ and 2.216±0.087 RJ is inaccurate, we don't know clearly which. Still it clearly belongs into the list in my opinion. 2) Pollera (WASP-79b) has radii 1.70±0.11 – 2.09±0.14 because it cannot be determined whether the host star is on the main-sequence or not. The difference in the properties of the host star again change the result of the planet. Stevinger (talk) 09:03, 13 August 2024 (UTC)

So the good directly measured transiting radii rely on stellar mass and Kepler's third law and the good direct imaging radii rely on measured distance, effective temperature from spectra and the Stefan-Boltzmann law. For the latter luminosity (needing distance) and temperature (from spectroscopy or other sources) are used to derive the radius. I mention this again since in the List of largest stars this L/T_eff method is used for every star outside the Milky way and even if you include the Milky Way stars it is used for the vast majority of objects, including the largest case. I do not see, why this should not work for exoplanets. Please see my suggestion below to possibly also include a method column in the present list. Stevinger (talk) 09:16, 13 August 2024 (UTC)

Proplyd 133-353 is still likely to be large, it is literally only 500 thousand years old and already 13 times more massive than Jupiter. Very young objects tend to be larger, V2384 Orionis for example is 0.69 R_☉ in size, but 0.057 M_☉ in mass, because it is only 1 million years old. Even Jupiter was larger at its formation. The planet's luminosity is still decreasing, if Proplyd 133-353 were 1 Myr old it would have a luminosity of 0.00307 L_☉ and hence a radius of 2.99 R_J. 21 Andromedae (talk) 13:58, 11 August 2024 (UTC)

Yes, I'm not disputing that young objects are almost all likely to be large. However, that alone is not enough to clear the inclusion of any young object regardless of sourcing or how its radius was determined without at least a disclaimer. ArkHyena (talk) 21:37, 12 August 2024 (UTC)

I understand if you want to remove CFHTWIR-Oph 90, CFHTWIR-Oph 98 and KPNO-Tau-4, because so far only evolutionary model radii are given or from a source that is sourcing another publication 'submitted' in the table. Their values are, however not very exceptional and they are free-floating. Please see the discussion above. Stevinger (talk) 08:38, 13 August 2024 (UTC)

Indeed a disk that is oriented to block emission from the point of view of Earth could make the object appear to be less luminous. In this case the object might be more massive and uninteresting for this list. If, however, not in the line of sight from Earth it would barely have an influence, the object could be a very high-mass planetary mass free-floating object and according to the reference and graphs therein be younger than 500000 years, because it formed as a second-generation object there. As given by @21.Andromedae above a 1 Myr object already has about 3 Jupiter radii, a 500000 years one or even younger would be much larger. If you wonder, the formation times of collapsing objects are usually regarded to be several thousand years. So, I hope that you discuss this on the basis of whether candidates should be included or not in this list.

The color also clearly marks it as free-floating, in order to clarify, that the IAU working group on extrasolar planets would not regard it as a planet, but as ' "sub-brown dwarfs" (or whatever name is most appropriate).' Stevinger (talk) 20:06, 12 August 2024 (UTC)

Multiple issues

Following a recent series of edits, I believe there are multiple issues with this list that need to be addressed.

1. The usage of artists' depictions for exoplanets in this list is unusual and, in my opinion, unwarranted. There was indeed an earlier discussion about this topic, but this discussion only had three participants—two of whom failed to make any reasonable justification as to why such images should be kept. This cannot reasonably be regarded as consensus in favor of keeping these illustrations. Though WP:ASTROART hasn't any specific guidelines for lists, I believe this excerpt applies: When choosing images to illustrate astronomical objects, editors should select images with maximum potential to inform readers and minimum potential to misinform readers. At best, these illustrations serve no meaningful, much less encyclopedic purpose—this is a list about exoplanet sizes, after all. At worst, several of these illustrations are blatantly misinformative: the TrES-2b illustration depicts exomoons where none have been confirmed. This is an issue that is only exacerbated seeing as actual imagery is thrown into the mix.
2. Related to the issue regarding Proplyd 133-353, many of the entries in this list are extremely young (< 20 Myr) objects surrounded by dust and gas, including GJ Lup b, OTS 44, and DH Tauri. These objects are surrounded by large amounts of gas and dust that significantly affect their thermal emission, therefore also affecting any size estimate for these objects and making them appear larger than feasibly possible. This, at the very least, requires a big caveat on this influence, if not excluding these objects entirely.
3. Several entries are also accompanied by additional information. Most simply include mass and other basic information, but several that I had removed before they were reinstated contain significant amounts of trivial information. Major sourcing/prose issues aside, what warrants the inclusion of material such as the ambiguous a very puffy hot Jupiter, The tidally-locked planet where winds move 18,000 km/h, and where molten iron rains from the sky due to daytime temperatures exceeding 2,400 °C (4,350 °F), or This planet is so close to its parent star that its tidal forces are distorting it into an egg-like shape.? I understand including information for planets that represent significant milestones or have additional exceptional properties, but beyond those this feels uncomfortably close to MOS:MISC.

ArkHyena (talk) 20:21, 10 August 2024 (UTC)

Additionally, it should probably be pointed out that this list is not unique in having some pretty significant issues in quality, consistency, etc. Several astronomy lists are in quite bad shape, with Parejkoj making this pretty damning statement: To the question of whether astronomers are, or should be, using Wikipedia as a data source: I mostly hope that they do not. We have our own curated sources for data values (e.g. NED, SIMBAD, or the SDSS value added catalogs), and it's almost always not as simple as just grabbing the "top" value from a catalog. This often happens on Wikipedia, and results in long arguments by non-experts about e.g. which star is biggest. I've tried at various points to get colleagues to edit wiki pages when they notice something incorrect without much success; you don't get tenure or grant funding editing wiki! (from this active RFC). In my opinion, it is clear to me that we need much stricter controls on quality and accuracy for these lists, especially since these lists are—for better or for worse—very hot topics in pop astronomy. ArkHyena (talk) 07:22, 11 August 2024 (UTC)

I was actually unsure how to phrase my discomfort with the current situation. But I decided to not post a much more angry version of this reply. Instead of using the existing topics a new topic was created, which is fine to emphasize the topic I assume. But then a tag was put to the main page stating that the factual accuracy of the article is disputed, which gives a very bad impression to anyone reading it, while it seems no one cared about the open, previously raised topics for month. The first two points raised were previous topics, I am not saying not relevant or that the things aren't in need of changes, but the third point raised is so far not connected to factual accuracy, but rather whether part of the information given is miscellaneous. Stevinger (talk) 13:30, 11 August 2024 (UTC)

Just because previous topics garnered little or no attention doesn't mean said topics do not warrant attention. I agree with the placement of the Dispute tag—at least four people here are actively questioning the accuracy of several elements in this list, myself included. This seems to be in line with WP:DISPUTED procedure. Point three indeed doesn't concern accuracy, so I've removed it from the Dispute tag. ArkHyena (talk) 13:58, 11 August 2024 (UTC)

@21.Andromedae, Stevinger, APerosn53248, and Foxy Husky: You were all actively editing the list at the same time during August 2024. Would you all mind to explain and address these concerns? Nrco0e (talk • contribs) 20:24, 10 August 2024 (UTC)

To clarify ArkHyena's point about surrounding dust around young objects, I'd like to mention that HD 100546 b suffers the same problem as GQ Lup b, DH Tau b, etc. with surrounding dust making them appear brighter than they really are. I don't see a reason why just HD 100546 b is excluded from the list, but not those objects. Nrco0e (talk • contribs) 20:31, 10 August 2024 (UTC)

Also pinging @SpaceImplorerExplorerImplorer since you have extensive involvement with superlative lists. What are your thoughts on these concerns? Superlative lists like this tend to be highly popular to the general public, so quality control is important. I believe that including appropriate caveats like surrounding dust is equally as important as having accurate size estimates in this list here. Nrco0e (talk • contribs) 20:53, 10 August 2024 (UTC)

For the "artist's depictions", I do think they should be removed. They often take descriptions of these exoplanets literally, like with WASP-12 b and Kepler-1 b, which are both described as being "pitch black", despite their stellar irradiance and thermal emission which make those planets appear incredibly bright.

For the additional comment, I do agree that these lists need to be stricter to retain accuracy due to many entries of these lists coming from catalogues with automated calculations and many assumptions that fit most of whatever type of object is being researched. Especially with lists like the list of largest stars, which includes a large portion of an entire catalogue. SpaceImplorerExplorerImplorer 11:42, 11 August 2024 (UTC)

@SpaceImplorerExplorerImplorer Out of curiosity, what specific measures, if any, would you say is needed to help these lists become more reliable and consistent? Additionally, what are your thoughts on initiating a Peer Review for this (and similar)? Would they be beneficial? ArkHyena (talk) 21:57, 12 August 2024 (UTC)

These lists shouldn't contain any entries that only have data for whatever value in automated catalogues and/or that use idealisations that can make them drastically differ. Lists of astronomical extremes should only or at least mostly contain estimates that have been carefully constrained rather than contain loads of estimates that have been calculated using the exact same methodology.

And the measures to keep it that way should be by reviewing every source to keep consistency.

Initiating a peer review process doesn't sound like a bad idea therefore and could actually be very useful if possible. SpaceImplorerExplorerImplorer 22:21, 12 August 2024 (UTC)

Thank you for your input! I'll probably initiate a peer review sometime down the line, then :)

For the first part, I do not know how acquiring consensus would work—I would be reluctant to initiate an RfC for that matter. ArkHyena (talk) 22:24, 12 August 2024 (UTC)

The existence of HD 100546 b is disputed. 21 Andromedae (talk) 21:18, 10 August 2024 (UTC)

I'd like to mention that at least GQ Lup b and DH Tau b don't suffer the same problem as HD 100546 b, not just because they aren't disputed. Both objects are expected to be as large as given here, being fully consistent with evolutionary models at their age. I am in this regard a bit worried if mentioned as 'making them appear larger than feasibly possible'. The reason very young objects are this large is that they are born large and contract within their lifetime, till they are as large as expected for objects at the age of the Sun. If you have a massive planet at, e.g. age 500000 years it could be larger than 3 Jupiter radii. Still, embedded planets are difficult. Their determined radius can be very off if the additional material is not taken into account.

To me a partly connected recent trend is an issue. While it is fine to remove objects if not relevant for the list, recently objects are removed with a simple note to consensus, mass or radius or because other objects were removed. I would like to give the example of DH Tau b (not removed in this case). It is currently the best candidate for being the largest exoplanet, however, in its discovery publication it was determined to have 30 - 50 Jupiter masses, which changed a lot. Removal should be explained shortly. If the majority has a different opinion, I will get used to it. Stevinger (talk) 07:35, 11 August 2024 (UTC)

I was of course partly incorrect by saying 'till they are as large as expected for objects at the age of the Sun'. Please see the following graph, if you are interested from Burrows 1997.[10] In red are planets, in green brown dwarfs and in blue stars. All objects reduce their luminosity with age. This happens by cooling and contracting, changing temperature and size. I was incorrect, because the graph shows, that even Jupiter and other small objects keep contracting at the age of the Sun.

This graph naturally explains why the youngest objects (< 20 Myr) are at the top of this list, since they are on the left of the graph. If you want to remove the youngest objects from this list, you remove all the objects that have the potential to be larger than the given Hot Jupiter size limit. This seems to make a List of largest exoplanets pointless. Stevinger (talk) 09:29, 11 August 2024 (UTC)

I'd like to add that the methods producing the large radii of e.g. GQ Lupi b and OTS 44 also produce the low radii of HR 8799 b, c, d, e and especially Beta Pictoris b. Beta Pictoris b is a very good comparison, because a edge-on disk around Beta Pictoris (being larger than 1000 AU in total) is superimposed on the companion's position. Nevertheless the radius is < 1.5 Jupiter radii. You can argue that this is a gas free dusty debris disk, but nevertheless DH Tau b is 0.5 - few million years old, expected to be larger than 2 Jupiter radii, Beta Pictoris b is > 20 million years old and expected to be < 2 Jupiter radii. Stevinger (talk) 20:38, 12 August 2024 (UTC)

not that much concerns... i just add note for UY Scuti for initial report of radius and also make the references on WOH 604 radius easier to read Foxy Husky (talk) 17:18, 11 August 2024 (UTC)

besides... editing the table with preview on side make my laptop lag really bad so i forced to edit one by one Foxy Husky (talk) 17:22, 11 August 2024 (UTC)

Strongly support removing the image column from this and other lists, but the main editors of these lists are going to disagree. SevenSpheres (talk) 20:25, 10 August 2024 (UTC)

I strongly oppose the removal of artistic illustrations, they are interesting, useful, illustrate the article and, contrary to what has been said, they are informative in nature. Take WASP-12b as an example, the text says that "This planet is so close to its parent star that its tidal forces are distorting it into an egg-like shape. As of September 2017, it has been described as "black as asphalt", and as a "pitch black" hot Jupiter as it absorbs 94% of the starlight that reaches its surface." and the artistical illustration show this. This list will probably be seen by laypeople and the illustrations make the these large planets better understood. 21 Andromedae (talk) 21:12, 10 August 2024 (UTC)

That information is irrelevant to the planet's size and belongs in the article on the planet itself. Please also consider the fact that artist impressions do not necessarily "make planets better understood"; they can also misinform readers, for example by giving the false impression that a hot Jupiter would appear pitch black to the eye, or that we know more about a planet's size and composition than we really do. SevenSpheres (talk) 21:25, 10 August 2024 (UTC)

If an artistic illustration is misleading, remove it. It is a list of the largest exoplanets, but may also contain additional information. The list of nearest stars, for example, contains information about the constellations, masses, coordinates, and so on, of the nearest stars, even when these things are loosely related to the list's scope. 21 Andromedae (talk) 22:05, 10 August 2024 (UTC)

Regarding that particular example, I would disagree. Mass and spectral type are pretty fundamental parameters for a star, and coordinates, constellation, parallax, and magnitude are basic astronomical parameters that are relevant to a list about astronomical objects sorted by distance. By contrast, that list does not include an artists' depiction of each entry for the sake of illustration. This is more akin to how this list (if somewhat inconsistently) includes information about an object's mass and probable type, not depictions based upon our loose knowledge of what each object may look like. ArkHyena (talk) 06:48, 11 August 2024 (UTC)

I see the arguments of both sides, but I have to add, that 'an egg-like shape' is relevant for the size of an object. If I am an interested reader of the list and had never heard of an object, it would feel wrong to learn about this fact only if I click on the individual article of a specific planet. Stevinger (talk) 07:44, 11 August 2024 (UTC)

Also 'hot Jupiter' with a link is relevant, since it explains to the reader, how an object of 0.34 Jupiter masses can be twice as large as Jupiter. Stevinger (talk) 09:08, 11 August 2024 (UTC)

@21.Andromedae: Forgive me for being overly pedantic and playing devil's advocate here, but would WASP-12b really appear "pitch black" when it's so close to its star?

At its distance from its star, WASP-12b receives 1.04×10⁷ W/m² ≈ I = L_star/4πa_orbit² of starlight, using WASP-12b's orbital radius and star luminosity from their Wikipedia infoboxes. Given WASP-12b's radius, it receives 6.04×10²³ W = I·A_WASP12b of starlight on its star-facing hemisphere (assume a circular surface area A_WASP12b = πR_WASP12b² for WASP-12b's single hemisphere, due to it being tidally locked). Since WASP-12b reflects 8.6% of the total light it receives (from the latest geometric albedo measurement in 2024, which isn't in the Wikipedia page), multiplying the planet's geometric albedo with the starlight received in Watts tells us that WASP-12b is reflecting approximately 5.19×10²² W of light from its star-facing hemisphere. The total reflected starlight from WASP-12b is almost 29 million times brighter (in Watts) than Earth's Moon, which reflects 1.81×10¹⁵ W of the Sun's light and appears bright to us on Earth! (for a solar irradiance of 1361 W/m², aka the solar constant, and Moon geometric albedo of 0.14). Furthermore, WASP-12b has an equilibrium temperature of 3000 K (from the latest paper on this), which is hot enough that it would visibly glow red over its entire surface. Assuming WASP-12b is a blackbody with emissivity of 0.9, it would emit roughly 680000 W/m² of 700 nm (red) light, corresponding to a luminosity of 1.6×10²³ W when multiplied by WASP-12b's spherical surface area. The thermal emission luminosity is roughly 4.1 times higher than the amount of starlight WASP-12b reflects! (Blackbody calculations here)

Therefore, the pop media claim of "pitch black" hot Jupiters is nothing more that a terrible misunderstanding of albedo vs. flux/light intensity. This is why I personally am skeptical of pop media portrayals of planets and other astronomical bodies. Nrco0e (talk • contribs) 23:27, 10 August 2024 (UTC)

If you want a more accurate illustration of WASP-12b, this image is the way to go. File:WASP-12b a Hot, Carbon-Rich Planet.jpg Nrco0e (talk • contribs) 23:27, 10 August 2024 (UTC)

First things first: I love the calculations. However, the topic is difficult. I think it is usually referred to as dynamic range, being important here. Please never directly look at the Sun, but if you have protective equipment, you can see that Sun spots appear, e.g. 'pitch black' to the eye. Nevertheless, they are usually a bit hotter than the 3000 K, brighter than the Moon if they could be looked at isolated, and the Sun as star is less luminous than Wasp-12. In my opinion it is simply the question, how much sway or tolerance you give to an artist's impression. It should, however, be clear it is one, and not being a direct imaging observation. Stevinger (talk) 07:05, 11 August 2024 (UTC)

I agree that the artists depictions should all be removed from this list. People generally look at that kind of thing and think "that's what the planet looks like", and then are confused when you tell them that we have no pictures of exoplanet surfaces. Your other points sound similar to the problems with the "list of largest galaxies" page that was deleted some years ago: it was a grab bag of objects with completely inconsistently determined sizes, many of which weren't galaxies at all (e.g. a galaxy with very large radio lobes). Unless you start with a clear definition of how you're measuring planet size and/or how you're cross-calibrating different kinds of measurement, you're going to have a mess. - Parejkoj (talk) 18:05, 12 August 2024 (UTC)

That is not necessarialy so, removing all illustrations will not make people stop that these are the planets' real pictures. That's why the column with the images is named "illustration". Until now no solid arguments were made for removing these pictures. 21 Andromedae (talk) 18:22, 12 August 2024 (UTC)

Conversely, I have yet to see any solid arguments for keeping these images. I recognize that these illustrations sit in quite the gray area, and beyond WP:ASTROART covering depictions in broad strokes there is no specific policy for these images. Thus, whether or not to keep them hinges on whether or not their impacts are more useful than not—and more editors here seem to believe that they are not. ArkHyena (talk) 22:20, 12 August 2024 (UTC)

Originally I preferred slightly to remove the images. But since the possibly most misleading were already removed I tend to keeping them. The moving planets around HR 8799 are impressive. The image of PDS 70 c shows you that you might want to check for PDS 70 b, too, since you see there are two of them. The image of Beta Pictoris b shows you there is a huge edge-on disk, the image of OTS 44 shows you it has a disk on its own, ... Please see my suggestion to give a second key for illustrations below. In this way people might be shown here why not to confuse artist's depictions with real direct images, possibly bringing a useful impact. I am not sure if people reacted yet, who are in favor of keeping the images, see e.g. Parjkoj below, since the discussion was so far mostly why to remove them. If I am wrong and the border style idea is disliked, please follow the majority. Stevinger (talk) 08:05, 13 August 2024 (UTC)

21 Andromedae, I don't understand this statement: "removing all illustrations will not make people stop [believing?] that these are the planets' real pictures." If we don't show artists illustrations, people won't see them and thus won't even know to think that they are real images of the planets. We have a mix of actual astronomical imaging (which I think we absolutely *should* include), images showing relative size vs. Jupiter (given some of the error bars, that seems like a stretch in some cases), and some very fanciful artists renditions that may have no relation to what the planet looks like. Remember, we've *never* imaged the surface of an exoplanet, so any such image is based on unverified models, at best, and often is mostly just fabrication. Example: the picture for WASP-121b shows the sun-facing surface as "white hot", which is ridiculous, it's only 2500ºC. - Parejkoj (talk) 05:48, 13 August 2024 (UTC)

People know these images. Either from news articles, other media or individual wiki pages. I have a wild suggestion: On the wiki help Help:Table I found that you can use Border styles. There is also the possibility to give a second key/legend with different border colors and give e.g. artist's depictions a red border, size comparison images a blue border and direct images actually taken a green border, maybe even a fourth color for direct images which are a composite of several instrument observations, as the case for PDS 70 c? In this way everybody is given the additional information that these types of illustrations should not be confused with each other (no matter with how much previous knowledge you arrive at the page). Stevinger (talk) 07:55, 13 August 2024 (UTC)

Fortunately people ar not adding objects confusing the orbital separation of transiting planets with their size or even the protoplanetary disk size of direct imaging planets' hosts, being several astronomical units. From what you are saying it might be a good idea to add a 'Method' column, like the case in the List of largest stars. Defining the method seems very good, explaining how it works seems beyond what a list is supposed to do. Stevinger (talk) 20:26, 12 August 2024 (UTC)