Talk:TRAPPIST-1

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Featured articleTRAPPIST-1 is a featured article; it (or a previous version of it) has been identified as one of the best articles produced by the Wikipedia community. Even so, if you can update or improve it, please do so.
Main Page trophyThis article appeared on Wikipedia's Main Page as Today's featured article on May 17, 2025.
Did You KnowIn the news Article milestones
DateProcessResult
January 22, 2022Peer reviewReviewed
June 14, 2022Featured article candidateNot promoted
July 25, 2022Peer reviewReviewed
October 28, 2022Featured article candidateNot promoted
March 15, 2023Good article nomineeListed
September 3, 2023Featured article candidatePromoted
Did You Know A fact from this article appeared on Wikipedia's Main Page in the "Did you know?" column on April 28, 2023.
The text of the entry was: Did you know ... that the star TRAPPIST-1 has seven planets, several of which may have temperatures that would allow the existence of liquid water (artist's impression depicted)?
In the news A news item involving this article was featured on Wikipedia's Main Page in the "In the news" column on February 22, 2017.
Current status: Featured article


File:Possible Interiors of the TRAPPIST-1 Exoplanets.jpg

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File:Possible Interiors of the TRAPPIST-1 Exoplanets.jpg has been commented out for a while because it incorrectly claims that the density is precisely known. There is an alternative file File:Possible Interiors of the TRAPPIST-1 Exoplanets 02.png which however lacks all text. Jo-Jo Eumerus (talk) 18:23, 17 July 2023 (UTC)[reply]

"And As Such"

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I'm no expert, but, in the following sentence, the use of "and as such" makes what is an explanation or an elaboration sound like further speculation.

  • They are all likely tidally locked to TRAPPIST-1, and as such it is believed that each planet is in permanent day on one side and permanent night on the other.

I'd change it to

  • They are all likely tidally locked to TRAPPIST-1: each is believed to have permanent day and night sides.

Markup vs Template:Starbox begin

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The page currently does not use Template:Starbox begin b/c that template repeatedly links several pages, as per Nimbus227's comments at the featured article candidacy. However, the current markup is messy, probably will become a maintenance issue, and folks at Template talk:Starbox begin have said that they don't think it's highly important to avoid overlinking in the template also for reader reasons. Jo-Jo Eumerus (talk) 08:42, 15 August 2023 (UTC)[reply]

Table before or after planet sections?

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I am not convinced that putting the table after the planet sections is useful. For good or ill, the planet sections are just brief summaries and the table is the more important information. Jo-Jo Eumerus (talk) 07:11, 18 September 2023 (UTC)[reply]

I think that the orbital information should be placed last because this is not what the general reader looks for first. But that's just my opinion. CactiStaccingCrane (talk) 16:17, 19 September 2023 (UTC)[reply]
Good job with the explanatory notes though! This is something IMO all FA articles about a technical topic should have. CactiStaccingCrane (talk) 16:19, 19 September 2023 (UTC)[reply]

Infobox breaks popups

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This edit by User:Jo-Jo Eumerus causes the popup to display the literal wikisource:

! style="background-color: #FFFFC0; text-align: center;" colspan="2"|

rather than the first sentence or so of the article itself. I assume it is due to the fact that the infobox header is in a template whereas this row of the table is directly in the article, and the light-weight popup doesn't do a full parsing/transclusion to recognize that it's a table. Did a {{Starbox character}} get subst:ed by accident? DMacks (talk) 15:22, 29 November 2023 (UTC)[reply]

It wasn't an accident, unfortunately - as noted on the FAC page the template overlinks and thus was deemed unacceptable. Jo-Jo Eumerus (talk) 15:23, 29 November 2023 (UTC)[reply]
Boo. Ok. Convenience links: FAC-discussion subtopic and Template talk:Starbox begin#How to make the template not overlink. DMacks (talk) 15:38, 29 November 2023 (UTC)[reply]

Where to mention JWST

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Currently, the first mention of the James Webb Space Telescope is in the TRAPPIST-1b section. I've put a second link in the scientific importance section since it's more important there, but I'd like to get second opinions on where to put the link and where the acronym - maybe one in the lead too? Jo-Jo Eumerus (talk) 08:26, 5 December 2023 (UTC)[reply]

Sentence on atmosphere

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I've added some information in the "potential atmospheres" section on the ruling-out of an atmosphere around TRAPPIST-1b but I don't really like it. Also, while anyone's here, can anyone check whether the nbsp bits need to be added anywhere? Jo-Jo Eumerus (talk) 12:07, 5 December 2023 (UTC)[reply]

Stellar obliquity

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Not sure if this source warrants an update. Jo-Jo Eumerus (talk) 09:05, 31 December 2023 (UTC)[reply]

Black hole mediated escape

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This source discusses the possibility that active phases of Sagittarius A* might remove hydrogen/oxygen atmospheres of the middle TRAPPIST-1 planets. Jo-Jo Eumerus (talk) 17:20, 27 January 2024 (UTC)[reply]

The percentage of potentially removed gasses from the atmospheres of these exoplanets is (according to that paper) in the order of 1e-14, much lower than the measurement accuracy of the mass of the planets in question. While it's certainly a possibility, I wouldn't worry about it. The influence of the star itself on atmospheric losses is much greater, because it's so much closer. Dhrm77 (talk) 01:49, 28 January 2024 (UTC)[reply]

JWST is inconclusive (currently) on the presence of atmosphere

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I'm aware of the two Nature articles published last year, but it is often omitted that these preliminary observations are single photometric measurements confined to a single bandpass, 13.5–16.6 μm. It is impossible to rule out presence of all thick atmospheres solely based on a single bandpass [1](p. 9). Yes the measurements rule out a large subset of CO2 atmospheres, but there still exist subset of CO2 atmosphere that can exhibit airless feature at 13.5–16.6 μm but may show up in other bandpasses. If we only have a single bandpass data, then presence of thick CO2 atmosphere cannot be ruled out, though the most parsimonious interpretation would be airless/thin atmosphere.

Indeed, more observations in a different bandpass 11.6–14.2 μm has found surprisingly low emission that is possibly indicative of heat redistribution by a thick atmosphere [2]. A type of thick atmosphere that show up in 11.6–14.2 μm wavelength, but not in 13.5–16.6 μm, is CO2 with thermal inversion.

Nothing conclusive about the presence of atmospheres on 1b and 1c until double phase curve or more bandpass measurements out, maybe later this year! Aleral Wei (talk) 18:45, 28 March 2024 (UTC)[reply]

Mmm, while I concur sorta, so as long as published sources don't say "actually, we can't rule out an atmosphere with this" or "actually, this isn't consistent with an airless planet" we can't say that on Wikipedia. Jo-Jo Eumerus (talk) 08:03, 29 March 2024 (UTC)[reply]
You're right, my comment mainly addresses the apparently contradictory conclusions reached by the two papers, [1] and [2]. The second paper, more comprehensively, analyzed two bandpasses 11.6–14.2 and 13.5–16.6 μm and concluded with possibly thick atmosphere on 1b only seen in 11.6–14.2 but not in 13.5–16.6 μm. I thought it would be more updated to include the 2nd paper's conclusion in the wikipedia. Aleral Wei (talk) 19:27, 29 March 2024 (UTC)[reply]
The second paper is a preprint that has not yet been accepted for publication. SevenSpheres (talk) 20:21, 29 March 2024 (UTC)[reply]
There is also this preprint which argues that no atmosphere should present around any of the planets, but it's a radiative cooling analysis and given this I think that neglecting the atomic line cooling is likely to make a grossly inaccurate analysis. Jo-Jo Eumerus (talk) 07:29, 8 April 2024 (UTC)[reply]
Observation >> numerical modeling in terms of evidence level. Given the rather clear absorption feature at 11.6–14.2 μm, I will be rather surprised if double phase curve confirms the planet airless. Sometimes I wonder if 11.6–14.2 μm was arranged to observe first before 13.5–16.6 μm, we are probably drowning in papers on how CO2 rich these planets are. But I'm in no hurry to edit anything, and don't plan to even after the 11.6–14.2 μm paper gets through peer review. I'm certainly expecting phase curve to confirm the existence of atmosphere, later this year or the next. Aleral Wei (talk) 01:09, 9 April 2024 (UTC)[reply]
An update, the paper that show JWST observation doesn't yet rule out CO2 with thermal inversion is accepted into Nature Astronomy https://arxiv.org/abs/2412.11627 Still waiting for GO3077 phase curve for more conclusive result Aleral Wei (talk) 04:36, 17 December 2024 (UTC)[reply]

Annual update

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Didn't include a few sources:

  • This one because of the discussion above regarding reliability. Granted, it's my analysis so it might be improper to exclude it for that reason.
  • A lot of sources discussing TRAPPIST-1e since they can be discussed at TRAPPIST-1e
  • Numerous sources about formation scenarios that aren't reviews. In particular on the first 10 or so pages of sources, e.g [1] and [2]. We really need some review articles to collate all the formation hypotheses.
  • I am not sure if this is supposed to be a book?
  • Not sure that this source can be interpreted as a hypothesis of past hydrogen atmospheres around the planets.
  • This might be a good review.
  • This is probably too local news-y to warrant mention.

Probably also need to check the Ducrot addition to the TRAPPIST-1c section, as I am not sure it is well-written.

As well as these abstracts which are erroring out: [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] Jo-Jo Eumerus (talk) 21:35, 28 December 2024 (UTC)[reply]

"from Earth they seem to move past the disk of the star"

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This sentence is confusing. I don't know what phenomenon is meant here, nor am I convinced that it adds something that hasn't already been said.

I may not be an astronomer, but one shouldn't have to be in order to understand a wikipedia article, right?

What is "the disk of the star"? Is that a general phenomenon? Does every star have one? It can't be the protoplanetary disk, because this star system is super old. Is it another kind of disk that I don't know about? Why doesn't our sun have a disk - maybe only red dwarfs?

And what does "moving past the disk" mean? Does that mean, instead of *through* the disk, said planets move *past* it? Why is this special or unexpected, or informative? It only adds to my confusion about this interesting star system... 131.174.18.214 (talk) 12:10, 18 March 2025 (UTC)[reply]

It just means we see the planets pass in front of the star; in other words, the planets transit the star. I see how that wording can be confusing; it should be rewritten. SevenSpheres (talk) 16:32, 18 March 2025 (UTC)[reply]

Airlessness

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Quote:

"Airlessness is possible,[229] but only if the surface is subject to rapid volcanic overprinting which is expected given the amount of tidal heating.[228] However, water vapour- or oxygen-rich atmospheres or no-atmosphere scenarios are possible."

What is "airlessness"? Different from "no-atmosphere"? No air? jnestorius(talk) 13:48, 17 May 2025 (UTC)[reply]

Yes. I am not sure why scientists say both airlessness and no-atmosphere, but I figure it's because even e.g Mercury and the Moon have an "atmosphere" of sorts. Jo-Jo Eumerus (talk) 07:15, 18 May 2025 (UTC)[reply]
That was not a yes/no question; I suggested two different possible responses. I don't know which, if either, is your "yes". jnestorius(talk) 13:02, 18 May 2025 (UTC)[reply]
As far as I know "airlessness" and "no-atmosphere" mean the same thing here, i.e. it is possible that the planet lacks an atmosphere. Looking at the source though, it does not seem to support the claim but only if the surface is subject to rapid volcanic overprinting which is expected given the amount of tidal heating; in fact it's mainly about planet b and barely discusses planet c. SevenSpheres (talk) 16:07, 18 May 2025 (UTC)[reply]
Even if some other source can be found for that claim, it is redundant at best to state both "[a]irlessness is possible" and "no-atmosphere scenarios are possible" if they mean the same thing. jnestorius(talk) 20:04, 18 May 2025 (UTC)[reply]
I moved this claim up to the TRAPPIST-1b section, since it is correct but only for that planet. Jo-Jo Eumerus (talk) 08:29, 20 May 2025 (UTC)[reply]

exoplanet

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The star Trappist-1 is not orbited by exoplanets. They are exoplanets only in relation to a star they do not orbit, such as Sol. Tsaalman (talk) 16:41, 17 May 2025 (UTC)[reply]

Changed something. Jo-Jo Eumerus (talk) 07:35, 18 May 2025 (UTC)[reply]

System's ecliptic?

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In: The inclinations of planetary orbits relative to the system's ecliptic are less than 0.1 degrees, how is system's ecliptic defined? in my understanding, the ecliptic is the orbital plane of the Earth (or of the planet from which one is observing). catslash (talk) 22:53, 18 May 2025 (UTC)[reply]

Should probably be phrased as "The inclinations of planetary orbits relative to each other". The sources don't use the term "ecliptic", either. SevenSpheres (talk) 23:11, 18 May 2025 (UTC)[reply]
Pretty sure one can define an ecliptic even for non-Sun planetary systems, by averaging over the orbits of bodies. I also remember that "The inclinations of planetary orbits relative to each other" was considered vague somewhere, but it might be me imagining things. Jo-Jo Eumerus (talk) 08:36, 20 May 2025 (UTC)[reply]

Erroneous source on data table temperatures

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https://en.wikipedia.org/wiki/TRAPPIST-1#Data_table

The temperature header in the data table cites Grimm et al. 2018, but I can't find any specific temperatures listed in that paper. That reference needs to be updated; maybe the values too, if a new source has to be identified. There are temperatures listed in Delrez et al. 2018, but they don't exactly match the ones in the table. Stephtdouglas (talk) 20:34, 8 August 2025 (UTC)[reply]

OK, I think I found the source. They are from Delrez et al. 2020, which is not currently cited anywhere on the wiki page that I can find. 3rd to last line in Table 1
https://ui.adsabs.harvard.edu/abs/2020A%26A...640A.112D/abstract Stephtdouglas (talk) 20:51, 8 August 2025 (UTC)[reply]
I've corrected the reference. SevenSpheres (talk) 21:07, 8 August 2025 (UTC)[reply]

New addition

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​ Aside from the WP:CITEVAR issue, is it possible to link to a more definitive source? We've had problems at K2-18b with folks adding press releases that turned out to be disputed later, and which turned the articles into WP:PROSELINEy messes with no coherent voice. Jo-Jo Eumerus (talk) 07:50, 14 August 2025 (UTC)[reply]

The article is here [47], pls check it, it seems to be a peer reviewed published study. And sorry for citevar, I often forget about it. Artem.G (talk) 08:04, 14 August 2025 (UTC)[reply]
Hmm, for some reason it didn't show. Perhaps swapping that source into the article instead of the press release would work. Or I might handle it myself when I do the yearly update. Jo-Jo Eumerus (talk) 09:49, 14 August 2025 (UTC)[reply]

TRAPPIST-1i candidate

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Yesterday, on 2 September, a preprint was submitted to arxiv (https://arxiv.org/abs/2509.02128v1) that mentions a possible detection of a ~Triton-sized exoplanet candidate around TRAPPIST-1 in a 2:3 resonance with TRAPPIST-1h. @SpaceImplorerExplorerImplorer then added TRAPPIST-1i to the table with the stated properties the authors gave. However, the authors also stated that:

Our posteriors closely matched our priors, and the BIC test significantly prefers the exclusion of the potential candidate with a BIC of 67. As a result, with the reduction and analysis methods described in this subsection, there is no clear evidence for the inclusion of a new transiting exoplanet.

To err on the more cautious side, especially considering that this article has not yet been published in a peer-reviewed journal the paper is accepted by Nature Astronomy and is pending publication, I've decided to remove TRAPPIST-1i from the table for now. I recognize that this could be controversial and it may still be beneficial to mention the candidate in some capacity though, especially if scicomm outlets pick up on this candidate. For now, that's not yet the case, but it could be worthwhile discussing how to mention the candidate in-article without overstating confidence in its existence. ArkHyena (she/they) 15:50, 3 September 2025 (UTC)[reply]

Yes, this should be mentioned in the text, in a section titled something like "search for additional planets", rather than (or at least in addition to) an entry in the planetbox table. The paper is already accepted for publication in Nature Astronomy. SevenSpheres (talk) 15:55, 3 September 2025 (UTC)[reply]
I support this move. This section could probably also be used to include other, previously proposed candidates, non-detections, and presumably including predictions (if there's not too many). AstroChara (talk) 16:22, 3 September 2025 (UTC)[reply]
There have been previous planet candidates? 21 Andromedae (talk) 16:36, 3 September 2025 (UTC)[reply]
There have previously been candidates for an eighth planet.
1) Very very recently, it was noted that planet h’s TTV deviate from the prediction of Agol et al. (2021) [48]. An eighth planet has been proposed to explain the additional perturbation [49].
2) Prior to this JWST study, the Spitzer detected several transit-like signals that do not correspond to any of the seven known planets, though none were strong enough to claim a detection [50]. Aleral Wei (talk) 02:32, 4 September 2025 (UTC)[reply]
The paper is published, and the planet meets the very definition of a 'candidate': There is no conclusive evidence for its existence. It does need to be in the table of planets, and to have its own section 'TRAPPIST-1 i' in the 'List of planets' section. 21 Andromedae (talk) 15:59, 3 September 2025 (UTC)[reply]
Is this paper published? I think we need to be sparing with using preprints as sources, per WP:PREPRINT. Jo-Jo Eumerus (talk) 10:05, 5 September 2025 (UTC)[reply]
The comments on the arXiv abstract page say if a paper is accepted for publication; in this case it is (if not actually published yet). SevenSpheres (talk) 15:47, 5 September 2025 (UTC)[reply]
I personally don't think the candidate planet i strong enough to be included in the lead section, isn't it?SoojinHD219134star (talk) 02:33, 6 September 2025 (UTC)[reply]
Yes. 21 Andromedae (talk) 11:28, 6 September 2025 (UTC)[reply]

The section on planetary atmosphere needs an update

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Or at least a new footnote should be added. A study published in 2024 (https://www.nature.com/articles/s41550-024-02428-z) for Trappist-1b and the article about TRAPPIST-1b itself both meaned that "while it's possible that the planet is a bare rock with no atmosphere, the potential presence of a hazy, CO2-rich atmosphere has not yet been ruled out".SoojinHD219134star (talk) 02:52, 6 September 2025 (UTC)[reply]

I thought this caveat was already noted? JoJo Eumerus mobile (main talk) 14:13, 6 September 2025 (UTC)[reply]