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TRAPPIST-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.

Article milestones Date Process Result January 22, 2022 Peer review Reviewed June 14, 2022 Featured article candidate Not promoted July 25, 2022 Peer review Reviewed October 28, 2022 Featured article candidate Not promoted March 15, 2023 Good article nominee Listed September 3, 2023 Featured article candidate Promoted 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)? 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

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This article has been viewed enough times in a single week to appear in the Top 25 Report. The week in which this happened: February 19 to 25, 2017 (10th) On 23 February 2017, TRAPPIST-1 was linked indirectly from Google, a high-traffic website. ( Traffic) All prior and subsequent edits to the article are noted in its revision history. Daily pageviews of this article A graph should have been displayed here but graphs are temporarily disabled. Until they are enabled again, visit the interactive graph at pageviews.wmcloud.org Text and/or other creative content from this version of 2MUCD 12171 was copied or moved into TRAPPIST-1 with this edit on 16 November 2021. The former page's history now serves to provide attribution for that content in the latter page, and it must not be deleted as long as the latter page exists. Section sizes Section size for TRAPPIST-1 (35 sections) Section name Byte count Section total (Top) 7,977 7,977 Discovery 3,582 3,582 Description 4,203 7,937 Rotation period and age 1,173 1,173 Activity 2,561 2,561 Planetary system 3,205 25,374 Size and composition 2,740 2,740 Resonance and tides 6,308 6,308 Skies and impact of stellar light 2,146 2,146 Habitable zone 3,843 3,843 Moons 1,258 1,258 Magnetic effects 1,302 1,302 Formation history 4,572 4,572 List of planets 282 15,099 TRAPPIST-1b 2,027 2,027 TRAPPIST-1c 1,815 1,815 TRAPPIST-1d 1,596 1,596 TRAPPIST-1e 1,648 1,648 TRAPPIST-1f 1,229 1,229 TRAPPIST-1g 1,117 1,117 TRAPPIST-1h 1,141 1,141 Data table 4,244 4,244 Potential planetary atmospheres 9,828 15,384 Stability 5,556 5,556 Possible life 5,140 5,140 Reception and scientific importance 185 6,634 Public reaction and cultural impact 2,620 2,620 Scientific importance 3,251 3,251 Exploration 578 578 See also 514 514 Notes 26 26 References 35 93,561 Sources 93,526 93,526 Further reading 1,518 1,518 External links 786 786 Total 183,532 183,532

The following references may be useful when improving this article in the future: Scholar News Edu and Gov

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

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

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

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

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

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

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

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

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