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	K2-18b has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.
Article milestones Date Process Result April 5, 2023 Good article nominee Not listed June 29, 2023 Good article nominee Listed
	A news item involving this article was featured on Wikipedia's Main Page in the "In the news" column on September 13, 2019.
Current status: Good article

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So, it's that season when I usually update Wikipedia articles. Except that for this one, I wonder if there are objections to including all the publications here. I'd be also inclined to trim the "Discovery and research history" section a bit, as it stands it reads like a back-and-forth. Jo-Jo Eumerus (talk) 13:12, 1 November 2025 (UTC)[reply]

No objections from me, a yearly article update is a great thing! I also agree that trimming is a good idea: for example the whole paragraph about a podcast can be simply removed, while other stuff (in year x, in year y) should be trimmed. Artem.G (talk) 21:17, 2 November 2025 (UTC)[reply]

To be honest, I think the last paragraph in the lead also needs a heavy rewrite under WP:UNDUE - Ethan Siegel is far from the only researcher to have raised doubts, and "lab experiments that can produce DMS without life" is far from the only objection. Never mind that lab experiments showing that DMS can be produced abiotically do not actually imply that DMS in K2-18b's atmosphere can be explained that way; one would have to consider whether the quantities are plausible, for instance. Jo-Jo Eumerus (talk) 07:58, 6 November 2025 (UTC)[reply]

Agree, and at least two sources (5 and 7) are used only in lead. Artem.G (talk) 12:45, 6 November 2025 (UTC)[reply]

OK, rewrote the lead and tentatively also deleted the four paragraphs discussed below - WP:NOTCHANGELOG is about software updates, but I think we can extend that logic to research updates on an exoplanet too. Jo-Jo Eumerus (talk) 08:47, 7 November 2025 (UTC)[reply]

I suggest otherwise, a policy intended to be used on a specific context can't be applied to a different (and somewhat unrelated) context. Reporting research updates on an exoplanet is what we naturally do in Wikipedia. By the way, i think that the deleted paragraphs should be reinstated. 21 Andromedae (talk) 18:26, 7 November 2025 (UTC)[reply]

Research updates are fine, but why they're needed once they are outdated? And one of the paragraphs removed is A podcast on the Planetary Society's website in January 2024 featured NASA astrophysicist Knicole Colón describing some of the scientific results from the observations of K2-18b by JWST. This podcast episode is not notable by itself, and adds nothing useful, so why reinstate it? Artem.G (talk) 18:56, 7 November 2025 (UTC)[reply]

That and WP:PROSELINE is a bad style that also lends itself to giving WP:UNDUE weight to each specific study or press release. JoJo Eumerus mobile (main talk) 06:40, 8 November 2025 (UTC)[reply]

The thing that I wonder about though is whether astronomy articles enjoy an exemption from Wikipedia:Reliable sources#Preprints - "A study in 2025 with JWST using four new transit observations suggested that while K2-18b might have a water-rich interior, the tentative presence of DMS and methyl mercaptan (CH3SH) can be explained abiotically." for example is a preprint, and I don't think that New Scientist mentioning them on its own is enough to make that concern go away. Jo-Jo Eumerus (talk) 08:05, 6 November 2025 (UTC)[reply]

OK, I did the update. Somewhat predictably, the non-DMS aspects of K2-18b had fallen by the wayside. I'd like to remove the last 4 paragraphs of the discovery section (now the biosignatures section) since they are mostly highlighting particular studies and researchers (sometimes preprints) without combining everything into a coherent text. Also, as pointed out by Albergaria et al 2025 and Tennyson & Yurchenko 2025 the news and press releases probably aren't particularly reliable on this topic. Jo-Jo Eumerus (talk) 10:35, 6 November 2025 (UTC)[reply]

I have some concerns about JohannesBuchner's addition. One, it's based on a preprint and my understanding was that we frown on using them as sources. Two, the article now says "and high enough that cooling processes from CO2 are insufficient to retain an atmosphere" which a) doesn't appear to match what the source says - that K2-18's X-ray output is low - and b) a planet with K2-18b's size parameters being atmosphereless strikes me as a bit WP:EXTRAORDINARY. Jo-Jo Eumerus (talk) 09:47, 13 December 2025 (UTC)[reply]

Hi Jo-Jo Eumerus, I agree with you on the WP:PREPRINT issue that is a bit early, feel free to remove it. The first statement is supported by Figure 9, if the measured point were in the blue area the atmosphere could be retained (in the assumed model, if course). Figure 7 shows that the X-ray output for this star is quite low. ~2026-28557-9 (talk) 11:08, 14 January 2026 (UTC)[reply]

OK, removed it then. Jo-Jo Eumerus (talk) 12:15, 14 January 2026 (UTC)[reply]

This one might be worth adding. Or it may be just one model's opinion. Jo-Jo Eumerus (talk) 14:16, 7 January 2026 (UTC)[reply]

Did it anyway, albeit only a brief mention. Jo-Jo Eumerus (talk) 17:07, 30 January 2026 (UTC)[reply]