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<blockquote style="position: relative; padding-left: 55px;"><section><a href="https://astrodon.social/users/kellylepo/statuses/111048449661799507">Kelly Lepo (kellylepo@astrodon.social)'s status on Wednesday, 13-Sep-2023 01:41:58 JST</a><a href="https://astrodon.social/@kellylepo" title="kellylepo@astrodon.social"><img src="https://gnusocial.jp/avatar/28639-48-20221116180105.webp" width="48" height="48" alt="Kelly Lepo" style="position: absolute; left: 0; top: 0;">Kelly Lepo</a><div><a href="https://astrodon.social/@kellylepo/111048159929663838" rel="in-reply-to">in reply to</a></div></section><article><p>And now we move into the exoplanet part of the afternoon. </p><p>Results from Nikku Madhusudhan about exoplanet<br>K2-18 b. They have the first detection of methane and carbon dioxide in a habitable-zone exoplanet.</p><p>Press release: <a href="https://webbtelescope.org/contents/news-releases/2023/news-2023-139" rel="nofollow noreferrer">https://webbtelescope.org/contents/news-releases/2023/news-2023-139</a></p><p><a href="https://astrodon.social/tags/JWSTYearOne" rel="tag">#JWSTYearOne</a></p></article><footer><a rel="bookmark" href="https://gnusocial.jp/conversation/2052104#notice-4026653">In conversation</a><time datetime="2023-09-13T01:41:58+09:00" title="Wednesday, 13-Sep-2023 01:41:58 JST">about a year ago</time> <span>from <span><a href="https://astrodon.social/@kellylepo/111048449661799507" rel="external" title="Sent from astrodon.social via ActivityPub">astrodon.social</a></span></span><a href="https://astrodon.social/@kellylepo/111048449661799507">permalink</a><h4>Attachments</h4><ol><li><label><a rel="external" href="https://gnusocial.jp/attachment/1511982">The JWST Spectrum of K2-18b |
1. Motivation 
2. JWST Observations 
3. Atmospheric Retrieval 
4. Implications for K2-18 bK2-18 b  A Habitable-zone Sub-Neptune transiting a M2.5 V star 
P = 33 day, transit depth = 3% (Montet et al. 2015)
M_p=7.96 +/- 1.91 M_E (Cloutier et al. 2017) 
R=2.61+/- 0.08 R, (Benneke et al, 2019)
Teq = 250-300 K, Earth-like insolation
No analogue in the solar system.
Image Credits: NASA, ESA, CSA; NN</a></label><br><a href="https://cdn.masto.host/astrodonsocial/media_attachments/files/111/048/408/357/562/082/original/ada95689c65c9439.png" rel="external">https://cdn.masto.host/astrodonsocial/media_attachments/files/111/048/408/357/562/082/original/ada95689c65c9439.png</a></li><li><label><a rel="external" href="https://gnusocial.jp/attachment/1511983">Atmospheric Composition 
Graph of Transit depth (%) vs Wavelength (microns). Yellow and red datapoints on a blue a cyan model. Several Methane (CH4) bumps are labled. * H,-rich with high abundance (&gt;1%) of CH, and CO, 
* Non-detections of H,0, NH, and CO 
* Marginal evidence for DMS, potential biomarker
* Evidence for Clouds/Hazes and Low stratospheric temperatures Madhusudhan 2023</a></label><br><a href="https://cdn.masto.host/astrodonsocial/media_attachments/files/111/048/411/701/671/798/original/be77aaf1372f8312.png" rel="external">https://cdn.masto.host/astrodonsocial/media_attachments/files/111/048/411/701/671/798/original/be77aaf1372f8312.png</a></li><li><label><a rel="external" href="https://gnusocial.jp/attachment/1511984">Conclusions
* First detection of CH4, and CO2, in a habitable-zone exoplanet
— Resolution to missing methane problem in a temperate exoplanet * High CH4, and CO2, and Low NH3; consistent with Hycean world
— Composition inconsistent with mini-Neptune or rocky world
— New theoretical work needed for alternate explanations * Potential inference of DMS, possible biomarker molecule
— More modeling and observations needed for robustness
— New theoretical work needed to establish biological activity * Pathway to explore exoplanet habitability with JWST
— Hycean worlds to expand and accelerate the search for life</a></label><br><a href="https://cdn.masto.host/astrodonsocial/media_attachments/files/111/048/412/553/561/943/original/7b1463699f9f8dc3.png" rel="external">https://cdn.masto.host/astrodonsocial/media_attachments/files/111/048/412/553/561/943/original/7b1463699f9f8dc3.png</a></li><li><label><a rel="external" href="https://gnusocial.jp/attachment/1511985">Untitled attachment</a></label><br></li></ol></footer></blockquote>

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Kelly Lepo (kellylepo@astrodon.social)'s status on Wednesday, 13-Sep-2023 01:41:58 JST Kelly Lepo
in reply to
And now we move into the exoplanet part of the afternoon.
Results from Nikku Madhusudhan about exoplanet
K2-18 b. They have the first detection of methane and carbon dioxide in a habitable-zone exoplanet.
Press release: https://webbtelescope.org/contents/news-releases/2023/news-2023-139
#JWSTYearOne
In conversationabout a year ago from astrodon.socialpermalink
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