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Abolisyonista (abolisyonista@ni.hil.ist)'s status on Friday, 18-Apr-2025 15:44:50 JST Abolisyonista

Is anyone else stoked about the news coming out of K2-18b? It's a Hycean world where last year it was reported that dimethyl sulfide was discovered in its atmosphere, a chemical that is only produced by life on Earth. Just this week, scientists think there's more evidence for dimethyl sulfide on the planet.

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  Abolisyonista (abolisyonista@ni.hil.ist)'s status on Friday, 18-Apr-2025 15:47:45 JST Abolisyonista
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  http://arxiv.org/abs/2504.12267
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    New Constraints on DMS and DMDS in the Atmosphere of K2-18 b from JWST MIRI
    
    The sub-Neptune frontier has opened a new window into the rich diversity of planetary environments beyond the solar system. The possibility of hycean worlds, with planet-wide oceans and H$_2$-rich atmospheres, significantly expands and accelerates the search for habitable environments elsewhere. Recent JWST transmission spectroscopy of the candidate hycean world K2-18 b in the near-infrared led to the first detections of carbon-bearing molecules CH$_4$ and CO$_2$ in its atmosphere, with a composition consistent with predictions for hycean conditions. The observations also provided a tentative hint of dimethyl sulfide (DMS), a possible biosignature gas, but the inference was of low statistical significance. We report a mid-infrared transmission spectrum of K2-18 b obtained using the JWST MIRI LRS instrument in the ~6-12 $μ$m range. The spectrum shows distinct features and is inconsistent with a featureless spectrum at 3.4-$σ$ significance compared to our canonical model. We find that the spectrum cannot be explained by most molecules predicted for K2-18 b with the exception of DMS and dimethyl disulfide (DMDS), also a potential biosignature gas. We report new independent evidence for DMS and/or DMDS in the atmosphere at 3-$σ$ significance, with high abundance ($\gtrsim$10 ppmv) of at least one of the two molecules. More observations are needed to increase the robustness of the findings and resolve the degeneracy between DMS and DMDS. The results also highlight the need for additional experimental and theoretical work to determine accurate cross sections of important biosignature gases and identify potential abiotic sources. We discuss the implications of the present findings for the possibility of biological activity on K2-18 b.
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  Abolisyonista (abolisyonista@ni.hil.ist)'s status on Friday, 18-Apr-2025 15:48:27 JST Abolisyonista
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  - Che Boludo
  @Winstonwells You wouldn't want to live there. It's a hot soup world, even if there is life there.
  
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  Che Boludo (winstonwells@mastodon.social)'s status on Friday, 18-Apr-2025 15:48:28 JST Che Boludo
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  @abolisyonista I wonder what their immigration policy is
  
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  Abolisyonista (abolisyonista@ni.hil.ist)'s status on Friday, 18-Apr-2025 16:59:12 JST Abolisyonista
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  - levampyre
  @levampyre Can you link me? As far as I know, there isn't any major hypothesis yet for an abiotic explanation for DMS in K2-18b. Even the same scientists who made the discovery are waiting for major abiotic explanations for the exotic chemical processes for DMS on that world.
  
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  levampyre (levampyre@chaos.social)'s status on Friday, 18-Apr-2025 16:59:14 JST levampyre
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  @abolisyonista Wasn't there a post on anorganic synthesis of dimethyl sulfide here just two days ago. It started with "It's never aliens."
  
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  levampyre (levampyre@chaos.social)'s status on Friday, 18-Apr-2025 17:54:37 JST levampyre
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  @abolisyonista If I find the thread back I sure will. But a simple search didn't yield any quick results just yet. It is also completely possible that the thread wasn't about dimethyl sulfate and I'm mixing it up. I will be on the lookout.
  
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  Abolisyonista (abolisyonista@ni.hil.ist)'s status on Friday, 18-Apr-2025 17:56:57 JST Abolisyonista
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  - levampyre
  @levampyre Replicating abiotic synthesis of DMS and situating it in K2-18b would kinda be big news, not a series of tweets or toots.
  
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  Abolisyonista (abolisyonista@ni.hil.ist)'s status on Friday, 18-Apr-2025 17:59:11 JST Abolisyonista
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  - levampyre
  @levampyre Replicating abiotic synthesis of DMS and situating it in K2-18b would kinda be big news, not a series of tweets or toots.
  
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