SubNeptune planet K2-18b shows methane and dimethyl sulfide

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SubNeptune planet 120ly away shows presence of molecules associated with life
"A new investigation with NASA’s James Webb Space Telescope into K2-18 b, an exoplanet 8.6 times as massive as Earth, has revealed the presence of carbon-bearing molecules including methane and carbon dioxide.
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The abundance of methane and carbon dioxide, and shortage of ammonia, support the hypothesis that there may be a water ocean underneath a hydrogen-rich atmosphere in K2-18 b. These initial Webb observations also provided a possible detection of a molecule called dimethyl sulfide (DMS). On Earth, this is only produced by life. The bulk of the DMS in Earth’s atmosphere is emitted from phytoplankton in marine environments."

https://www.nasa.gov/goddard/2023/webb-discovers-methane-carbon-dioxide-in-atmosphere-of-k2-18b
 
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Very thrilling and exciting! :smile:
 
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Raises an eyebrow, a la Mr. Spock. "Fascinating!"Seriously though, do we have enough data on the exoplanet's mass, it's host star's mass and their separation to know whether K2-18b is tidally locked?

From popular science articles I've read (Sky & Telescope, I think) tidal locking is a problem for exoplanets orbiting red dwarves because these systems tend to be far more compact than our, more extended retinue of planets.

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

Several of the planets in the Trappist-1 system are expected to be tidally locked and I note that the outermost has an orbital period of 18.772 days. The cited period for K2-18b is 32.940 days. I wonder if that's sufficiently distant to place it outside of the tidal locking zone?

Any thoughts?Thank you,

Cerenkov.
 
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Stinky.
 
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FAQ: SubNeptune planet K2-18b shows methane and dimethyl sulfide

What is K2-18b?

K2-18b is an exoplanet located about 124 light-years away from Earth in the constellation Leo. It is classified as a sub-Neptune, meaning it is smaller than Neptune but larger than Earth, and it orbits within the habitable zone of its star, where conditions might be right for liquid water to exist.

Why is the presence of methane on K2-18b significant?

The presence of methane in the atmosphere of K2-18b is significant because methane can be a biosignature gas, indicating potential biological activity. However, methane can also be produced through non-biological processes, so its presence alone does not confirm life.

What is dimethyl sulfide, and why is it important in the context of K2-18b?

Dimethyl sulfide (DMS) is a molecule that, on Earth, is primarily produced by biological processes, particularly by marine phytoplankton. The detection of DMS on K2-18b is intriguing because it could suggest the presence of biological activity, though further investigation is needed to rule out non-biological sources.

How were methane and dimethyl sulfide detected on K2-18b?

Methane and dimethyl sulfide were detected on K2-18b using spectroscopic analysis of the planet's atmosphere. This involves studying the light from the planet's host star as it passes through the planet's atmosphere, revealing the chemical composition based on the absorption features in the spectrum.

What are the implications of these findings for the search for extraterrestrial life?

The detection of methane and dimethyl sulfide on K2-18b has significant implications for the search for extraterrestrial life. While these molecules are not definitive proof of life, their presence suggests that the planet has complex chemical processes that could potentially support life. This makes K2-18b a key target for future observations and studies in the ongoing search for habitable worlds beyond our solar system.

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