Webb detects interesting molecular signals in a possible aquatic world

The Webb Space Telescope recently turned its focus to a nearby exoplanet and found that it may be a Hessian world, or a world covered entirely by a single global ocean, and with it Hydrogen atmosphere. What’s more, the telescope has made a potential discovery – note, maybe Detection of dimethyl sulfide, a molecule known to be produced on Earth only by living organisms.

The exoplanet is K2-18 b, a world approaching nine Many times the size of Earth, it orbits a star about 120 light-years away from Earth. Webb did You notice signs of water vapor On exoplanets before, but no exoplanet appeared to be covered in water oceans.

Webb – which was launched in December 2021 and has been collecting scientific data about the universe since July 2022 – was unable to discover the exoplanet; He was It was first spotted in 2015 By NASA’s K2 mission.

K2-18 b is located in the habitable zone around its star, meaning the world is at a distance from its star that is necessary for liquid water to persist on the exoplanet’s surface. Since water is essential to life as we know it, it is the primary obstacle for exoplanets to satisfy our current sensibilities regarding what is meant by HDrinkable. Another obstacle is the exoplanet’s temperature. It is possible that K2-18 b It is too hot for any of its oceans to support life, or even be liquid, according to NASA launch.

in it Reference nodal survey Regarding astronomy and astrophysics, the National Academies of Sciences, Engineering, and Medicine have emphasized the importance of finding habitable worlds. Webb is an important part of this research NASA has already made plans for Webb’s still-young successor to this research: Habitable Worlds Observatory. But that mission won’t launch for at least a decade, leaving Webb (and the Hubble Space Telescope, Webb’s still-operating predecessor) to do much of the exoplanet research.

Hubble Note the recently spotted exoplanet Back in 2019 it found evidence that the planet’s atmosphere contains water vapor. Webb’s notes go further. The Near-Infrared Imager, Non-Slit Spectrograph (NIRISS) and Near-Infrared Spectrograph (NIRSpec) captured the spectra of K2-18 b, by seeing how much starlight was blocked in the exoplanet’s atmosphere as it passed in front of its star.

Webb discovered the presence of carbon-bearing molecules such as methane and carbon dioxide, but little ammonia, on the planet. This chemical composition suggests that K2-18 b may have a water ocean beneath its hydrogen atmosphere. Analyze the candidate Hycean world Hosted on the arXiv preprint server It is accepted for publication in Astrophysical Journal Letters.

“Our findings underscore the importance of considering diverse habitable environments when searching for life elsewhere,” Niku Madhusudan, an astronomer at the University of Cambridge and lead author of the study, said in a NASA statement. “Traditionally, the search for life on exoplanets has focused primarily on smaller, rocky planets, but larger Hessian worlds are more suitable for atmospheric observations.”

Webb also discovered what looked like dimethyl sulfide (DMS) in the planet’s atmosphere. On Earth, dimethyl sulfide is produced by living organisms, and most of the DMS in our planet’s atmosphere is produced by marine phytoplankton. “Upcoming Webb observations should be able to confirm whether DMS is indeed present in the atmosphere of K2-18 b at significant levels,” Madhusudan added.

Madhusudan added that the data collected by Webb in just two observations of K2-18 b is equivalent to eight observations made by Hubble, thanks to the sensitivity of the newer space observatory and the range of wavelengths it observes.

Follow-up observations of the Hycean candidate will be made using the Webb mid-infrared instrument, or MIRI. While the discovery of dimethyl sulfide is very tentative, K2-18 b is increasingly showing signs of being a water world with potential – if not for astrobiological reasons, then for better understanding the types of habitable worlds in our own near-by universe.

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