An international team of astronomers discovered carbon-containing molecules on the potentially habitable exoplanet K2-18b on September 11th, using data from NASA’s James Webb Space Telescope (JWST).
Exoplanet K2-18b 8.6 times the size of Earth It’s an exoplanet, which means we can detect its dip in brightness as it passes over the face of its host star.
This is what an exoplanet looks like. It was first discovered in 2015 It was discovered by the Kepler Space Telescope during NASA’s K2 mission, and its existence was later confirmed by the Spitzer Space Telescope and Doppler velocity techniques.
Observed by the Hubble Space Telescope in early 2019 A planet orbiting a cool red dwarf star is in the habitable zone or Goldilocks ZoneTraces of a red dwarf star and water vapor have been found in its atmosphere.
Research results of exoplanet K2-18b
Previous observations by the Hubble Space Telescope have suggested that, if confirmed by future studies, the planet could be the only exoplanet with water in its atmosphere and temperatures sufficient to support liquid water on its rocky surface.
Liquid water could only exist if the planet turns out to be terrestrial, meaning it has a solid surface and atmosphere like Earth, rather than resembling a miniature version of Neptune — meaning it’s a gaseous exoplanet.
Recent observations by NASA’s JWST indicate the presence of carbon-containing molecules, including methane and carbon dioxide.
From this, K2-18b Hythean exoplanetThis means it is a planet with a hydrogen-rich atmosphere and a surface covered with water and oceans.
Current observations from the JWST reveal that methane and carbon dioxide are abundant, and ammonia is deficient.
Ammonia is produced naturally in the human body and in nature by the anaerobic decomposition of plants and animals and is toxic, so large amounts of ammonia are toxic to most life forms on Earth.
These observations therefore support the hypothesis that an ocean of water may exist beneath K2-18b’s hydrogen-rich atmosphere.
In these early Webb observations, Dimethyl sulfide (DMS).
On Earth, it is only produced by life; most of the DMS in Earth’s atmosphere is emitted by phytoplankton in marine environments, some of which contain bacteria and fungi that can produce DMS as a metabolic by-product.
On Earth, DMS plays a dual role by contributing to the sulfur cycle and influencing climate.
DMS is produced by marine phytoplankton and released into the atmosphere, where it is oxidized to sulfate particles.
These particles act as cloud condensation nuclei, influencing cloud formation and, consequently, climate regulation.
What do the experts say? Is there life on K2-18b?
Carbon-containing molecules are known to exist in K2-18b, It doesn’t necessarily mean the planet can support life. It’s also important to remember that the environmental conditions on the planet are unclear, but as Hubble observations suggest, it could be a harsh environment.
Large size Its radius is 2.6 times that of the Earth.The planet probably has a large mantle of high-pressure ice inside, like Neptune, but a thinner hydrogen-rich atmosphere and surface ocean.
The Hythean world is predicted to have oceans of water; The ocean may be too hot Being habitable or liquid.
“While this type of planet does not exist in our solar system, sub-Neptunian planets are the most common type of planet known to date in our galaxy,” he said. “We have obtained the most detailed spectrum ever of the sub-Neptunian habitable zone, which allows us to resolve the molecules present in its atmosphere.”
Subhajit Sarkar, a team member from Cardiff University, explains:
The research team aims to conduct follow-up surveys to further verify their findings and provide new insights into the environmental conditions on K2-18b.
The Webb Space Telescope’s next round of observations will use the telescope’s mid-infrared spectrometer to thoroughly survey K2-18b’s atmosphere, looking for chemical signatures called biomarkers, including DMS, that may indicate the presence of biological activity.
“Our ultimate goal is to discover life on a habitable exoplanet, which would transform our understanding of our place in the universe,” he said. “Our findings are a promising step in this direction.”
Nik Madhusudhan, an astronomer at the University of Cambridge and lead author of the paper announcing the results.
