K2-18b: new evidence on the possibility of life on the ocean

Dołączył: 11 Mar 2024 Posty: 1

A look from the James Webb Space Telescope ( JWST ) at exoplanet K2-18b revealed the presence of carbon, methane and carbon dioxide molecules on the surface. The discovery provides new information that supports the hypothesis that this body, located 120 light years away, could have a hydrogen-rich atmosphere and warm oceans.

K2-18b is an exoplanet discovered in 2015 that is located in the habit Phone Number List able zone of a white dwarf in the constellation Leo. It is approximately 2.7 times the size of Earth. In 2018, the Hubble space telescope detected signs of the presence of water vapor on the exoplanet. Since then, astronomers and astrobiologists have studied it carefully.

Signs of life on K2-18b
Thanks to the sophisticated observation instruments used, more and more astronomers assure that K2-18b is an oceanic planet (also categorized as hycean). If someone could travel there, they would probably find a warm, aquatic place with a dense atmosphere and optimal conditions for habitability.

In the most recent analysis of the body, JWST also detected traces of dimethyl sulfide , a compound found naturally on Earth. According to information provided by NASA, this type of sulfur can only be produced by life and, on our planet, it is generally produced by phytoplankton in marine environments.

For some astrobiologists, extraterrestrial life might not be found on rocky planets , but on those covered in liquid water with dense atmospheres. K2-18b is the closest exoplanet to be classified as oceanic . Its attractive characteristics, such as the abundance of methane and CO2, the scarcity of ammonia, its size and its relative proximity to Earth, make it one of the main objects of research when it comes to identifying habitable worlds or those with the possibility of hosting microorganisms. .

Artist's representation of what the PDS 70 system looks like.
James Webb detected water vapor in a protoplanetary disk
The water vapor is located in the inner disk of the PDS 70 planetary system, located 370 light years from Earth.
K2-18b, a planet eclipsed by the brightness of its mother
The main challenge in studying K2-18b is its parent star. The light from the white dwarf it orbits affects the receivers of space telescopes, making detailed study of the exoplanet's atmosphere difficult. To overcome this obstacle, researchers analyze the star's light and its dimming as it passes through K2-18b's dense atmosphere during its transit phase, that is, when it is between the star and the telescope.

The range and precision of the James Webb Space Telescope have made it possible to refine information about the planet's composition without making as many observations. According to Nikku Madhusudhan, lead author of the new exoplanet report, one JWST glimpse is equivalent to about eight Hubble observations over several years. For the last analysis, two transits of K2-18b (two complete revolutions around its star) were recorded.

The team responsible for the article published in The Astrophysical Journal affirms that it will continue to record the transits of the sub-Neptunian planet. With future JWST analyses, it is hoped to obtain a more precise understanding of the composition of K2-18b, which will contribute to the search for habitable worlds with the potential to host life.

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