The James Webb Space Telescope has discovered a potential ocean and carbon-containing molecules on a distant exoplanet. Heading towards this distant world which could have some surprises in store for us.
Discovered in 2015 by the Kepler telescope, K2-18b is an exoplanet 120 light years from Earth. Described as a mini-Neptune, this star has the particularity of being in the habitable zone of its star, a red dwarf located in the constellation Leo. We have known since 2019 that the atmosphere of this distant planet was rich in hydrogen thanks to measurements taken by the Hubble space telescope, but astonishing new information on the environment of this world has just reached us.
This time, it was the James Webb telescope which turned its instruments towards this star and discovered the presence of methane and carbon dioxide as well as the absence of ammonia. These elements are all clues to the existence of an ocean hidden under the planet’s atmosphere. The icing on the cake is that scientists believe they have detected traces of dimethyl sulfate, a molecule which on Earth is only produced by living organisms. Enough to arouse the curiosity of researchers looking for signs of life in the Universe.
While these findings are promising, they do not allow conclusions to be drawn. On the one hand, the presence of organic molecules is not yet confirmed and does not prove the existence of a form of life on the planet. This molecule could be the product of a reaction not involving any living being. On the other hand, it is far from certain that this exoplanet is habitable. Indeed, the ocean that covers the surface of this world could be far too hot to support life. Its temperature could even be too high for the water to remain in a liquid state.
To find out more about this mysterious planet, the James Webb telescope will have to carry out in-depth studies using its cutting-edge equipment. In particular, it should use its MIRI instrument capable of observing in the infrared and analyzing the composition of the atmosphere of K2-18b.
