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Illustration of the artist of exoplanet K2-18b. | Credit: NASA, ESA, CSA, Joseph Olmsted
Scientists have found further indications of possible biosign academic nuclear on the nearby exoplanet K2-18B, which strengthens the case that it could support foreign life.
In 2023, researchers who used the James Webb Space Telescope (JWST) from NASA reported on the potential presence of dimethylsulfide (DMS) on K2-18B, which is almost nine times more massive than earth and circles in the “habitable zone” of a star in about 120 light years.
Here on Earth, DMS is mainly produced by life – the most productive of Phytoplankton and other sea microbes – so that the study from 2023 met with a certain enthusiasm. However, the excitement was alleviated by the preliminary nature of the find; The observations of JWSt agreed with the presence of DMS, but they did not confirm. So the study team looked again, but this time something else.
JWST can examine exoplanet atmosphere if these worlds exceed “transit” or the face of your host stars from the perspective of the observatory: The telescope detects certain molecules in the air based on the wavelengths of the star light that absorb them.
Related: Hosted exoplanet K2-18b extraterrestrial life or not? Here is the reason why the debate continues
The team made the original, preliminary DMS detection using JWSTS NIRISS (Near-Infared Imager and slantless spectrograph) and nirspec instruments (near-infrared spectrographs). For the new study, the researchers used the mid-infrared instrument (Miri) of $ 10 billion, which examined various wavelengths of the light.
Miri also recognized the fingerprint of DMS (and/or dimethyldisulfide or DMDS, a tight chemical cousin and also a potential biosignature).
“This is an independent evidence in which a different instrument is used than before and another wavelength area in which the previous observations do not give overlap,” said Nikku Madhusudhan, professor at Cambridge University Institute of Astronomy, which was both K2-18B studies, in a current statement. “The signal came through strong and clear.”
Based on its size and other characteristics, the astronomers suspect that K2-18B could be a “Hycean” world-a class of exoplanet, which was proposed in 2021 and has a huge fluid water ocean and a hydrogen-rich atmosphere. (“Hycean” is a Portmanteau of “hydrogen” and “ocean”.)
According to the new study, the air of K2-18B is also rich in DMS and/or DMDS. The researchers appreciate the concentrations of more than 10 parts per million according to volume, compared to less than part of the billion for them here on earth.
“Earlier theoretical work had predicted that a high level of sulfur base such as DMS and DMDs in Hycean-Welten are possible,” said Madhusudhan. “And now we have observed it in accordance with what was predicted. In view of what we know about this planet, a Hycean world is with an ocean that is teeming with life, the scenario that best suits the data that we have.”
Related stories:
– Has the James Webb World Card telescope really found life beyond the earth? Scientists are not so sure
– The surface of exoplanets can be covered with oceans, says James Webb space telescope
-The water vapor on “habitable” exoplanet K2-18 B is exciting-but it is not a earth twin
Madhusudhan and his team do not claim to have discovered alien life; You say that more research is necessary to confirm and expand your results. Other scientists feel as much and some of them in the debate about K2-18B and their life organizer of heavier skepticism.
One of them is the astronomer Chris Lintott, who dealt with Madhusudhans “strong and clearer” characterization of the DMS/DMDS signals.
“In the meantime, the paper examined by experts says” [the presence of molecules] DMDS and DMS explain the current observations, their combined meaning … is at the lower end of robustness that is required for scientific evidence.
Recognizing signs of extraterrestrial life is a difficult business, and it is even more difficult to confirm it-especially in a world like K2-18b, which we cannot examine nearby for the foreseeable future. So we should expect the debate and data acquisition to be continued.
