Astronomers discover super-Earth with help from James Webb infrared space telescope L98-59d signs of a secondary atmosphere containing traces of sulfur. The exoplanet orbits the closest red dwarf to the Sun and has strong volcanic activity, according to researchers. exoplanet L98-59d — One of the most interesting planets discovered in the L98-59 star system. It is located in the Flying Pisces constellation, about 35 light-years from Earth, and its discovery was made possible as part of the TESS (Transiting Exoplanet Survey Satellite) mission. Astronomers classify L98-59d as a super-Earth because its size and mass are larger than Earth, but smaller than Neptune.

Stars are known to surround a bright M-class dwarf L98-59 — There are at least four planets orbiting, but it was the super-Earth that caught the attention of astronomers from the Science Space Telescope Institute (STScI) in Baltimore. The results of observations obtained with the NIRSpec and NIRISS instruments “James Webb” during the planet’s passage through the stellar disk on June 25, 2023, revealed that the planet’s atmosphere is rich in sulfur. The study has been accepted for publication in the journal Earth and Planetary Astrophysics.

L 98-59d orbits its host star very close to it, at about 0.05 AU (about 5% of the distance from Earth to the Sun), with a period of 7.5 days. This proximity makes the planet hot: its surface temperature can reach 143 °C. Given that little is known about L98-59d’s atmosphere, the observations were made as part of Cycle 1 of the James Webb Guaranteed Time Observations (GTO) program.

The results of spectroscopic studies have shown that the atmosphere of the super-Earth could be rich in sulfur compounds such as H2S (hydrogen sulfide) and SO2 (sulfur dioxide), with hydrogen and helium likely being background gases. This is an important discovery because the presence of sulfur could indicate volcanic activity on the planet. The new results also point to the presence of a secondary atmosphere that could have formed as a result of volcanism or other geological processes.

“The presence of sulfur dioxide in the atmospheres of exoplanets like L98-59d is suggestive of photochemical processes, and our ability to detect this evidence is important for testing various models of planet formation,” the astronomers wrote.

Therefore, further research into the atmosphere of a super-Earth will help scientists understand the processes occurring on other Earth-like planets, especially those that exist in extreme conditions.