An international team of researchers used the James Webb Telescope to study the atmosphere of the L 98-59 d super-Earth. They were able to find sulfur compounds indicating violent volcanic activity.
Super-Earth near a red dwarf
L 98-59 d is one of four confirmed exoplanets orbiting a red dwarf 34.6 light-years from Earth. It represents a super-Earth. L 98-59 d has a mass 1.52 times and a radius 1.94 times the mass and radius of Earth. It completes one orbit around its star in 7.5 days. The equilibrium surface temperature of L 98-59 d is 143 °C, placing it well outside the habitable zone.
Based on an average density of L 98-59 d, researchers have suggested that this is an aquatic world with water and/or water ice accounting for a significant portion of its mass. However, the results of observations made with the James Webb Telescope (JWST) present a very different picture. L 98-59 d may be a volcanic, rather than a watery, world.
The fact is that L 98-59 d is a transiting exoplanet. Every time it passes in the background of its star, part of the starlight passes through its atmosphere. JWST was able to isolate this light and obtain its spectrum. Next, an international team of researchers used computer models based on available data on exoplanet atmospheres to build a potential understanding of the chemical composition of the L 98-59 d gas shell.
Ocean of magma?
The results surprised the scientists. They were unable to find traces of carbon dioxide or water vapor. Instead, the exoplanet’s atmosphere was rich in sulfur dioxide (SO₂) and hydrogen sulfide (H₂S). Their presence indicates violent volcanic activity similar to what we see on Jupiter’s moon Io. It may be provoked by the proximity of L 98-59 d to its star, as well as by tidal interactions with neighboring planets that stretch its interior, melting it and causing violent eruptions. Scientists even admit that the surface of L 98-59 d may be covered by an ocean of magma.
If the discovery is confirmed, L 98-59 d would be the smallest exoplanet with an atmosphere ever found. Although this world is hardly home to life for obvious reasons, it allows scientists to better understand exactly how exoplanets form. Therefore, they intend to continue studying it.
Earlier we reported on which of our nearest exoplanets could be targets for an interstellar expedition in the future.
Provided by Phys.org
