Scientists have provided tentative evidence for a sulphur-rich atmosphere on the exoplanet L 98-59 d, located 35 light years from Earth. If confirmed, this would make it the smallest known exoplanet with an atmosphere.
L 98-59 d, discovered in 2019 by NASA's TESS space telescope, is classified as a super-Earth, approximately 1.5 times the size of Earth. The atmosphere may contain sulphur dioxide (SO₂) and hydrogen sulphide (H₂S), suggesting a molten or volcanic surface.
The research team utilized the James Webb Space Telescope (JWST) to observe a transit of L 98-59 d across its host star. This method, known as transmission spectroscopy, allows scientists to infer atmospheric composition by analyzing how starlight is altered as it passes through the planet's atmosphere.
Current models indicate that the absence of common gases like carbon dioxide, alongside the presence of sulphur gases, points to unique atmospheric processes distinct from those in our solar system. The extreme conditions on L 98-59 d may stem from tidal heating, akin to the volcanic activity on Jupiter's moon Io.
With a year lasting only 7.5 Earth days due to its proximity to its star, L 98-59 d experiences potentially hellish temperatures. Future JWST observations will be crucial to confirm the presence of the suggested gases and to deepen our understanding of such extreme worlds.
This discovery not only enhances our knowledge of exoplanet atmospheres but also contributes to the broader understanding of planetary evolution across the galaxy.