Overview
- L 98-59 d orbits a nearby red dwarf about 35 light-years away and is roughly 1.6 times Earth’s radius with an unusually low bulk density for its size.
- JWST observations in 2024 detected sulfur-bearing gases including sulfur dioxide and hydrogen sulfide high in the atmosphere, consistent with ultraviolet-driven chemistry.
- Coupled interior–atmosphere simulations indicate a global magma ocean thousands of kilometers deep that stores and recycles large amounts of sulfur over billions of years.
- The molten interior likely helps the planet retain a thick hydrogen-rich envelope against X-ray-driven atmospheric escape, rendering the environment unlikely to be habitable.
- Researchers present L 98-59 d as a candidate first example of a wider population of sulfurous magma-ocean planets and highlight follow-up opportunities with JWST and ESA’s Ariel and PLATO.