Overview
- Published in Nature Astronomy on March 16, the analysis finds L 98-59 d—about 1.6 times Earth’s radius—has a bulk density near 40% of Earth’s while orbiting a nearby red dwarf 34–35 light-years away.
- JWST and ground-based observations reveal hydrogen sulfide and sulfur dioxide in a hydrogen-rich envelope, with ultraviolet light driving sulfur chemistry high in the atmosphere.
- Simulations reconstruct nearly five billion years of evolution, indicating a global magma ocean thousands of kilometers deep that stores vast sulfur reservoirs and helps retain the atmosphere despite stellar X-ray loss.
- The team reports surface temperatures exceeding roughly 1,500°C and a relatively small core, with the molten layer spanning about 70–90% of the interior radius, rendering the world inhospitable to life as we know it.
- Researchers propose L 98-59 d may be the first recognized member of a broader population of sulfurous magma-ocean worlds and call for follow-up with JWST, ESA’s Ariel, and PLATO to assess their prevalence.