Overview
- The peer-reviewed analysis combines 2024 James Webb Space Telescope spectroscopy with ground-based observations and nearly five billion years of planetary evolution modeling.
- Spectra show hydrogen sulfide and other sulfur compounds in L 98-59 d’s atmosphere, with JWST also detecting sulfur dioxide at high altitudes.
- Models indicate a global molten silicate mantle forming a deep magma ocean that stores sulfur and exchanges it with the atmosphere over geologic timescales.
- L 98-59 d is about 1.6 times Earth’s radius, sits roughly 35 light-years away, and has a low bulk density that does not match standard small-planet categories.
- Lead author Harrison Nicholls says such molten worlds are unlikely to be habitable and notes ESA’s Ariel and PLATO missions could assess how common they are.