Astronomers Identify Potential New Planetary Class Featuring Molten Interiors and Sulfurous Atmospheres

Researchers have proposed that exoplanet L98-59d may represent a previously unrecognized category of celestial bodies. A study published in Nature Astronomy on March 16 details this world, which possesses a molten rock interior and an atmosphere containing hydrogen sulfide, producing a distinctive odor. The planet, approximately 1.6 times Earth's size, was first reported in 2019 and observed with the James Webb Space Telescope. Its characteristics do not align with established classifications like gas dwarfs or water worlds. Scientists from the University of Oxford conducted simulations suggesting a long-lasting global magma ocean could sustain its atmospheric chemistry. While not habitable, the discovery highlights planetary diversity beyond our solar system.