Scientists Propose New Exoplanet Class for 1.6-Earth-Size L 98-59 d
Updated
Updated · Scientific American · May 11
Scientists Propose New Exoplanet Class for 1.6-Earth-Size L 98-59 d
4 articles · Updated · Scientific American · May 11
L 98-59 d appears to be the first known member of a proposed new exoplanet class: a sulfur-rich, molten world with a mushy magma ocean rather than a standard rocky or ocean-planet profile.
1,500C surface heat, unusually low density and an atmosphere rich in hydrogen sulfide and sulfur dioxide drove that conclusion after data from TESS, Hubble and Webb failed to fit existing categories.
Computer models suggest the 5-billion-year-old planet could have formed from a volatile-rich disk, producing a body molten from surface to core and implying similar “sulfur worlds” may be common.
More than 6,000 exoplanets are now known, but researchers say L 98-59 d highlights how current labels are too narrow; another year or two of observations could confirm the planet’s makeup and expand a broader classification system.
What secrets about Earth's own fiery, volcanic past could this 'hellish' alien sulfur world finally unlock?
As telescopes find planets that defy theory, what fundamental rule of planet formation will be the next to break?
L 98-59 d and the Rise of Molten Planets: How a Sulfur-Rich World Is Transforming Exoplanet Science
Overview
The discovery of L 98-59 d, a newly identified molten planet, is reshaping how astronomers classify small exoplanets. As the prototype for a distinct class, L 98-59 d challenges the current, often oversimplified categories and reveals a much greater diversity of worlds beyond our Solar System. Its extreme conditions make it unlikely to support life, but its unique features are profoundly important for planetary science. This finding highlights the vast array of planetary types still awaiting discovery and underscores the need for more nuanced classification systems to better understand the universe.