The Deep Supercritical Water Atmosphere of Ocean World L 98-59 d
Located approximately 34.6 light-years from Earth in the southern constellation Volans , L 98-59 d represents one of the most scientifically significant volatile-rich exoplanets ever identified within our local galactic neighborhood. Orbiting a bright M3V red dwarf star, this world was initially detected in 2019 by NASA’s Transiting Exoplanet Survey Satellite (TESS) and subsequently characterized through high-precision radial velocity measurements obtained by the European Southern Observatory’s ESPRESSO spectrograph mounted on the Very Large Telescope (VLT). Precise mass and radius measurements reveal a body that deviates fundamentally from the high-density iron-silicate composition of terrestrial planets, establishing L 98-59 d as a quintessential ocean world dominated by volatile compounds . With a radius of roughly 1.52 Earth radii and a mass of approximately 1.94 to 2.3 Earth masses, L 98-59 d yields a mean bulk density of roughly 3.3 grams per cubic centimeter. This density is...