An Entirely New Type Of Planet Just Discovered Is A Hellish Nightmare

by Aaron Leong — Tuesday, March 17, 2026, 10:04 AM EDT

A team of astronomers led by the University of Oxford has identified a new class of liquid planet, a world defined not by oceans of water, but by a global reservoir of molten magma thousands of miles deep and a volatile atmosphere.

The planet, designated L 98-59 d, is a super-Earth roughly 1.6 times the size of our own, orbiting a red dwarf star just 35 light-years away. While astronomers initially speculated the world could be a water-rich ocean world due to its low density, data from the James Webb Space Telescope (JWST) has revealed a much different reality. The planet’s atmosphere is thick with hydrogen sulfide, the gas responsible for the smell of rotten eggs, and lacks the water vapor signatures expected of a temperate marine world. Instead, the chemical fingerprint points to a mushy, molten state where the interior is so hot that silicate rocks exist as permanently churning fluid.

l98 59 system — *L 98-59 d is comparatively close to its host dwarf star at about 7.45 orbital days*

What makes L 98-59 d scientifically interesting is how it's able to retain an atmosphere. Typically, a planet this close to its host star (approximately 0.05 AU) would have its gases stripped away by intense X-ray radiation. However, the researchers, whose findings were published in Nature, suggest that the planet’s magma ocean acts as a storage tank. High-pressure interactions at the boundary between the atmosphere and the molten interior allow the planet to host vast quantities of sulfur and other volatiles deep within its belly, slowly releasing them over time to replenish the toxic atmosphere. This cycle creates a geochemical equilibrium that keeps the planet inflated with gas despite the solar onslaught.

The surface of this world is also quite the inferno, with temperatures reaching 3,500° F (1,900° C). It's possible that tidal forces from neighboring planets in the system trigger massive waves across the magma sea, creating a landscape of shifting, incandescent goo rather than solid ground. Dr. Harrison Nicholls, the study’s lead author, noted that the whole planet is of the planet is "like molasses. It’s likely that this planet’s core would also be molten.”

This discovery forces a re-evaluation of the habitable zone. After all, L 98-59 d sits within the traditional range where scientists once hoped to find life, but its molten nature and harsh atmosphere prove that orbital distance is only one part of the story. If magma worlds are as common as this data posits, many planets previously flagged as potential habitable might actually be toxic, uninviting furnaces.

Main photo credit: JPL/Goddard