Astronomers discover what may be a new type of planet

The planet's environment would make it unlikely to sustain life.

March 16, 2026, 3:27 PM

Astronomers may have discovered a new type of planet beyond our solar system, according to new research.

The exoplanet, named "L 98-59 d," was first identified in 2019, but further observations using high-powered telescopes have allowed scientists to get a better understanding of its climate.

Researchers now know that L 98-59 d has some unusual characteristics. It is covered in oceans made of magma and has an atmosphere made of sulfur, according to a paper published Monday in Nature Astronomy.

It is a rocky planet, with a radius about 1.63 times larger and mass about 1.64 times that of Earth's, according to NASA.

An artist's impression of the exoplanet named L 98-59 d, shown with a cutaway to reveal its interior, orbiting a red dwarf star, with two of its sibling planets, seen in this image released on March 16, 2026.
Mark A. Garlick via Reuters

L 98-59 d's makeup is inconsistent with origin scenarios astronomers have previously described for planets of its size. In a gas-dwarf scenario, planets are believed to form rock cores that accrete a small percentage of hydrogen-helium during the formation process. In the water-world scenario, the planets contain a significant amount of liquid or frozen water.

The new exoplanet displays neither. Its mantle is likely composed of molten silicate rock, and its atmospheric makeup is indicative of substantial early sulfur and hydrogen content, in which it has evolved to host a "volatile-rich atmosphere," according to the researchers.

This would make L 98-59 d, which is 35 light years away from Earth, an unlikely environment to sustain life.

The exoplanet's atmosphere contains gases like water, sulfur dioxide and hydrogen sulfide -- which can smell like rotten eggs, especially when burned.

L 98-59 d was detected by the James Webb Telescope, the most powerful telescope ever put into space. Since 2021, the telescope has made several stunning discoveries as it orbits the sun, including several exoplanets that were previously not visible to astronomers.

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