New form of searing, molten super-Earth exoplanet revealed

• L 98-59 d is a super-Earth exoplanet about 35 light-years from Earth. Scientists thought it was seemingly volcanically energetic resulting from its sulfur ambiance.
• The planet has a deep, world ocean of magma beneath its mantle, a brand new examine of information from the James Webb Space Telescope suggests.
• It represents a brand new kind of super-Earth planet not identified earlier than. It is probably going simply considered one of many such worlds in our galaxy.

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A molten super-Earth exoplanet 35 light-years away

An excellent-Earth exoplanet about 35 light-years away is not like any others seen earlier than. Researchers from Europe said on March 16, 2026, that the planet – L 98-59 d – represents a brand new class of rocky molten planet. The mantle is probably going molten silicate, much like lava on Earth. And beneath it’s a deep world ocean of magma. Scientists suppose the magma ocean extends for hundreds of miles beneath the mantle.

The University of Oxford within the U.Okay. led the examine, primarily based on new observations by the James Webb Space Telescope. Researchers from the University of Groningen, the University of Leeds and ETH Zurich had been additionally concerned.

L 98-59 d is about 1.6 occasions the diameter of Earth, making it a super-Earth kind exoplanet. But the planet’s unusually low density puzzled scientists. Its ambiance additionally comprises giant quantities of hydrogen sulfide. Being largely molten on the within may clarify each of those observations. The planet orbits a purple dwarf star. Red dwarfs are smaller and dimmer than our solar.

A earlier examine from 2024 had additionally hinted that L 98-59 d may be a volcanic exoplanet. Researchers had tentatively discovered the gases sulfur dioxide (SO2) and hydrogen sulfide (H2S) in its ambiance.

The journal Nature Astronomy published the brand new peer-reviewed findings on March 16, 2026.

Harrison Nicholls and colleagues counsel that exoplanet L 98-59 d may very well be totally composed of molten lava: a magma ocean masking a mushy core. [email protected]

— Nature Astronomy (@natastron.nature.com) 2026-03-16T17:41:18Z

A subsurface world ocean of magma

Why was the planet’s density so low for its measurement? The researchers used knowledge from latest observations of L 98-59 d and superior laptop simulations to search out the reply. They had been in a position to simulate the planet’s geological historical past throughout its practically 5-billion-year lifetime. This supplied clues as to what the planet is like on the within. What the researchers discovered was stunning.

The mantle is probably going molten silicate. That’s much like lava on Earth. But not like Earth, the examine outcomes counsel that beneath the mantle, there’s a world ocean of magma. That ocean is estimated to increase for hundreds of miles deep into the planet’s inside.

Part of a broader inhabitants

The researchers say that L 98-59 d may be simply considered one of many such worlds. It’s simply the primary one which astronomers have discovered. The researchers characterize them as “gas-rich sulfurous planets with long-lived magma oceans.” Lead writer Harrison Nicholls on the University of Oxford said:

This discovery means that the classes astronomers at the moment use to explain small planets could also be too easy. While this molten planet is unlikely to help life, it displays the broad range of the worlds which exist past the photo voltaic system. We could then ask: what different forms of planets are ready to be uncovered?

Sulfur feeds the ambiance

As famous above, astronomers had already tentatively detected sulfur dioxide (SO2) and hydrogen sulfide (H2S) within the planet’s ambiance. This hinted that the planet was volcanically energetic and/or had a magma ocean below its floor.

Now, the brand new findings counsel that ultraviolet mild from the planet’s star creates these gases when it hits the planet’s ambiance. In flip, the subsurface magma ocean acts as a reservoir for the gases. It’s been storing and releasing them for billions of years. Together, the atmospheric chemistry and subsurface storage have helped make L 98-59 d the planet it’s right now.

A bigger world that shrank

The new findings additionally counsel that L 98-59 d was as soon as bigger than it’s now. Early on, it was extra sub-Neptune in measurement. Sub-Neptunes are smaller than Neptune however bigger than super-Earths. But then it progressively shrank and cooled. And it misplaced a few of its ambiance within the course of.

Scientists additionally mentioned magma oceans are frequent within the early levels of rocky planets. So L 98-59 d can present essential clues about Earth’s primordial historical past billions of years in the past. As co-author Raymond Pierrehumbert on the University of Oxford defined:

What’s thrilling is that we are able to use laptop fashions to uncover the hidden inside of a planet we are going to by no means go to. Although astronomers can solely measure a planet’s measurement, mass and atmospheric composition from afar, this analysis reveals that it’s attainable to reconstruct the deep previous of those alien worlds, and uncover forms of planets with no equal in our personal photo voltaic system.

Does L 98-59 d odor like rotten eggs?

Notably, hydrogen sulfide is without doubt one of the most important elements of the planet’s ambiance. It is pungent, with an odor much like rotten eggs. Does this imply smelly planets are frequent? As Richard Chatterjee on the University of Leeds and University of Oxford famous:

Our laptop fashions simulate numerous planetary processes, successfully enabling us to show again the clock and perceive how this uncommon rocky exoplanet, L 98-59 d, advanced. Hydrogen sulfide gasoline, chargeable for the odor of rotten eggs, seems to play a starring function there. But, as at all times, extra observations are wanted to know this planet and others prefer it. Further investigation could but present that relatively pungent planets are surprisingly frequent.

Bottom line: L 98-59 d is a molten super-Earth exoplanet, with a deep subsurface world ocean of magma. The examine’s outcomes come from new evaluation of information from the James Webb Space Telescope.

Source: Volatile-rich evolution of molten super-Earth L 98-59 d

Via University of Oxford

Read extra: Is this a volcanic exoplanet? Hints are in its ambiance

Read extra: Atmosphere on lava planet is an thrilling shock