Breaking Update: Here’s a clear explanation of the latest developments related to Breaking News:Astronomers discover a new planet type with a vast magma ocean– What Just Happened and why it matters right now.
Astronomers have discovered an entirely new kind of planet outside our Solar System, one with a colossal ocean of molten rock underneath its surface. The finding upends current systems for categorizing distant planets.
The new planet, called L 98-59 d, was studied with data from the James Webb Space Telescope combined with sophisticated computer models. It orbits a small red star some 35 light-years from Earth and holds large reserves of sulfur embedded deep beneath a global magma ocean, researchers found.
The study, led by astronomers at the University of Oxford, suggests that many more exotic, previously unknown types of planets exist throughout the galaxy.
Lead author Dr. Harrison Nicholls (Department of Physics, University of Oxford) said: “This discovery suggests that the categories astronomers currently use to describe small planets may be too simple.”
Most small exoplanets fall into one of two categories: rocky worlds that have only a tenuous atmosphere or ocean planets that are covered by a thick ocean. But L 98-59 d does not fit either description. Instead, it seems to indicate a whole new class of sulfur-rich planets with molten interiors.
Despite being roughly 1.6 times the size of our planet, L 98-59 d has a surprisingly low density. The team used sophisticated computer simulations to track the planet’s evolution over nearly 5 billion years. By correlating those telescope observations with fine details of models of its interior and atmosphere, they learned about the processes that were taking place deep inside the planet.
Observations found that its atmosphere contained gases containing sulfur, such as hydrogen sulfide. And the planet’s interior is dominated by a superdeep ocean of molten silicate rock thousands of kilometers deep.
That magma ocean acts as a reservoir for sulfur, slowly releasing it into the atmosphere over billions of years. Magma ocean: a thick hydrogen-rich atmosphere, containing gases such as H₂S. Without that, the star’s X-ray radiation erodes this atmosphere with age.
Dr Nicholls said, “While this molten planet is unlikely to support life, it reflects the wide diversity of the worlds which exist beyond the Solar System. We may then ask: what other types of planets are waiting to be uncovered?”
Researchers integrated telescope observations with detailed simulations of planetary evolution to piece together the planet’s history over nearly 5 billion years. They also considered how radiation emitted by L 98-59 itself induces chemical reactions in the atmosphere, producing sulfur gases.
The existing division of exoplanets into classes may be too straightforward, because there might exist many more types of planets with their own different chemical and physical properties. Understanding magma oceans is important because they are among the earliest stages in the evolution of rocky planets, including Earth.
Simulations indicate that the planet began with a significant inventory of volatiles and may have originally resembled a larger sub-Neptune. Over time, it cooled, lost some of its atmosphere, and shrank. Since magma oceans form the foundation beneath all rocky planets, including Earth and Mars, learning more about them may give us insights into our own planet’s infancy.
Co-author Professor Raymond Pierrehumbert (Department of Physics, University of Oxford) said: “What’s exciting is that we can use computer models to uncover the hidden interior of a planet we will never visit. Although astronomers can only measure a planet’s size, mass, and atmospheric composition from afar, this research shows that it is possible to reconstruct the deep past of these alien worlds – and discover types of planets with no equivalent in our own Solar System.”
The discovery opens the door to discovering an entire population of similar sulfur-rich worlds throughout the galaxy. With new missions and data from JWST, scientists hope not just to chart the diversity of worlds beyond our own but also to square their models of how these planets formed and evolved, as well as pinpoint which ones could harbor life.
Journal Reference:
- Nicholls, H., Lichtenberg, T., Chatterjee, R.D. et al. Volatile-rich evolution of molten super-Earth L 98-59 d. Nat Astron (2026). DOI: 10.1038/s41550-026-02815-8