• Composed of molten lava, unlike any known planet
• Its surface temperature exceeds 1900°C, and its atmosphere is rich in sulfur gas

Astronomers have discovered a planet made of molten lava, potentially representing an entirely new class of liquid planets.

The distant world, designated L98-59d, is roughly 1.6 times the size of Earth and orbits a small red star about 35 light-years away.

Initially, scientists thought the planet might host a deep ocean of liquid water. However, recent analyses reveal it is radically different from any previously known planet.

Dr. Harrison Nichols, an astronomer at the University of Oxford, said, “The planet exists in a semi-liquid, molten state, resembling thick honey, and its core is likely molten as well.”

Surface temperatures reach around 1900°C, and enormous waves are expected to form in the lava ocean due to gravitational forces from nearby planets. The atmosphere is filled with the sulfurous scent of hydrogen sulfide gas.

Researchers note that these extreme conditions make the planet unsuitable for life.

The findings are based on observations from the James Webb Space Telescope, which measures light from distant stars and analyzes the gases in exoplanet atmospheres, rather than relying solely on estimates of size, density, or temperature.

Observations show that L98-59d’s atmosphere is sulfur-rich, setting it apart from traditional rocky or water-based planets. Such conditions could not have formed over billions of years if it were composed like these familiar planet types.

Using advanced computer simulations, scientists reconstructed the planet’s history from its formation to the present, revealing a global lava ocean extending thousands of kilometers beneath its surface, and possibly a molten core.

Nichols added, “This planet can only be explained if it possesses this deep lava ocean, which stores gases and protects them from physical processes that might otherwise remove them.”

The results suggest molten planets may be more common than previously thought, urging caution when classifying distant worlds as potentially habitable.

Nichols also said, “Some planets in the so-called habitable zone may not actually be suitable for life—they could be molten worlds like this one. While this planet is unlikely to support life, it highlights the incredible diversity of worlds beyond our solar system.”

Dr. Jo Barstow, a planetary scientist at the Open University involved in L98-59d observations, added, “We considered the possibility that this planet resembles Jupiter’s moon Io, covered in volcanoes due to tidal heating, but the new data suggest an even more extreme environment.”