Astronomers Uncover a New Category of Liquid Planet: A Molten Lava World
In a groundbreaking discovery, astronomers have identified a distant planet composed entirely of molten lava, potentially heralding the existence of an entirely new type of liquid planet. This finding challenges previous assumptions about planetary composition and habitability in the cosmos.
The Lava Planet: L98-59d
The planet, known as L98-59d, is located approximately 35 light years from Earth and orbits a small red star. With a size about 1.6 times that of our planet, initial observations had suggested it might host a deep ocean of liquid water. However, the latest analysis reveals a far more extreme environment.
Dr Harrison Nicholls, an astrophysicist at the University of Oxford, described the planet as being in a "molten, mushy state", akin to molasses. He noted that the core is likely also molten, with surface temperatures soaring to a blistering 1,900°C (3,500°F).
Hostile Conditions and Atmospheric Composition
The conditions on L98-59d are far from conducive to life as we know it. Large waves are believed to roll over its magma ocean, driven by tidal forces from neighbouring planets. Additionally, the atmosphere is rich in hydrogen sulphide, emitting a pervasive stench of rotten eggs.
"If there are aliens out there that could live in lava that would be amazing, but I don't think it's likely that it's habitable," said Nicholls. "It's nice to revel in the alienness of the planet itself."
Advanced Observations and Simulations
Until recently, studying exoplanets like L98-59d was limited to crude estimates based on their silhouettes as they passed in front of their host stars. The James Webb Space Telescope has revolutionised this field by enabling detailed analysis of starlight filtered through planetary atmospheres.
Previous observations indicated a sulphur-rich atmosphere, which did not align with conventional categories of rocky or water worlds. Advanced computer simulations have now reconstructed the planet's history, suggesting a global magma ocean extending thousands of kilometres beneath the surface.
"You can only really explain this planet if it has this deep magma ocean inside of it," Nicholls explained. "The magma ocean efficiently stores the gases and keeps them protected from processes that would otherwise remove them."
Implications for Planetary Science
This discovery implies that molten planets may be more common than previously thought, prompting astronomers to reconsider how they designate exoplanets as potentially habitable. "Some planets in the so-called habitable zone might not be very habitable at all, they might be these molten planets," Nicholls cautioned.
Dr Jo Barstow, a planetary scientist at the Open University involved in the observations, added that the findings provide a plausible explanation, suggesting L98-59d could be even more extreme than Jupiter's volcanic moon Io.
The research, published in the journal Nature Astronomy, highlights the incredible diversity of worlds beyond our solar system and opens new questions about what other types of planets await discovery.
