Astronomers have discovered a fascinating planet called L98-59d, which is primarily made of molten lava. This finding opens the door to a completely new category of planets.
L98-59d is about 1.6 times the size of Earth and orbits a small red star around 35 light-years away. Initially, scientists believed it might have a vast ocean of liquid water. However, recent research suggests it’s quite different.
Dr. Harrison Nicholls, an astrophysicist at the University of Oxford, describes the planet as being in a “mushy, molten state.” He likens its surface to molasses. It’s thought that even the core of this planet is molten. The temperatures here soar to a scorching 1,900°C (3,500°F). The tides caused by nearby planets would likely create massive waves across the planet’s magma ocean, and the atmosphere could smell of rotten eggs due to hydrogen sulfide.
While the idea of life existing in such extreme conditions is intriguing, Dr. Nicholls is skeptical. He notes, “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.” However, the unique nature of the planet adds to our understanding of the universe.
Observing worlds beyond our solar system isn’t easy. Historically, astronomers have struggled to gather precise information, relying on silhouettes of planets passing in front of their stars. The James Webb Space Telescope has changed that by analyzing starlight that passes through a planet’s atmosphere, allowing for a clearer understanding of the gases present.
Earlier observations showed that L98-59d has a sulfur-rich atmosphere. This is unusual for a body its size, which typically falls into the categories of being rocky or water-rich. Neither category could maintain such an atmosphere for nearly 5 billion years.
Recent computer simulations have traced L98-59d’s evolution from after its formation to today. These findings indicate a global magma ocean that stretches thousands of kilometers beneath its surface, potentially accompanied by a molten core. Dr. Nicholls explains, “You can only really explain this planet if it has this deep magma ocean inside of it. The magma ocean efficiently stores the gases and keeps them safe from outside processes.”
This discovery suggests that molten planets might be more common than previously thought. As a result, astronomers may need to rethink how they categorize exoplanets, particularly regarding habitability. Dr. Nicholls warns, “Some planets in the so-called habitable zone might not be habitable at all; they could be these molten worlds.”
Dr. Jo Barstow, a planetary scientist at the Open University, adds to this conversation. She was involved in studying L98-59d with the James Webb telescope. She explains that this planet might resemble Jupiter’s moon, Io, which is known for its volcanism. But L98-59d might be even more extreme.
This research is published in Nature Astronomy. The discovery not only expands our knowledge of exoplanets but also raises more questions: What other types of planets are yet to be discovered? As technology advances, our understanding of these distant worlds will continue to grow.
