Astronomers Identify 'Hellish' Molten World in Nearby Star System
Astronomers have made a remarkable discovery in our galactic neighborhood, spotting a molten alien planet whose surface conditions resemble a vision of hell. The planet, designated L 98-59 d, is completely covered in magma and enveloped by a fiercely hot, sulfur-rich atmosphere that creates an environment utterly inhospitable to life as we know it.
A Planet of Molten Rock and Toxic Atmosphere
The newly characterized exoplanet has a diameter approximately 60% larger than Earth's, though its density measures only about 40% of our planet's. Located approximately 34 light-years from Earth in the constellation Volans, L 98-59 d orbits a red dwarf star that is both dimmer and smaller than our sun, with only about 30% of the sun's mass and 1% of its luminosity.
"The planet lacks distinct structure within its magma ocean, so there is no crust, upper mantle and lower mantle. The magma ocean is a single deep, mushy layer," explained Harrison Nicholls, a postdoctoral researcher at the University of Cambridge Institute of Astronomy and lead author of the research published in Nature Astronomy.
This molten world features a relatively small metallic core, with the magma ocean comprising an astonishing 70-90% of the planetary interior radius. This translates to a magma depth ranging between 2,775 and 3,565 miles (4,465-5,740 kilometers). Within this turbulent fluid magma, small crystals of solid rock may be trapped, according to the research team.
The Sulfur-Rich Atmosphere and Runaway Greenhouse Effect
The planet's thick atmosphere presents one of its most distinctive characteristics. Primarily composed of hydrogen, the atmosphere contains an exceptionally high sulfur content, with approximately 10% consisting of hydrogen sulfide - the toxic gas responsible for the odor of rotten eggs.
"Your nose can smell hydrogen sulfide at concentrations of something like one part per billion, so this would be overwhelmingly stinky. But you wouldn't survive long enough in this hot atmosphere to notice," noted planetary scientist Raymond Pierrehumbert of the University of Oxford and Massachusetts Institute of Technology, who co-authored the study.
This sulfur-laden atmosphere has created a runaway greenhouse effect, trapping heat from the host star and maintaining surface temperatures in excess of 1,500 degrees Celsius (2,732 degrees Fahrenheit). The atmospheric composition suggests a correspondingly high sulfur content within the planetary interior itself.
Discovery and Analysis of an Ancient World
L 98-59 d was initially discovered in 2019, with subsequent observations conducted by the James Webb Space Telescope in 2024 and ground-based telescopes in 2025. Researchers employed advanced computer simulations to reconstruct the planet's history, revealing it to be nearly five billion years old - slightly older than Earth's estimated age of 4.54 billion years.
The planet represents the third of five known planets orbiting its host star. While astronomers have discovered more than 6,100 exoplanets beyond our solar system since the 1990s, L 98-59 d stands out for its unique combination of a global magma ocean and sulfur-dominated atmosphere.
"This planet's surface is in excess of 1,500 degrees Celsius, so it would not harbour life as we know it," emphasized Nicholls, confirming that despite its intriguing characteristics, this molten world remains firmly in the category of uninhabitable planets.
The discovery provides valuable insights into planetary formation and atmospheric evolution, particularly around red dwarf stars - the most common type of star in our galaxy. As observational technology continues to advance, astronomers anticipate discovering more extreme worlds that challenge our understanding of planetary science.
