A bizarre exoplanet named PSR J2322-2650b, orbiting a rapidly spinning neutron star, has been detected more than 2000 light years away. Its atmosphere contains molecular carbon, defying expectations for such worlds. The planet's unusual shape and extreme conditions puzzle scientists.
Astronomers led by Michael Zhang at the University of Chicago have identified one of the strangest exoplanets known, PSR J2322-2650b, using the James Webb Space Telescope. Located over 2000 light years from Earth, this world orbits a pulsar, a type of rapidly spinning neutron star, which is already an uncommon setup for planetary systems.
The planet's light spectrum revealed an unexpected composition: molecules of carbon in its atmosphere, rather than the typical water and carbon dioxide found on Jupiter-mass planets. "In order to have molecular carbon in the atmosphere, you have to get rid of pretty much everything else, all of the oxygen, all of the nitrogen, and we just don’t know how to do that," Zhang explained. He added, "We don’t know of any other planetary atmosphere that looks anything like this."
Due to its close orbit around the massive pulsar, the exoplanet has been distorted into an oblong, lemon-like shape. A full year on the planet lasts just 7.8 hours, with even the coldest spots reaching about 650°C (1202°F). Unlike most giant planets, its winds blow counter to its rotation. Zhang described it vividly: "You can imagine that this planet would look deep red, with clouds of graphite in the atmosphere, like a sort of evil lemon." He called it "definitely the weirdest exoplanet."
These peculiarities challenge current models of planet formation, leaving the origins of PSR J2322-2650b a mystery. The findings appear in The Astrophysical Journal Letters (DOI: 10.3847/2041-8213/ae157c).