Webb Telescope Observes Lemon-Shaped Jupiter-Mass Object Orbiting Pulsar

The James Webb Space Telescope has studied PSR J2322-2650b, a Jupiter-mass object orbiting a rapidly spinning pulsar more than 2,000 light-years from Earth, and found its equatorial diameter to be about 38 percent wider than its polar diameter, giving the world a lemon-like shape.

PSR J2322-2650b was discovered in 2011 by the Parkes radio telescope in Australia and is the only gas giant known to orbit a pulsar. The planet sits roughly one million miles from its star and completes an orbit in about eight hours; the pulsar’s strong gravity appears to pull material from the object, with Peter Gao of the Carnegie Institution for Science saying, “You have a literal tip, like a point, where material actually comes out of the planet and spirals in.” Webb’s infrared observations—the first atmospheric study of a body orbiting a pulsar—showed the object is largely devoid of hydrogen, oxygen and nitrogen and is instead made mostly of helium and molecular carbon.

Scientists cautioned that the object’s origins are uncertain. Gao said the team “favor the star scenario,” where the body is the remnant of a star being eaten by the pulsar, possibly having lost 99.9 percent of its mass, while Michael Zhang said it could be “an entirely new type of object.” Zhang said he hopes to look for more such worlds to determine whether this object is in its final moments or a stable, long-lived system.

Key Topics

Science, James Webb Telescope, Parkes Radio Telescope, Pulsar, Black Widow Pulsar, Michael Zhang