Using the James Webb Space Telescope, researchers detected a Jupiter-mass object, PSR J2322-2650b, orbiting a pulsar and stretched into a lemon-like shape by extreme tidal forces. Its emission spectrum shows strong carbon features but no detectable nitrogen or oxygen—an unexpected chemical signature that defies standard formation models. Scientists propose possibilities ranging from a stripped stellar remnant to a new class of object, and say further observations are needed.
Weird Lemon-Shaped Exoplanet Lacking Nitrogen and Oxygen Discovered by JWST
Astronomers using the James Webb Space Telescope have identified a bizarre, lemon-shaped exoplanet with an atmosphere rich in carbon but apparently missing both nitrogen and oxygen. The object — dubbed PSR J2322-2650b — challenges conventional ideas about planet formation and composition.
Discovery and Atmospheric Findings
Observations with JWST examined the planet's emission spectrum and revealed wavelengths consistent with molecular carbon. According to Michael Zhang, a postdoctoral researcher at the University of Chicago and co-author of a preprint describing the results, "Everywhere in the universe, where there’s carbon, there tends to be nitrogen and oxygen." The absence of detectable nitrogen and oxygen in PSR J2322-2650b's atmosphere is therefore striking and puzzling. The team’s study is slated to appear in the Astrophysical Journal Letters.
Host Star and Extreme Shape
PSR J2322-2650b is roughly the mass of Jupiter but orbits a pulsar — a compact, rapidly rotating neutron star that emits beams of electromagnetic radiation from its poles. Because the planet is relatively massive and lies close to its pulsar host, tidal forces distort it into an extreme, lemon-like shape. While tidal deformation has been seen in gas giants around ordinary stars, the effect here appears far more pronounced.
Possible Interior and Formation Scenarios
The carbon signal raises the intriguing possibility that carbon is abundant throughout the planet and may even form diamond-like material in its deep interior. One hypothesis is that PSR J2322-2650b is the stripped remnant of a former star, but that scenario does not easily explain the lack of nitrogen and oxygen. Zhang and colleagues acknowledge the difficulty of reconciling the observations with conventional formation models and say they are open to the object representing a new class of astrophysical body.
Next Steps
Further observations and modeling will be needed to confirm the atmospheric composition, probe the planet's internal structure, and test formation scenarios. Future JWST measurements, complementary telescopes, and theoretical work may help resolve whether this object is an extreme planet, a stellar remnant, or something entirely new.
Quote: "It’s really hard to explain by conventional means," Zhang says, noting the discovery may point to an entirely new type of object.
