Astronomers using NASA’s James Webb Space Telescope have discovered an exoplanet, PSR J2322-2650b, orbiting a small, dense pulsar, forming a black widow pair with the pulsar and a smaller astronomical body.
The exoplanet orbits in close proximity to the pulsar, where the star’s intense gravitational pull has distorted it into an oblong, lemon shape. The spectroscopic analysis of the atmosphere revealed it consists mainly of helium and carbon, including molecular carbon.
This composition differs from typical exoplanet atmospheres, which usually contain water, methane, or carbon dioxide. The carbon-rich makeup challenges known planet-formation mechanisms, making it difficult to understand how such a composition could occur.
Peter Gao of the Carnegie Earth and Planets Laboratory in Washington, a co-author on the study, recalled the team’s reaction upon receiving the data: “I remember after we got the data down, our collective reaction was ‘What the heck is this?’ It’s extremely different from what we expected.”
Principal investigator Michael Zhang of the University of Chicago noted the unusual findings, saying, “Instead of finding the normal molecules we expect to see on an exoplanet — like water, methane, and carbon dioxide — we saw molecular carbon.” Zhang further emphasized the challenge in explaining the exoplanet’s composition, stating, “It’s very hard to imagine how you get this extremely carbon-enriched composition. It seems to rule out every known formation mechanism.”
