JWST Finds Lemon-Shaped Exoplanet with Diamond-Rain Atmosphere

A Truly Bizarre World: The Lemon-Shaped Exoplanet

Astronomers using the James Webb Space Telescope have observed one of the most unusual planets ever seen: PSR J2322-2650b, a lemon-shaped exoplanet orbiting a millisecond pulsar. Its distorted shape, extreme atmosphere, and peculiar chemical composition defy current planetary formation theories, making this one of the most puzzling cosmic discoveries in recent memory.

What Makes PSR J2322-2650b So Strange?

PSR J2322-2650b is an exoplanet roughly the mass of Jupiter that orbits a rapidly spinning neutron star (a millisecond pulsar) at an extremely close distance — just about 1 million miles from its host. This tight orbit gives the planet a year of only ~7.8 hours and stretches its shape due to huge gravitational tides, giving it a distinctive elongated “lemon” look.

But the oddness goes far deeper than shape.

Exotic Atmosphere and Diamond Potential

Infrared observations from JWST reveal that PSR J2322-2650b’s atmosphere is dominated by helium and molecular carbon (C₂ and C₃), with a near absence of oxygen and nitrogen — unlike any other planet studied so far.

Scientists think soot-like carbon clouds may form under intense pressure, and deep within the planet’s atmosphere, carbon may condense into diamonds — potentially creating rain of diamonds falling toward the hot core.

Orbit, Environment, and Extreme Conditions

Because the planet orbits extremely close to a pulsar — the collapsed core of a massive star — tidal forces have stretched it into an ellipsoid shape, with equatorial diameter significantly larger than its polar diameter.

Temperatures on PSR J2322-2650b vary widely:

• Dayside: ~3,700 °F (2,038 °C)
• Nightside: ~1,200 °F (649 °C)

The unusual environment and pulsar radiation also illuminate the planet in infrared, making detailed atmospheric study possible.

Challenging Planetary Formation Theory

This exoplanet’s existence and composition challenge every known model of planetary formation. Researchers expected that planets orbiting extreme remnants like pulsars would be simple and stripped down, but PSR J2322-2650b’s rich carbon atmosphere and exotic chemistry raise fundamental questions about how such a world could form and persist.

“This is a new type of planetary atmosphere that nobody has ever seen before,” explained scientists involved in the study, highlighting the genuine surprise and scientific excitement around this discovery.

Scientific and Public Impact

The discovery of PSR J2322-2650b has captured both scientific and public imagination due to:

• Its unprecedented atmosphere and composition
• The strange, lemon-like shape created by tidal forces
• Diamond condensation deep in the atmosphere
• Extreme orbital and temperature conditions

This exoplanet is now one of the most discussed objects in astronomy for 2026, prompting research into planetary formation in extreme environments.

Future Research and Follow-Up

Scientists will continue using JWST and other observatories to:

• Model the planet’s atmospheric dynamics
• Search for more exotic exoplanets in pulsar systems
• Understand how carbon-rich atmospheres develop under such conditions

PSR J2322-2650b stands as a benchmark discovery that may expand planetary classification and formation theory in the coming years.