According to ScienceAlert, the James Webb Space Telescope has revealed the bizarre details of an exoplanet called PSR J2322-2650b, located 2,055 light-years away. It orbits a millisecond pulsar, PSR J2322-2650, completing a revolution every 7.8 hours and is about 80% the mass of Jupiter. The planet is stretched into a lemon shape by the pulsar’s gravity, its atmosphere is heated to 1,900 Kelvin by gamma radiation, and it’s rotating in the opposite direction of its atmospheric winds. Most shockingly, its atmosphere is dominated by molecular carbon instead of common molecules like water or methane, a composition that, as astronomer Michael Zhang states, “seems to rule out every known formation mechanism.” The discovery, made possible because JWST can see the planet without seeing the pulsar’s blinding radiation, has left scientists utterly stumped.
Why this planet shouldn’t exist
Here’s the thing: planets aren’t supposed to survive the supernova that creates a neutron star. The sheer violence of that explosion should vaporize anything in the vicinity. So the very existence of this world, whipping around a pulsar that spins every 3.46 milliseconds, is the first major puzzle. The leading theory isn’t that it survived, but that it formed from the aftermath. Astronomers think this “planet” might have started as the pulsar’s binary companion star—specifically, a helium star. Over eons, the pulsar acted like a cosmic black widow spider, slowly stripping and devouring its mate until it was whittled down to a planetary mass. That explains the helium interior. But it doesn’t fully explain the carbon atmosphere.
The carbon conundrum
This is where it gets truly weird. JWST didn’t find the usual atmospheric suspects. Instead, it found molecular carbon (C and C₂). One idea is that as the devoured companion star cooled, carbon crystals floated up from its interior and got mixed into the helium atmosphere. But that leaves a big question: where’s all the oxygen and nitrogen that should also be there? It’s like finding a cookie made of nothing but chocolate chips—no dough, no other ingredients. Just chips. This pure carbon signature is unprecedented and suggests crystallization processes, maybe even diamond rain deeper down, that we’ve never observed directly. It’s a completely new class of atmospheric chemistry that challenges our basic assumptions.
A system of extremes
Let’s talk about the environment. Imagine a world so close to its star that its atmosphere is stretched into a football shape. Now imagine that star isn’t shining with light, but blasting it with gamma radiation, heating it hundreds of degrees hotter than starlight alone could. And on top of that, the super-rotating atmosphere is racing westward while the planet spins eastward. It’s a maelstrom of extremes. The only reason we can see it so clearly is JWST’s unique infrared vision, which ignores the pulsar’s radio and gamma beams. As astronomer Maya Beleznay noted, this gives a “pristine spectrum” of the planet alone—a rare and perfect observational window. Basically, we got lucky with a natural experiment in planetary butchery and atmospheric physics.
Blurring the cosmic lines
So what do we even call this thing? It’s not a planet by any standard formation model. It’s not a brown dwarf. It’s the stripped-down corpse of a star, masquerading as a planet. This discovery, detailed in prior research and followed up by JWST, brilliantly blurs the line between stellar and planetary bodies. And that’s exciting. It forces astrophysicists to reconsider their categories and models. As researcher Roger Romani put it, “It’s nice to not know everything.” This lemon-shaped oddity is a stark reminder that the universe is far more inventive than we are. Our catalogs and theories are just provisional sketches, and the cosmos is always ready to throw a wrench—or a carbon-covered, backwards-spinning lemon—into the works.
