NASA’s Webb telescope just discovered one of the weirdest planets ever
A newly discovered exoplanet is rewriting the rules of what planets can be. Orbiting a city-sized neutron star, this Jupiter-mass world has a bizarre carbon-rich atmosphere filled with soot clouds and possibly diamonds at its core. Its extreme gravity stretches it into a lemon shape, and it completes a full orbit in under eight hours. Scientists are stunned — no known theory explains how such a planet could exist.
Scientists using NASA's James Webb Space Telescope have identified a previously unknown kind of exoplanet, one whose atmosphere defies current ideas about how planets are supposed to form.
The newly observed world has a stretched, lemon-like shape and may even contain diamonds deep inside. Its strange characteristics make it difficult to classify, sitting somewhere between what astronomers typically consider a planet and a star.
A Carbon World Unlike Any Other
The object, officially named PSR J2322-2650b, has an atmosphere dominated by helium and carbon rather than the familiar gases seen on most known exoplanets. With a mass comparable to Jupiter, the planet is shrouded in dark soot-like clouds. Under the intense pressures inside the planet, scientists believe carbon from these clouds could be compressed into diamonds. The planet circles a rapidly spinning neutron star.
Despite detailed observations, how this planet formed remains unknown.
"The planet orbits a star that's completely bizarre -- the mass of the Sun, but the size of a city," said University of Chicago astrophysicist Michael Zhang, the study's principal investigator. The research has been accepted for publication in The Astrophysical Journal Letters. "This is a new type of planet atmosphere that nobody has ever seen before."
"This was an absolute surprise," said Peter Gao of the Carnegie Earth and Planets Laboratory in Washington, D.C. "I remember after we got the data down, our collective reaction was 'What the heck is this?'"
A Planet Orbiting a Pulsar
PSR J2322-2650b orbits a neutron star, also known as a pulsar, that spins at extraordinary speed.
Pulsars emit powerful beams of electromagnetic radiation from their magnetic poles at intervals measured in milliseconds. Most of that radiation comes in the form of gamma rays and other high-energy particles that are invisible to Webb's infrared instruments.
Because the star itself does not overwhelm Webb's detectors, researchers can observe the planet throughout its entire orbit. This is rarely possible, since most stars shine far brighter than the planets around them.
"This system is unique because we are able to view the planet illuminated by its host star, but not see the host star at all," said Maya Beleznay, a Stanford University graduate student who helped model the planet's shape and orbit. "So we get a really pristine spectrum. And we can better study this system in more detail than normal exoplanets."
A Startling Atmospheric Discovery
When scientists analyzed the planet's atmospheric signature, they found something entirely unexpected.
"Instead of finding the normal molecules we expect to see on an exoplanet -- like water, methane and carbon dioxide -- we saw molecular carbon, specifically C3 and C2," Zhang said.