‘What the heck is this?’ James Webb telescope spots inexplicable planet with diamonds and soot in its atmosphere
A distant exoplanet appears to sport a smoky atmosphere that is baffling scientists who recently spotted it.
The Jupiter-sized world detected by the James Webb Space Telescope (JWST), does not have the familiar helium-hydrogen combination that we are accustomed to in the atmospheres of our solar system, nor other common molecules, such as water, methane or carbon dioxide.
“It was an absolute surprise,” co-author of the study Peter Gaoa scientist at the Carnegie Earth and Planets Laboratory, said in a statement. “I remember after we got the data back, our collective reaction was, ‘What the hell is that?’ It’s extremely different from what we expected.”
Neutron Sun
Researchers studied the planet’s bizarre environment, known as PSR J2322-2650b, in a paper published Tuesday (December 16) in Letters from the astrophysical journal. Although the planet was detected by a radio telescope in 2017, it took the more precise vision of JWST (launched in 2021) to examine the surroundings of PSR J2322-2650b 750 light years away.
PSR J2322-2650b orbits a pulsar. Pulsars are rapidly rotating neutron stars – the ultradense cores of stars that exploded as supernovas – that emit radiation in short, regular pulses that are only visible when their lighthouse-shaped beams of electromagnetic radiation are aimed directly at Earth. (This is bizarre in itself, because no other pulsar is known to have a gas giant planet, and few pulsars have planets, the science team said.)
JWST’s infrared instruments can’t actually see this particular pulsar because it emits high-energy gamma rays. However, JWST’s “blindness” to the pulsar is actually a boon for scientists because they can easily probe the companion planet, PSR J2322-2650b, to see what the planet’s environment is like.
“This system is unique because we are able to see the planet illuminated by its host star, but not the host star at all,” co-author Maya Beleznaydoctoral student in physics at Stanford University, said in the release. “We can study this system in more detail than normal exoplanets.”
Mystery of training
The origin story of the PSR J2322-2650b is an enigma. It is only a million miles (1.6 million kilometers) from its star, almost 100 times closer than Earth is to the sun. It’s even stranger when you consider that the gas giant planets in our solar system are much farther away: Jupiter is 484 million miles (778 million km) from the sun, for example.
The planet orbits its star in just 7.8 hours, and it is shaped like a lemon because the pulsar’s gravitational forces pull extremely strongly on the planet. At first glance, it appears that PSR J2322-2650b might have a formation scenario similar to that of “black widow” systems, in which a sun-like star sits next to a small pulsar.
In black widow systems, the pulsar “consumes” or erodes the nearby star, much like the myth of the black widow the party behavior of the spider that gives the phenomenon its name. This happens because the star is so close to the pulsar that its material falls onto the pulsar. The additional stellar material gradually causes the pulsar to spin faster and generate a strong “wind” of radiation that erodes the nearby star.
But the main author Michael Zhangpostdoctoral researcher on exoplanet atmospheres at the University of Chicago, said this path makes it difficult to understand how PSR J2322-2650b came to be. In fact, the formation of the planet seems inexplicable at this point.
“Did this thing form like a normal planet? No, because the composition is totally different,” Zhang said in the statement. “It is very difficult to imagine how to obtain this extremely carbon-enriched composition. This seems to rule out any known formation mechanism.”
Diamonds in the air
Scientists still can’t explain how soot or diamonds are present in the exoplanet’s atmosphere. Usually, molecular carbon does not appear on planets very close to their stars, due to extreme heat.
One possibility of what happened comes from the study’s co-author Roger Romaniprofessor of physics at Stanford University and the Kavli Institute of Particle Astrophysics and Cosmology. After the planet cooled following its formation, he suggested, the carbon and oxygen inside crystallized.
But even that doesn’t take into account all the weird properties. “The pure carbon crystals float to the top and mix with the helium… but then something has to happen to push the oxygen and nitrogen away,” Romani explained in the same statement. “And that’s where the mystery [comes] In.”
Scientists hope to continue studying PSR J2322-2650b. “It’s okay not to know everything,” Romani said. “I can’t wait to learn more about the strangeness of this atmosphere. It’s great to have a puzzle to solve.”
