A distant exoplanet appears to have a sooty atmosphere, confusing scientists who recently discovered it.
A world the size of Jupiter, discovered by James Webb Space Telescope (JWST), does not contain the familiar helium-hydrogen combination we are accustomed to in our solar system’s atmosphere, nor other common molecules, such as water, methane, or carbon dioxide.
“This was an absolute surprise,” said study co-author Peter ZhaoA scientist at the Carnegie Earth and Planetary Laboratory in A statement. “I remember after we got the data, our collective reaction was: What the hell is this?” “It’s completely different from what we expected.”
Neutron sun
Researchers studied the alien environment of the planet, known as PSR J2322-2650b, in a paper published Tuesday (December 16) in the journal Astrophysical Journal Letters. Although the planet was discovered by a radio telescope survey in 2017, it took a sharper view from the James Webb Space Telescope (launched in 2021) to examine the environment of PSR J2322-2650b from a distance of 750 light-years.
PSR J2322-2650b orbits a pulsar. Pulsars are rapidly rotating neutron stars — the ultra-dense cores of stars that have exploded as supernovas — that emit radiation in short, regular pulses that can only be seen when their lighthouse-like beams of electromagnetic radiation are aimed directly at Earth. (This is strange in itself, as no other pulsar is known to have a gas giant planet, and few pulsars have planets at all, the science team said.)
The infrared instruments on the James Webb Space Telescope cannot see this particular pulsar because it is emitting high-energy gamma rays. However, the James Webb Space Telescope’s “blindness” to the pulsar is actually a blessing for scientists because they can easily explore 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 we do not see the host star at all,” co-author Maya BeleznayA doctoral candidate in physics at Stanford University said in the statement. “We can study this system in more detail than regular exoplanets.”
The secret of formation
The origin story of PSR J2322-2650b is a mystery. It is only 1 million miles (1.6 million kilometers) from its star — nearly 100 times closer than Earth is to the sun. This is 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 kilometers) from the Sun, for example.
The planet orbits its star in just 7.8 hours, and is shaped like a lemon because the gravitational forces of the pulsar pull so strongly on the planet. At first glance, it appears that PSR J2322-2650b could have a formation scenario similar to the “Black Widow” systems, where a Sun-like star is located next to a small pulsar.
In black widow systems, the pulsar “consumes” or erodes the neighboring star, just like a pulsar The legend of the black widow The behavior of the spider at banquets, after which the phenomenon is named. This happens because the star is so close to the pulsar that its material falls onto the pulsar. The extra stellar matter causes the pulsar to spin progressively faster and generate powerful “winds” of radiation that erode the nearby star.
But the main author Michael ChangThis trajectory made it difficult to understand how PSR J2322-2650b came to be, said a postdoctoral fellow in exoplanetary atmospheres at the University of Chicago. In fact, the planet’s formation seems inexplicable at this point.
“Did this thing look like a regular planet? No, because the composition is completely different,” Zhang said in the statement. “It’s very difficult to imagine how you get this extremely carbon-rich composition. It seems to rule out every known formation mechanism.”
Diamonds in the air
Scientists still cannot explain how soot or diamonds could exist in the exoplanet’s atmosphere. Normally, molecular carbon does not appear in planets that are very close to their stars, due to the intense heat.
One possibility for what happened comes from a co-author of the study Roger Romanprofessor of physics at Stanford University and the Kavli Institute for Molecular Astrophysics and Cosmology. He suggested that after the planet cooled from its formation, the carbon and oxygen in its interior crystallized.
But even this does not take into account all individual characteristics. “The pure carbon crystals float to the top and mix with the helium, but then something has to happen to keep the oxygen and nitrogen away,” Roman explained in the same statement. “And this is where the mystery lies [comes] in.”
Scientists hope to continue studying PSR J2322-2650b. “It’s nice not to know everything,” Roman said. “I’m looking forward to learning more about the strangeness of this atmosphere. It’s great to have a mystery to research.”