NASA’s James Webb Space Telescope (JWST) has found something starkly unique on the exoplanet WASP-107b. The telescope has detected atmospheric asymmetry on the exoplanet, something that is not found in our solar system. Experts say even among exoplanets, this phenomenon has never been observed.
Researchers from the University of Arizona, along with an international group of scientists, studied the hot and uniquely inflated exoplanet. It is about the size of Jupiter but is only a tenth of its mass and has east-west asymmetry in its atmosphere. This means that the two edges of its atmosphere are significantly different.
The study has been published in the journal Nature Astronomy.
“This is the first time the east-west asymmetry of any exoplanet has ever been observed as it transits its star, from space,” lead author Matthew Murphy, a graduate student at the University of Arizona Steward Observatory, said.
Stating that JWST helped them make the astonishing discovery, Murphy said, “I think observations made from space have a lot of different advantages versus observations that are made from the ground.”
This asymmetry means that temperature or cloud properties differ between the eastern and western hemispheres of the planet.
Notably, exoplanet WASP-107b is tidally locked to its star, which means one hemisphere is always facing the star while the other side is always dark. So there is a permanent day side and a permanent night side of the exoplanet.
Using the transmission spectroscopy technique, the telescope took a series of pictures of the planet as it passed in front of its host star. Using the special tools at their disposal, the researchers separated the signals of the atmosphere’s eastern and western sides.
They then looked at specific processes happening in the exoplanet’s atmosphere.
WASP-107b is unique
WASP-107b has a temperature of roughly 890 degrees Fahrenheit. It has a very low density and relatively low gravity, which translates to a more inflated atmosphere than other exoplanets of its mass.
“We don’t have anything like it in our own solar system. It is unique, even among the exoplanet population,” Murphy said.
Thomas Beatty, study co-author and an assistant professor of astronomy at the University of Wisconsin-Madison, said, “This is really the first time that we’ve seen these types of asymmetries directly in the form of transmission spectroscopy from space.”