An international team of astronomers led by researchers from the EXOTIC laboratory of the University of Liège, in collaboration with the Massachusetts Institute of Technology and the Institute of Astrophysics of Andalusia, has discovered an “impossible” giant planet with a density comparable to that of sweet cotton .
The study was published in the journal Nature Astronomy and is briefly described by Phys.org. The giant planet was designated WASP-193b. It has an extremely low density and orbits a distant star similar to our Sun. The planet is located at a distance of 1200 light years from Earth.
Calculations showed that its diameter is 50 percent larger than the diameter of Jupiter, but it is 7 times lighter than Jupiter. The parameters helped calculate its density, which turned out to be close to the density of cotton candy.
“WASP-193b is the second least dense planet discovered to date, after Kepler-51d, which is much smaller,” says lead author Khalid Barkaoui. “Its extremely low density makes it a true anomaly among the more than 5,000 exoplanets discovered so far. .” Today, this extremely low density cannot be reproduced by standard models of gas giants, even if the unrealistic scenario of the structure of a coreless planet is considered.”
The planet was discovered as part of the Wide Angle Search for Planets (WASP) project. The observatory has been collecting the necessary data since 2006. The accumulated information made it possible to establish that the planet passes in front of the star, blocking its light to the observer, every 6.25 days.
The existence of the anomalous planet was later confirmed by independent research, as well as by a team of discoverers, but with the help of the TRAPPIST-South and SPECULOOS-South observatories. Observations from the HARPS and CORALIE spectrographs located in Chile helped to finally confirm the existence of a planet that “should not exist.”
Spectrographic measurements made it possible to precisely determine the mass and density of the giant planet. Much to the scientists’ surprise, the measured density was only 0.059 grams per cubic centimeter. For comparison, Jupiter’s density is approximately 1.33 grams per cubic centimeter, Earth’s is 5.51 grams per cubic centimeter.
“One of the materials closest in density to the newly discovered puffy planet is cotton candy, which has a density of about 0.05 grams per cubic centimeter,” said Julien de Wit, a professor at the Massachusetts Institute of Technology. “It’s hard to imagine a similar solid material. The reason it has a similar density to cotton candy is because both the planet and the cotton candy are largely made of air. The planet is essentially very spongy.”
