K. Ivanov
The extremely low-density planet called WASP-193b is larger than Jupiter but a fraction of its mass.
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What’s big with a fluffy texture that looks like cotton candy? It turns out a planet.
An international coalition of astronomers recently discovered an unusual planet, dubbed WASP-193b, that is about 50% larger than Jupiter, and still by far the second-lightest planet ever discovered.
But WASP-193b, which lies outside our solar system about 1,200 light-years from Earth, is not just a scientific oddity. The exoplanet could also be key to future research investigating the formation of atypical planets, according to a study describing the discovery published Tuesday in the journal. Nature astronomy.
This cotton candy planet is not alone; There are other similar planets that belong to a category that scientists call “bulging Jupiters.” The lightest planet ever discovered is the extremely bloated planet Kepler 51 dIt is roughly the size of Jupiter but 100 times lighter than the gas giant.
Khaled Al-Barqawi, the study’s lead author, said bulging Jupiters have largely remained a mystery for 15 years. But WASP-193b, due to its size, is an ideal candidate for further analysis by the James Webb Space Telescope and other observatories.
“The planet is so light that it is difficult to think of similar material in the solid state,” said Al-Barqawi, a postdoctoral researcher in Earth, atmospheric and planetary sciences at MIT. press release. “The reason it’s close to cotton candy is because both are made mostly of light gases rather than solids. The planet is basically very thin.”
WASP-193b, which researchers believe is made up mostly of hydrogen and helium, was a big mystery for researchers to piece together. Because the exoplanet’s density is very light relative to its size, calculating its mass has become a challenge.
Typically, scientists determine mass using a technique called radial velocity, in which researchers analyze how the star formed DomainIt is a graph that indicates the intensity of light emissions at wavelengths, and it changes as the planet rotates around it. The larger the planet, the more the star’s spectrum can shift, but this didn’t work for WASP-193b, which is so light, it made no impact on the star that the team could detect.
Al-Barqawi explained that because of the small size of the cluster signal, it took the team four years to collect data and calculate the mass of WASP-193b. Because the extremely low numbers they found were so rare, the researchers completed multiple experiments to analyze the data, just to be sure.
“We were initially getting very low densities, which was very hard to believe at first,” co-lead author Francisco Pozuelos, a senior researcher at Spain’s Andalusian Astrophysical Institute, said in a press release.
In the end, the team discovered that the planet’s mass does not exceed 14% of the mass of Jupiter, despite it being much larger.
But larger size means a larger “extended atmosphere,” said study co-author Julian de Wit, associate professor of planetary science at MIT. This means that WASP-193b provides a particularly useful window into the formation of these bulge planets.
“The larger the planet’s atmosphere, the more light can pass through it,” De Wit told CNN. “So this planet is clearly one of the best targets we have for studying atmospheric effects. It will serve as a Rosetta Stone for trying to solve the mystery of bulging Jupiters.”
It’s also not clear how WASP-193b formed, Barqawi said. The “classical evolutionary models” of gas giants do not fully explain this phenomenon.
“WASP-193b is a more exotic planet than all the planets discovered so far,” he said.
