Um planeta semelhante a algodão doce
This cotton candy planet isn't alone; there are other similar planets belonging to 🏧 a class scientists facetiously call "puffy Jupiters." The lightest planet ever discovered is the superpuffy Kepler 51d, which is nearly 🏧 the size of Jupiter but a hundred times lighter than the gas giant.
Puffy Jupiters have largely been a mystery for 🏧 15 years, said lead study author Khalid Barkaoui. But WASP-193b, because of 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's difficult to think of 🏧 an analogous, solid-state material," said Barkaoui, a postdoctoral researcher of Earth, atmospheric and planetary sciences at the Massachusetts Institute of 🏧 Technology, in a news release. "The reason why it's close to cotton candy is because both are mostly made of 🏧 light gases rather than solids. The planet is basically super fluffy."
WASP-193b, which researchers think is made up of mostly hydrogen 🏧 and helium, was a huge puzzle for researchers to piece together. Because the exoplanet's density is so light for its 🏧 size, calculating its mass became a challenge.
Desafio calcular a massa do planeta
Usually, scientists determine mass using a technique called 🏧 radial velocity, in which researchers analyze how a star's spectrum, a graph that indicates the intensity of light emissions in 🏧 wavelengths, shifts as a planet orbits it. The bigger the planet, the more the star's spectrum can shift - but 🏧 this didn't work for WASP-193b, which is so light, it didn't make any pull on the star that the team 🏧 could detect.
Because of how small the mass signal was, it took the team four years to gather data and calculate 🏧 WASP-193b's mass, Barkaoui explained. Because the extremely low numbers they found were so rare, the researchers completed multiple trials of 🏧 data analysis, just to be sure.
"We were initially getting extremely low densities, which were very difficult to believe in the 🏧 beginning," said co-lead author Francisco Pozuelos, a senior researcher at Spain's Institute of Astrophysics of Andalucia, in a news release.
Eventually 🏧 the team discovered the planet's mass is a measly 14% that of Jupiter, despite being so much bigger.
Um planeta com 🏧 uma atmosfera ext ```python endedora
But a bigger size means a bigger "extended atmosphere," said study coauthor Julien de Wit, an associate professor 🏧 of planetary science at MIT. That means WASP-193b provides an especially useful window into these puffy planets' formation.
"The bigger a 🏧 planet's atmosphere, the more light can go through," de Wit told . "So it's clear that this planet 🏧 is one of the best targets we have for studying atmospheric effects. It will be a Rosetta Stone to try 🏧 and resolve the mystery of puffy Jupiters."
But it's also not clear how WASP-193b even formed, Barkaoui said. The "classical evolution 🏧 models" of gas giants don't quite explain the phenomenon.
"WASP-193b is an outlier of all planets discovered to date," he said.
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