Our galaxy seems to be a very sweet place . At least, as far as sugary comparisons by astronomers are concerned. First, we found the cotton candy planet and now, scientists claim to have discovered a world with a density equal to a cloud of sugar. It is the fluffiest exoplanet discovered to date.
Detected by TESS, the planet hunter
The planet in question is orbiting a cool red dwarf 580 light-years away from Earth, in the constellation Auriga. Red dwarfs are small, dim stars that are still converting hydrogen to helium in their cores through nuclear fusion, a stage in a star’s life that astronomers call “main sequence.” They are the most numerous stars in the Milky Way; they make up about 73% of all the stars in our galaxy.
Although at this stage they are cooler than the Sun, they are very active and launch powerful eruptions that can destroy the atmospheres of any planet in orbit. In this case, the newly discovered world, which has been dubbed TOI-3757 b , is so close to its star that it completes an orbit in just 3.5 Earth days, 25 times faster than Mercury.
“Giant planets around red dwarf stars have traditionally been thought to be difficult to form,” explains Shubham Kanodia, a planetary astronomer at the Carnegie Institution for Science’s Earth and Planets Laboratory in his study published in The Astronomical Journal. “Until now, this has only been analyzed with small samples from Doppler surveys, which have generally found giant planets further away from these red dwarf stars. Until now, we haven’t had a large enough sample of planets to find nearby gas planets in a robust way.
How did this exoplanet form?
Astronomers believe that they can explain how a low-density gas giant formed under such unfavorable and extreme conditions thanks to two main factors: the first relates to how gas giants begin their formation, with rocky cores about 10 times more massive. the mass of Earth, drawing in large amounts of surrounding gas to become Jupiter-like worlds; the lower abundance of heavy elements in the star would suggest that the planet’s core formed more slowly, which, in turn, would have had a major effect on the overall density of the planet after its formation. The orbit also appears to be slightly oval, which means that its distance from the star varies. Perhaps when it gets closer, the atmosphere heats up and expands.
We know that TOI-3757b is slightly larger than Jupiter, because if we know how bright the star is, how much light is blocked tells us how big the exoplanet is. Jupiter, for context, has a mass of about 318 Earths, with an average density of 1.33 grams per cubic centimeter. The average density of TOI-3757b is 0.27 grams per cubic centimeter. It is very fluffy.
The team hopes to find and study other similar fluffy worlds, to help figure out how they form and survive in a place where it should be difficult for them to do so.
“Finding more such systems with giant planets, once theorized to be extremely rare around red dwarfs, is part of our goal of understanding how planets form ,” the researchers conclude.
Referencia: Shubham Kanodia, Jessica Libby-Roberts, Caleb I. Cañas, Joe P. Ninan, Suvrath Mahadevan, Gudmundur Stefansson, Andrea S. J. Lin, Sinclaire Jones, Andrew Monson, Brock A. Parker, Henry A. Kobulnicky, Tera N. Swaby, Luke Powers, Corey Beard, Chad F. Bender, Cullen H. Blake, William D. Cochran, Jiayin Dong, Scott A. Diddams, Connor Fredrick, Arvind F. Gupta, Samuel Halverson, Fred Hearty, Sarah E. Logsdon, Andrew J. Metcalf, Michael W. McElwain, Caroline Morley, Jayadev Rajagopal, Lawrence W. Ramsey, Paul Robertson, Arpita Roy, Christian Schwab, Ryan C. Terrien, John Wisniewski, and Jason T. Wright. TOI-3757 b: A Low-density Gas Giant Orbiting a Solar-metallicity M Dwarf. The Astronomical Journal, Volume 164, Number 3 DOI: DOI: 10.3847/1538-3881/ac7c20