March 29, 2024

Astronomers Find a “Marshmallow World”: the Lowest Density Gas Giant Ever Discovered

Recently, the WIYN telescope on Kitt Peak in Arizona did a follow-up observation of a gas giant found by TESS (the Transiting Exoplanet Survey Satellite). The world is weird and fluffy and its orbiting a red giant star. There it is gladly orbiting a star some 580 light-years from Earth.

The gas giant planet in question is called TOI-3757 b. Based on measurements by WIYN and TESS, as well as other telescopes, TOI-3757 bs average density turns out to be 0.27 grams per cubic centimeter. Such a puffy characteristic is hard to believe, particularly considering that the star it orbits isnt precisely the best place to host gas giants.
” Giant worlds around red dwarf stars have traditionally been believed to be tough to form,” states Shubham Kanodia, a scientist at Carnegie Institution for Sciences Earth and Planets Laboratory and first author on a paper published in The Astronomical Journal about TOI-3757 b. “So far this has actually just been looked at with small samples from Doppler studies, which usually have discovered giant planets further away from these red dwarf stars. Until now we have not had a big enough sample of planets to find close-in gas worlds in a robust way.”

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How a Red Dwarf Threatens a Gas Giant
Why are red dwarf star systems not-so-optimal habitats for fluffy giant planets? Theyre definitely cooler than their better, bigger counterparts in the star household. These little stars can be active, too.
Its possible the extra-low density of TOI-3757 b might date back to the formation of its interior. Usually, gas giants are born with rocky cores that can be approximately about ten times the mass of Earth. Their gravity draws in huge amounts of gas from the protoplanetary nebula. Thats how you get Jupiters and Saturns (for example). Its likely this didnt happen with TOI-3757 b. Its red dwarf star isnt really rich in heavy elements compared to other M-dwarfs with gas giants. Thats a crucial clue. It indicates the planets rocky core formed more gradually. Since it took longer to gather adequate rocky materials from the nebula, thats. If thats true, then the planet didnt accrete rather as much gas throughout its development, which impacted the planets total density.
Theres a 2nd clue that might describe the marshmallow planet. Its elliptical orbit takes it closer to the star at particular times. That heats the environment more than regular and triggers it to puff up.
Exploring the Marshmallow
Of course, theres a lot more to learn about this world and astronomers are distressed to study it in more information. “Potential future observations of the atmosphere of this planet using NASAs brand-new James Webb Space Telescope could help clarify its puffy nature,” said Jessica Libby-Roberts, a postdoctoral researcher at Pennsylvania State University.
This is especially true given that discovering even one such planet around a red dwarf indicates there are most likely more of them out there. In the grand scheme of exoplanet research studies, understanding a puffy Jupiter orbiting an active cool star will offer astronomers more insight into how planets form around several kinds of stars.
For More Information
Marshmallow World Orbiting a Cool Red Dwarf Star
TOI-3757 b: A Low-density Gas Giant Orbiting a Solar-metallicity M Dwarf
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Such a puffy attribute is hard to believe, specifically because the star it orbits isnt exactly the best location to host gas giants.
Why are red dwarf star systems not-so-optimal habitats for fluffy giant worlds? Its likely this didnt happen with TOI-3757 b. Its red dwarf star isnt really rich in heavy elements compared to other M-dwarfs with gas giants.

The world is fluffy and weird and its orbiting a red giant star. There it is gladly orbiting a star some 580 light-years from Earth.