Fluffy ‘marshmallow’ world discovered with incredibly low density

(ORDO NEWS) — If exoplanet research is to be believed, the Milky Way galaxy could be something of a fantasy land of candy.

First, exoplanets with the density of cotton candy have been discovered. Astronomers say they have discovered a world whose density is comparable to that of a marshmallow. They say it’s the fluffiest exoplanet discovered to date, orbiting a red dwarf.

It is important. This means that it is possible to find worlds with significant gas envelopes orbiting small, stormy dwarf stars, which astronomers previously suspected could deprive any closely orbiting planets of much of their atmospheres.

Since atmospheres are believed to exist to be one of the key planetary features that allow life to form and flourish, this will have implications for our understanding of the habitability of planets orbiting red dwarfs.

“Giant planets around red dwarfs are traditionally considered difficult to form,” says planetary scientist Shabham Kanodia of the Carnegie Institution’s Earth and Planetary Laboratory.

“Until now, it has only been considered with small samples from Doppler studies that giant planets are farther away from these red dwarfs. Until now, we didn’t have a large enough sample of planets to reliably find nearby gas planets.”

Red dwarfs are by far the most numerous stars in the Milky Way. They are very small, cold and dim – so dim that none of them can be seen with the naked eye, despite the fact that they make up about 73 percent of all the stars in the Milky Way.

Because they are small, they burn more slowly and are less hot than stars like our Sun, meaning they have a significantly longer lifespan. The lifespan of our Sun is estimated at about 10 billion years.

Red dwarfs are expected to live for trillions of years. This longevity, combined with the abundance of red dwarfs, means that life, if it does appear somewhere, could appear on a planet orbiting a red dwarf star.

But red dwarfs can be very, very moody. , also whipping the space around them with powerful flares that can irradiate and sterilize any exoplanets in close orbit and deprive them of their atmosphere.

And because these stars are so cold for an exoplanet to have a temperature favorable to life as we know it, that planet must be within range of the flares. So, you know, this is a problem.

But perhaps this is not how this new world suggests. Called TOI-3757b, it is a gas giant orbiting a red dwarf star in the constellation Auriga, about 580 light-years away.

TOI-3757b was discovered by the TESS Space Telescope, which finds exoplanets. by detecting regular dips in light caused by a planet passing in front of a star. If you know how bright a star is, then how much light is blocked will tell you how big an exoplanet is. From this we know that TOI-3757b is slightly larger than Jupiter.

Then, to get the exoplanet’s mass, the researchers looked for changes in the star’s light that indicate the gravitational pull exerted on it by the exoplanet. Since gravity is related to mass, this gave us a mass of about 85 Earth masses.

Jupiter, based on the context, has a mass of about 318 Earth masses with an average density of 1.33 grams per cubic centimeter. The average density of TOI-3757b is 0.27 grams per cubic centimeter. This is a very fluffy exoplanet – so fluffy that it is not clear how it could form so close to its star: it completes one revolution in 3.43 days.

Kanodia and his colleagues believe that two factors may be at play here. . First, gas giants form with a rocky core, around which gas accumulates, forming a dense extended atmosphere.

Since the red dwarf has few heavy elements compared to other gas giant red dwarfs, it is possible that the rocky core formed slightly more slowly, which delayed the accumulation of gas and affected the density of the world.

Second, the orbit appears to be slightly oval, which means its distance from the star varies. Perhaps as it approaches, the atmosphere heats up and expands.

Other astronomers have suggested that puffy exoplanets may have extended ring systems like Saturn; but Kanodia and other researchers have found that TOI-3757b is too close to its star to maintain a stable ring system. So it’s probably just a very bloated atmosphere.

The team hopes to find and study other similar marshmallow worlds to help understand how they form and survive in a place that should be difficult for them to do so.

“Finding more such systems with giant planets, once thought to be extremely rare around red dwarfs, is part of our goal to understand how planets form,” Kanodia says.


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