Clouds of aluminum and silicates found in the atmosphere of a brown dwarf

Clouds of aluminum and silicates found in the atmosphere of a brown dwarf
Clouds of aluminum and silicates found in the atmosphere of a brown dwarf

Unique observations made it possible to examine the layered and turbulent atmosphere of the planet "super-Jupiter" using the example of a neighboring brown dwarf.

Brown dwarf 2MASS J22081363 + 2921215: artist's view

The gas giant Beta Painter b is one of the most studied exoplanets, even photographed directly. It is located 63 light years from us, has a mass seven times the mass of Jupiter and 1.65 times the diameter. Beta Painter b is referred to as "super-Jupiters" - planets that can gain mass at times, and sometimes tens of times greater than that of Jupiter.

In many respects, "super-Jupiters" are close to brown dwarfs, which, in turn, occupy an intermediate position between planets and stars. However, "super-Jupiters" are closely related to their stars and are eclipsed by their light, and brown dwarfs are independent. Therefore, to study the atmosphere of Beta Painter b, astronomers decided to consider the brown dwarf 2MASS J22081363 + 2921215, similar to the planet in size and temperature, but free-flying. In addition, both the dwarf and Beta Painter b are included in the group of young stars closest to us, united by a common movement and, apparently, by origin.


Ground-based telescopes are not very suitable for such observations, since some of the important infrared waves are absorbed as they pass through the earth's atmosphere. Therefore, the scientists used the Keck Observatory MOSFIRE spectrograph, which covers a relatively large field of view. Thanks to this, stars fell into it along with the brown dwarf. Elena Manjavacas and her colleagues write about this in an article that has been accepted for publication in The Astronomical Journal and is available in the online preprint library.

By comparing their spectrum, which passed through the atmosphere, with the previously established "initial" spectrum, scientists were able to figure out which lines and how exactly were absorbed in the air. And this, in turn, made it possible to reconstruct the "original" spectrum of the brown dwarf and examine its atmosphere. At 12 times the size of Jupiter, it turned out to be quite hot: the temperature was estimated at 1500 ° C. In addition, the brown dwarf rotates rapidly, making a full revolution every three and a half hours, so that powerful turbulent vortices do not subside in the atmosphere.

For two and a half hours of observations, the MOSFIRE instrument also examined individual moving light areas in it - all this suggests that the atmosphere is filled with clouds through which the infrared radiation of the hot dwarf breaks through. At high altitude, these clouds contain potassium iodide and magnesium silicate, lower potassium is replaced by sodium, and even further, at a depth, clouds of aluminum oxide appear. The total depth of the atmosphere is estimated at 718 kilometers; Beta the Painter b is supposed to have a similar structure.

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