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arXiv · 2310.18017

Some properties of plasma surrounding brown dwarfs

Dmitry Kobyakov
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Abstract

Recently, brown dwarfs have emerged as a new topic for the astrophysical studies. These objects are intermediate between solar-type stars and giant gaseous planets. In this article, the analogies between brown dwarfs and the planet Jupiter are considered with a focus on the surrounding plasma. I consider the magnetohydrodynamic version of the Rayleigh-Taylor instability (or so called ``interchange instability'') as a minimal model of the expansion of the plasma disc surrounding Jupiter. By comparing the theoretical prediction for the radial expansion rate of the disc with the observations I quantitatively confirm the existing qualitative result, which predicts that the Rayleigh-Taylor instability provides too quick expansion. Therefore, in the realistic plasma disc yet another mechanism must operate which slows down the expansion. I suggest that similar mechanisms take place in the observed radiation belts of brown dwarfs.

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Dmitry Kobyakov. 2023-10-27. Some properties of plasma surrounding brown dwarfs. https://doi.org/10.31725/0552-5829-2023-167-170

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