ИСТИНА

Brown dwarfs are substellar objects that occupy an intermediate position between stars and planets. Their masses range from approximately ~13 to ~80 MJ, where MJ = 1.9×10²⁷ kg is the mass of Jupiter. The upper limit (80 MJ) corresponds to the mass at which thermonuclear hydrogen burning begins in the object's core, while the lower limit (13 MJ) is the minimum mass required for deuterium burning inside the celestial body. The goal of this work is to give an answer to the question: Why does one of two nearly identical isolated ultracold brown dwarfs exhibit auroras and a temperature inversion with altitude in its atmosphere, while the other does not? We suggest that the possible reason lies in the fact that one brown dwarf (W1935) possesses a magnetic field and a surrounding plasma magnetodisk. When the magnetic dwarf rotates rapidly, its interaction with the magnetodisk may produce the observed phenomena. If the second brown dwarf (W2220) lacks its own magnetic field and/or a magnetodisk, it does not meet the necessary conditions for generating auroras and temperature inversion with altitude in its atmosphere. We demonstrate how these phenomena depend on the brown dwarf's characteristics and the parameters of the circum-substellar plasma disk. Additionally, this work focuses on comparing brown dwarfs with stellar red dwarfs and giant planets.