A hypothesis of the hydromagnetic activity of T Tau-type stars and related objects

A hypothesis on the hydromagnetic nature of T Tau-type stellar activity that suggests a way of solving the main energetic problem of these stars is given in detail. In this model it is supposed that the whole surface of a T Tau-star is covered with structures similar to sunspots, and that the deficit of radiation from these dark spots is carried away by hydromagnetic waves. The assumptions on which the hypothesis rests are shown to be consistent with existing astrophysical and stellar evolutionary ideas. Several consequences of the hypothesis concerning the physical and evolutionary problems of T Tau-stars, FU Ori-type stars, magnetic, antiflare and classical flare star are discussed. Possibilities of testing the hypothesis observationally are considered. (author)