Formation of Hydrogen Emission Lines in the Magnetospheres of Young Stars

Abstract

The formation of hydrogen emission lines in the magnetospheres of young stars is considered. The magnetosphere is assumed to be formed by a dipolar magnetic field whose axis is aligned with the stellar rotation axis. The radiative transfer in spectral lines is considered in the Sobolev approximation by taking into account the nonlocal radiative coupling. The gas density and temperature distributions in the magnetosphere are taken to be the same as those in Hartmann et al. (1994). The results of our calculations of the Hα and Hβ line intensities and profiles are presented for the case of a slowly rotating star. We separately consider the magnetospheric models in which the infalling gas is heated by radiation from an accretion spot on the stellar surface and the case where the axis of the magnetosphere is tilted with respect to the stellar rotation axis. Rotational modulation of the spectral line profiles with the stellar rotation period is observed in the latter case.