SPECTROSCOPIC SIGNATURES OF MAGNETOSPHERIC ACCRETION IN HERBIG AE/BE STARS

Abstract

Some Herbig Ae/Be stars show spectroscopic signatures indicating that accretion flows in these stars are guided from the circumstellar disk to the stellar surface by a magnetic field inside their magnetospheres. We consider three objects with such signatures. All of them can be divided into three groups: a) rotational modulation of spectral parameters originating near accretion region. These are the profiles of the infrared lines HeI 10830 and Pa (the case of HD101412) and the lines HeI 5876 and Hb in the visual spectral region (HD259431); b) cyclic variability of the HeI 5876 line profile when its red absorption component becomes strongly extended up to +400 km/s once during a rotation period (HD259431, HD37806); and c) fast variability of the red absorption component of the HeI 5876 line profile (during one night) in the form of standing intensity wavws. We can prove
that all these phenomena can be observed only if the local accretion flows are rotating rigidly with the magnetic field of the star inside the magnetosphere.