BEAT FREQUENCY-MODULATION OF T-TAURI ACCRETION RATES

A general model of magnetically controlled accretion on to T Tauri stars is presented. In this model the magnetic field is oriented arbitrarily in relation to the star's rotation axis. The resultant interplay between the magnetic field and accretion disc causes a variable accretion rate. The dominant time-scale of this variability is the beat frequency between the stellar rotation frequency and the orbital frequency at the magnetosphere boundary. This model is analogous to that developed to explain quasi-periodic oscillations in low-mass X-ray binaries.