Influence of red dwarf component activity on accretion in close binary systems

Abstract

Abstract Active late type stars lose mass as due to the effect of magnetic instabilities in their corona connected to flares. The phenomenon is similar to what happens in the Sun, but with greates intensity, with the stellar wind reaching M ∼ 10−11 Mθ yr−1. In later spectral types the effect is suspected to be more discontinuous and dominated by coronal mass ejections (CMEs): transient events of gas expulsion due to large-scale reconnection of the magnetic field. CMEs from active red dwarfs have been detected in the last few years. In these transient events up to 1016 g of gas are expelled on time-scales of some minutes. Some observations suggest that such events can support a mass loss rate from the active star M ∼ 10−11 Mθ yr−1, similar to the above case. We investigate the possibility that interaction between the expelled gas and the accretion pattern around the compact object in Cataclysmic variables (CVs) and low-mass X-ray binaries (LMXBs) gives rise to observable energy release. We estimate that in...