Dynamics of flares on late-type dMe stars. I. Flare mass ejections and stellar evolution.

Evidence of a high-velocity mass ejection event starting with the onset of a particularly violent flare on the M dwarf star AD Leo is presented and discussed. The plasma was ejected at projected line-of-sight speeds of up to 5800 km/s. The velocity, mass, and kinetic energy of the flow are compared to solar Coronal Mass Ejection (CME) events. The recent and independent discovery of a strong stellar wind, probably driven by sporadic CME events on V471 Tauri, is strongly in favor of the present interpretation. An estimation of the ejected mass during the observed flare event for various sets of electron temperature and plasma opacity effects, combined with mean flare occurrence rates, indicates that flare related mass loss may significantly affect the normal evolution of active red-dwarfs.