Detection Of Flare-Associated Cme Candidates On Two M-Dwarfs By Gwac And Fast, Time-Resolved Spectroscopic Follow-Ups

The flare-associated stellar coronal mass ejections (CMEs) of solar-like and late-type stars profoundly impact the habitability of any expolanets in the systems. In this paper, we report the detection of flare-associated CMEs for two M-dwarfs, thanks to a high-cadence survey carried out by the Ground Wide-angle Camera system and fast photometric and spectroscopic follow-ups. The flare energies in the R band are determined to be 1.6 x 10(35) erg and 8.1 x 10(33) erg based on modeling of their light curves. The time-resolved spectroscopic observations start at about 20 and 40 minutes after the trigger in both cases. The large projected maximum velocity of similar to 500-700 km s(-1) suggests that the high-velocity wings of their H alpha emission lines most likely result from CME events in both stars, after excluding the possibility of chromospheric evaporation and coronal rain. The masses of the CMEs are estimated to be 1.5-4.5 x 10(19) g and 7.1 x 10(18) g.