Detection of Flare-associated CME Candidates on Two M-dwarfs by GWAC and Fast, Time-resolved Spectroscopic Follow-ups

2021/06/09 by J. Wang, L. P. Xin, H. L. Li +8
Physics and Astronomy · #astro-ph.SR

paper · pdf · doi:10.3847/1538-4357/ac096f

15 pages, 10 figures and 5 tables, accepted by ApJ

arxiv created 2021/06/09 · arxiv updated 2021/08/11

Abstract

The flare-associated stellar coronal mass ejection (CME) in solar-like and late type stars is quite essential for the habitability of an exoplanet. In this paper, we report detection of flare-associated CMEs in two M-dwarfs, thanks to the high cadence survey carried out by the Ground Wide-angle Camera system and the fast photometric and spectroscopic follow-ups. The flare energy in R-band is determined to be 1.6×10³⁵ erg and 8.1×10³³ erg based on the modeling of their light curves. The time-resolved spectroscopyic observations start at about 20 and 40 minutes after the trigger in both cases. The large projected maximum velocity of ∼500-700 \mathrmkm s^-1 suggests that the high velocity wing of their Hα emission lines are most likely resulted from a CME event in both stars, after excluding the possibility of chromospheric evaporation and coronal rain. The masses of the CMEs are estimated to be 1.5-4.5×10¹⁹ g and 7.1×10¹⁸ g.

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