Flares at the cool end of the M dwarfs: The case of LHS 2065

LHS 2065 is an M9 very low mass star at a distance of 8.5 pc. It was known to have Ha emission, but no other emission lines had been seen before. We o bserved it on 1998 December 12 and found a rich emission spectrum (He I, Na D, and Balmer series). Additional spectra were obtained after 1 hr, 2 hr, and 1 day. They showed progressively weaker emission lines. Using our data and a compilation of the literature, we find that, while strong flares in L HS 2065 are rare (their recurrence rate is less than or equal to0.03 hr(-1) ), weak flares may be common (about 0.5 hr(-1)). Our observations add to th e growing evidence that many, if not all, of the coolest M dwarfs have flar e activity.