Author(s): , ,
Institution(s): 1. University of Colorado
All flares are not created equal. In particular, flares on low-mass stars are notable for their diversity, even between events on the same star. To better characterize these differences and the range of flare morphologies possible on low-mass stars, we analyzed a sample of such flares in detail using temporally resolved UV spectroscopy from the growing body of MUSCLES Treasury Survey data. Specifically, we used the data to analyze the response of several UV emission lines (e.g. C II, Si III, Si IV) and the UV continuum following each impulsive event. From this analysis, we present a qualitative picture of energy deposition and propagation in the stellar atmosphere during a few representative events. These data also permitted a spectral comparison with flares typical of the Sun, and we describe the most prominent differences that emerged from this comparison. Additionally, by including flares from all the observed MUSCLES stars, we create an energy-frequency plot for flares on “quiescent” M-dwarfs and compare it to that of the Sun and of well-studied “active” M-dwarfs such as AD Leo. Flares like those we detected and analyzed can strip some atmosphere from closely orbiting planets, adversely affecting the long-term habitability of planets that might have initially supported liquid surface water. To gauge the amplitude of this effect, we used the flare data to make an empirically driven estimate of how much mass each representative flare might remove from the atmosphere of an Earth-like planet.