The view from K2: questioning the traditional view of flaring on early dM stars

Abstract

We use K2 short cadence data obtained over a duration of 50 d during Campaign 0 to observe two M1V dwarf stars, TYC 1330-879-1 and RXJ 0626+2349. We provide an overview of our data analysis, in particular, making a comparison between using a fixed set of pixels and an aperture which follows the position of the source. We find that this moving aperture approach can give fewer non-astrophysical features compared to a fixed aperture. Both sources shows flares as energetic as observed from several M4V stars using both Kepler and ground-based telescopes. We find that the flare energy distribution of the sources shown here are very similar to the less active M3-M5 stars but are ∼8 times less likely to produce a flare of a comparable energy to the more active M0-M5 stars. We discuss the biases and sources of systematic errors when comparing the activity of stars derived from different instruments. We conclude that K2 observations will provide an excellent opportunity to perform a census of flare activity across the full range of M dwarf spectral class and hence the physical mechanisms which power them.