Time-resolved NUV And Optical Spectra Of A Stellar Megaflare On YZ CMi With SALT/RSS
American Astronomical Society, AAS Meeting #220, #204.52
Published in May 2012
The primary mode of radiative energy release in stellar flares is in the optical and near-ultraviolet (NUV) continuum. Active M-dwarf stares flare more frequently than the Sun, and their flares can be substantially more energetic. The dominant component in solar flare white light is thought to be Hydrogen recombination, whereas for stellar M dwarf flares, the dominant component is thought to be T 10,000 K blackbody emission. Recently we have obtained very high time-cadence spectral observations of the flaring M-dwarf YZ CMi (3200-6000A) using the Robert Stobie Spectrograph on the 11-meter South African Large Telescope (SALT/RSS), achieving 100x better temporal resolution than has previously been possible at the atmospheric limit. We observed a megaflare of over 100x flux enhancement in the NUV emission. Here we discuss the evolution of the stellar flare spectrum during the rapid impulsive phase of the flare and the implications for stellar flare models.
(c) 2012: American Astronomical Society