Time-Resolved Properties of the White Light Continuum During Stellar Flares/ Seminar Series (4)

Speaker:Adam Kowalski
Affiliation:
Astronomy Department, University of Washington
Title: Time-Resolved Properties of the White Light Continuum During Stellar Flares
Date: 17 February  2011
Place: ING+NOT Astro-seminar- Santa Cruz-La Palma- Spain

Abstract:
The primary mode of radiative energy release in stellar flares is in the optical and near-ultraviolet (NUV) continuum. This white light radiation carries a large fraction of the total radiated flare energy. However, radiative hydrodynamic models of stellar flares using a solar flare paradigm and the sparse observations of solar and stellar flare continua are all seemingly in disagreement over the type(s) of emission that contribute to the optical/NUV continuum during flares. We have begun a long-term spectroscopic flare monitoring campaign to fully characterize the  optical/NUV white light continuum emission on short timescales for large and  small flares. To date, our most significant results come from spectroscopic (3350A - 9260A) and photometric (U band) observations during  1.3 hours of the decay phase of a megaflare on the dM4.5e star YZ CMi, where  we have detected multiple continuum components that contribute to the white  light. I will present the continuum and emission line properties of this  flare and initial phenomenological modeling of the flaring atmosphere. I will  also compare the continuum properties to ultra-high speed observations of 
smaller flares