Origin of the Blue Continuum Radiation in the Flare Spectra of dMe Stars

Abstract

Calculations of the emission spectrum of a homogeneous plane layer of pure hydrogen plasma taking into account nonlinear effects (the influence of bremsstrahlung and recombination radiation of the layer itself on its Menzel factors) [Morchenko et al., Ap&SS, Vol. 357, article id. 119 (2015)] show that the blue component of the optical continuum during the impulsive phase of large flares on dMe stars originates from the near-photospheric layers [Grinin and Sobolev, Afz, Vol. 13, 587 (1977)]. The gas behind the front of a stationary radiative shock wave propagating in the red dwarf chromosphere toward the photosphere is not capable of generating the blackbody radiation observed at the maximum brightness of the flares.