Characteristics of activity energetics of the UV cet-type flare stars

Abstract

A quantitative comparison of energetics of different manifestations of the activity of the UV Cet-type flare stars — sporadic flares, quiet chromospheres and coronae and stellar spots — have been carried out. On the basis of a statistical analysis of about 1800 flares registered for 23 flare stars, the energy spectra of flares have been constructed and time-averaged powers of optical radiation of flares —L _flares — have been estimated. By use of spectroscopic observations of 26 flare stars between flares, the total radiation in Balmer lines of quiet chromospheres —L _Bal — have been found. On the basis of these data and the soft X-ray observations of 29 flare stars, the mean of the ratiosL _flares/L _bol,L _Bal/L _bol andL _X /L _bol have been found to be equal to (1–2)×10⁻⁴. By use of photometric observations for 9 stars, the total starspot radiation deficits —L _spots — have been estimated as (4×10⁻³−6×10⁻²)×L _bol. Discussions of probable underestimates in the valuesL _flares,L _Bal,L _X , andL _spots leads to the conclusion that the total power of non-equilibrium processes that take place in flare star atmospheres is close to the total starspot radiation deficit in these stars.