Coronae of cool stars

With the hypothesis generally adopted as responsible for the heating of the solar corona an attempt was made to predict the coronal temperature for a few cool stars.Stars with effective temperatures between 2500K and 3700K, with logg-values of 3 or 4, appear to have coronal temperatures only 600 to 25000K higher thanT _eff.In order to determine the possibility of coronal heating caused by sound waves we made a comparison between the frequency of the sound waves and the cut-off frequencies.