The influence of convection and rotation on X-ray emission in main sequence stars.

In view of establishing the dependence of X-ray luminosity L_X or flux F_X with global stellar parameters, the authors analyze a sample of 44 main sequence stars observed by the Einstein Observatory and for which data are published in the literature. It is first suggested that the convection-rotation interaction can be represented by an effective Rossby number Ro^*. It is given by 1/2(v_m/ΩL_c), where v_m is the maximum convective velocity, Ω the rotation rate and L_c the total depth of the convective zone. Relations are presented first between L_X and Ro^*-1.2, then between F_X and Ro^*-3.3. These results are compared to those empirically obtained by other authors between the K line luminosity or the X-ray flux and Ω. The relations obtained support the hypothesis of a common mechanism to generate coronal emission in main sequence stars.