The Internal Structure of Red Dwarf Stars.

Models are computed for red dwarf stars, with the hydrogen convection zone taken into account. The calculations show that in red dwarfs this outer convection zone extends inward for a distance of about 30 per cent of the radius of the star. The central temperatures of these models are found to be much lower than the central temperatures of models computed under the assumption of radiative equilbrium throughout the star. Thus the earlier difficulty of an overproduction of energy by the proton-proton reaction does not appear in these models. The observed luminosities, masses, and radii of red dwarf stars such as Castor C and a Cen B can be understood in terms of these models and lead to normal abundances of the elements. For very late-type dwarfs, such as Kr 60 A, other physical effects appear to become important, and the models of the present paper probably are no longer applicable.