Abstract
A. S. Eddington pointed out back in 1926 that stars must have a small positive charge to hold electrons. We propose a model of formation of a double charged layer on the surface of the star. Thermal energy of the star leads to emission of electrons, and strong gravity holds ions and forms a positive charge on the surface of the chromosphere. Increasing the positive charge to a certain value compensates for gravity. This positive charge is shielded by electrons from the coronal plasma, and a double charged layer is formed. The ions are accelerated by the Coulomb field and form a high-temperature corona and a fast solar wind. The star's high coronal temperature, highly charged ions, EUF, X-ray radiation, and solar wind are all caused by the double charged layer on the star's surface. The star's surface charge depends on its mass, spin, temperature, and composition.