On the global electrostatic charge of stars
Queen Mary and Westfield College, Mile End Road, London E1 4NS, UK
Accepted: 6 April 2001
As was discovered in the nineteen-twenties, a significant electric field exists in the solar corona as well as in the solar interior. This field is a consequence of the tendency of light electrons to segregate from heavier protons in the solar gravitational field. Since the principle is valid for a plasma in every star, the result can be generalized. The presented paper is intended to rehighlight this significant physical property of stars. In particular, we stress that there has to be charge Qr inside a stellar sphere with radius r, which is linearly proportional to mass Mr inside the sphere. Both quantities are related as , if Qr is given in Coulombs and Mr in solar masses. The global stellar electrostatic field is 918 times stronger than the corresponding stellar gravity and compensates for a half of the gravity, when it acts on an electron or proton, respectively. The external electric field has to cause an occurence of electric current and appropriate magnetic field in a highly conductive plasma, when, e.g., the plasma is in a turbulent motion or spirals onto a star in a hot accretion disc.
Key words: Sun: corona / Sun: fundamental parameters / Sun: particle emission / stars: atmospheres / stars: fundamental parameters
© ESO, 2001