Two physical explanations of the nonextensive parameter in a self-gravitating system

Abstract

In this paper, we present two possible physical explanations of the nonextensive parameter in a self-gravitating gaseous system. One is related to the detailed balance in such system. With the detailed balance, the statistical balance of the molecular energy is reached, under which condition the radiation energy “stored” in the molecules becomes important. Then the relation between the nonextensive parameter and the storage coefficient, which measures the ability of the molecules to store the radiation energy, is constructed. Another explanation is originated from one dimensionless quantity called (logarithmic) temperature gradient defined in stellar physics. In view of this, we find that in order to keep the nuclear reaction alive inside the Sun, the ratio of radiation pressure to the total pressure in its core must be greater than 0.2833.