[en] According to current models of quasars, their central parts consist of hot and dense interstellar gas and a dense stellar system. Stars moving in those regions will acquire heat flux from the surrounding hot gas, contrary to stars in our galaxy. Evaporation of stellar matter is highly expected from the surface of stars in such circumstances. In the present paper, we calculate numerically the structure and the mass loss rate of stars surrounded by the hot radiation field. The results of our numerical calculations are summarized as follows: i) The structure and mass loss rate are uniquely determined for given temperature of the surrounding radiation field. ii) The time scale of evaporation decreases rapidly as the temperature of the surroundings and is an order of the Kelvin time scale when the temperature of the surroundings is about 100 times as high as their effective surface temperature. On the basis of our results, we further discuss the fate of a star moving in a super massive star. (author)