Rate of mass loss rate by long-period variables

The dependence of the mass loss rate of a red giant long-period variable on the rate of dust condensation in the circumstellar shell is investigated for the case of steady mass loss. A stellar mass of 2 solar masses, a luminosity of 6 x 10 to the 37th erg/s, and a radiation temperature of 2500 K are assumed; the base of the circumstellar shell is taken to be an expanding atmosphere with a radius of 6 x 10 to the 13th cm, a density of 10 to the -13th g/cu cm, and a temperature of 2000 K. It is found that: (1) the stellar mass loss rate depends on the form of the distance dependence of the absorption factor and on the difference between the distance at which the gas acceleration due to radiation pressure balances the gravitational acceleration and the distance that corresponds to a temperature of 1200 K; (2) the primary governing factor for the mass loss rate is the distance from the level in the shell where dust condensation begins; and (3) this distance should not exceed 10 to the 13th cm for a mass loss rate of 1 millionth of a solar mass per yr.