ON THE MASS EJECTION AND THERMAL PULSES OF AN AGB STAR WITH AN INITIAL MASS OF 7-M-CIRCLE-DOT

The mechanism driving the episode of large mass loss called superwind from an AGE star with initial mass of 7 M(circle dot) is studied by co mparing the current luminosity of the star with its maximum luminosity set by the balance of several inward and outward acceleration mechani sms (gravity, radiation, rotation, and turbulent forces). The current luminosity during the AGE phase can exceed the maximum luminosity caus ing mass ejection from the AGE star. The periodic variation of the lum inosity is in turn caused by variations in the energy output from the H-burning shelf, which are not related to the thermal pulses of the He -burning shell. The nature of the oscillatory behaviour of the H-burni ng shell is briefly investigated.