A subject of intense current interest in astronomy is mass loss from stars. Mass loss occurs during virtually all phases of stellar evolution, though the rate of mass loss varies considerably. One of the more enigmatic phases of mass loss occurs during the red giant phase of stars that have masses similar to that of the sun. These stars may shed up to 10-3 solar masses per year and thereby produce planetary nebulae (which are circumstellar gaseous shells that expand at speeds of a few km/sec). The mass loss regions surrounding some of the most luminous red giants are characterized by strong hydroxyl maser emission. The Principal Investigator (PI) proposes to investigate theoretically and observationally such regions. The objective of the research is to understand better the mass shedding process; to describe in greater detail the geometric, dynamic, thermodynamic, and magnetic structure of the mass loss regions; and to determine the collective influence of this mass loss on the chemical evolution of the galaxy.
