Mass loss from evolved stars. VII - OH maser shell radii and mass-loss rates for OH/IR stars

Abstract

view Abstract Citations (107) References (33) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Mass Loss from Evolved Stars. VII. OH Maser Shell Radii and Mass-Loss Rates for OH/IR Stars Netzer, Nathan ; Knapp, G. R. Abstract The equations of photodissociation and radiative transfer are solved for the photochemical chain H2O yields OH + H yields O + H + H in the circumstellar envelopes produced by steady mass loss from cool evolved stars. The solution is performed for a large range of mass-loss rates, outflow velocities, and interstellar UV radiation field densities. Comparison with observations shows that, over a wide range of mass-loss rates, the radius at which the OH density peaks coincides with the radius defined by maser emission in the 1612 MHz line. This allows the use of these models, together with observations of OH maser shell radii and wind outflow velocities, to measure mass-loss rates. A simple power-law function relating mass-loss rate to OH shell radius and wind outflow velocity is developed from these models and is applied to the existing measurements of OH shell radii to derive mass-loss rates for 42 stars. Publication: The Astrophysical Journal Pub Date: December 1987 DOI: 10.1086/165867 Bibcode: 1987ApJ...323..734N Keywords: Interstellar Masers; Photodissociation; Stellar Envelopes; Stellar Evolution; Stellar Mass Ejection; Cool Stars; Hydroxyl Emission; Late Stars; Stellar Models; Stellar Winds; Astrophysics; MASERS; RADIATIVE TRANSFER; STARS: CIRCUMSTELLAR SHELLS; STARS: LATE-TYPE; STARS: MASS LOSS full text sources ADS | data products SIMBAD (53) Related Materials (7) Part 1: 1982ApJ...252..616K Part 2: 1983ApJ...275..330S Part 3: 1985ApJ...292..640K Part 4: 1986ApJ...303..521K Part 5: 1985ApJ...293..273K Part 6: 1985ApJ...293..281K Part 7: 1986ApJ...311..731K