H-alpha as a tracer of mass loss from OB stars

Abstract

view Abstract Citations (167) References (35) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS H alpha as a Tracer of Mass Loss from OB Stars Leitherer, Claus Abstract This paper investigates the use of the H-alpha emission from stellar winds of OB stars to determine the stellar mass-loss rate. The power in H-alpha emitted by the wind can be parameterized in terms of the temperature and the density field of the wind. A simple expression is derived which relates the observed H-alpha luminosity to the stellar mass-loss rate, the stellar radius, the velocity law, and the stellar effective temperature. This expression is calibrated for the influence of the velocity law using a sample of Galactic OB stars with UV mass-loss rates. Consequently, the results depend on the validity of the UV rates. The derived velocity law for O stars turns out to be in agreement with the radiation-pressure-driven wind theory. There is evidence for a dependence of the velocity-law gradient on spectral type. The results for B stars, however, are more uncertain due to the dependence on the adopted mass accretion rate/L relation. Application of the calibrated H-alpha luminosity/mass-loss rate relation to a sample of 149 galactic OB stars shows that mass accretion rate can be reliably determined from H-alpha. Due to the moderate amount of observing time required to derive mass accretion rate from H-alpha, this method may be applied successfully to investigate mass-loss effects in extra-Galactic stars. Publication: The Astrophysical Journal Pub Date: March 1988 DOI: 10.1086/166097 Bibcode: 1988ApJ...326..356L Keywords: B Stars; Early Stars; H Alpha Line; O Stars; Stellar Mass Ejection; Stellar Winds; Ultraviolet Radiation; Astrophysics; LINE PROFILES; STARS: EARLY-TYPE; STARS: MASS LOSS full text sources ADS | data products SIMBAD (149)