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Metallicity Dependence of Winds from Red SuperGiants and Asymptotic Giant Branch Stars. Jacco van Loon Keele University. Jacco van Loon Keele University. Dust wind structure. Radiative equilibrium + continuity equation:. Spectral Energy Distribution. Spectral Energy Distribution.
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Metallicity Dependence of Winds from Red SuperGiants and Asymptotic Giant Branch Stars
Dust wind structure Radiative equilibrium + continuity equation:
Spectral Energy Distribution • Integral luminosity
Spectral Energy Distribution • Integral luminosity • Shape optical depth
Spectral Energy Distribution • Integral luminosity • Shape optical depth … but measuring mass-loss rate requires: • Dust-to-gas ratio
Spectral Energy Distribution • Integral luminosity • Shape optical depth … but measuring mass-loss rate requires: • Dust-to-gas ratio • Wind speed
Dust wind structure Momentum equation: Gail & Sedlmayr (1986)
Wind speed from OH masers Wood et al. (1992)
Wind speed For oxygen-rich stars
LMC versus the Milky Way Van Loon (2000)
Mass-loss rate For oxygen-rich stars
Superwind mass-loss rates Conversion of radiative momentum:
Superwind mass-loss rates Conversion of radiative momentum: Multiplescattering: Gail & Sedlmayr (1986)
Superwind mass-loss rates Multiple scattering limit predicts:
Superwind mass-loss rates Multiple scattering limit predicts:
LMC versus galactic bulge Alard et al. (2001)
Temperature and evolution Galactic bulge observations: Alard et al. (2001)
Temperature and evolution Galactic bulge observations: Alard et al. (2001) Hydrodynamic models (carbon stars): Arndt, Fleischer & Sedlmayr (1997) Wachter et al. (2002)
Superwind stars in the LMC Cluster superwind carbon star LI-LMC 1813: luminosity, metallicity (20-25% solar), mass Van Loon et al. (2003)
Superwind stars in the LMC Cluster superwind carbon star LI-LMC 1813: luminosity, metallicity (20-25% solar), mass Van Loon et al. (2003) Compare with solar metallicity model: Wachter et al. (2002)
Superwind stars in the LMC Van Loon et al. (2005)