Metallicity Dependence of Winds from Red SuperGiants and Asymptotic Giant Branch Stars - PowerPoint PPT Presentation

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Metallicity Dependence of Winds from Red SuperGiants and Asymptotic Giant Branch Stars
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Metallicity Dependence of Winds from Red SuperGiants and Asymptotic Giant Branch Stars

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  1. Metallicity Dependence of Winds from Red SuperGiants and Asymptotic Giant Branch Stars

  2. Jacco van LoonKeele University

  3. Jacco van LoonKeele University

  4. Dust wind structure Radiative equilibrium + continuity equation:

  5. Spectral Energy Distribution

  6. Spectral Energy Distribution • Integral luminosity

  7. Spectral Energy Distribution • Integral luminosity • Shape optical depth

  8. Spectral Energy Distribution • Integral luminosity • Shape optical depth … but measuring mass-loss rate requires: • Dust-to-gas ratio

  9. Spectral Energy Distribution • Integral luminosity • Shape optical depth … but measuring mass-loss rate requires: • Dust-to-gas ratio • Wind speed

  10. Dust wind structure Momentum equation: Gail & Sedlmayr (1986)

  11. Dust wind structure

  12. Large Magellanic Cloud

  13. Parkes radio observatory

  14. Wind speed from OH masers Wood et al. (1992)

  15. Marshall et al. (2004)

  16. Wind speed

  17. Wind speed For oxygen-rich stars

  18. LMC versus the Milky Way Van Loon (2000)

  19. Mass-loss rate

  20. Mass-loss rate For oxygen-rich stars

  21. van Loon et al. (1999) + new MSX sample

  22. Superwind mass-loss rates Conversion of radiative momentum:

  23. Superwind mass-loss rates Conversion of radiative momentum: Multiplescattering: Gail & Sedlmayr (1986)

  24. Superwind mass-loss rates Multiple scattering limit predicts:

  25. Superwind mass-loss rates Multiple scattering limit predicts:

  26. LMC versus galactic bulge Alard et al. (2001)

  27. Temperature and evolution Galactic bulge observations: Alard et al. (2001)

  28. Temperature and evolution Galactic bulge observations: Alard et al. (2001) Hydrodynamic models (carbon stars): Arndt, Fleischer & Sedlmayr (1997) Wachter et al. (2002)

  29. Superwind stars in the LMC Cluster superwind carbon star LI-LMC 1813: luminosity, metallicity (20-25% solar), mass Van Loon et al. (2003)

  30. 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)

  31. Superwind stars in the LMC Van Loon et al. (2005)