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Spectrophotometric properties of the nearest pre-main sequence stars

Spectrophotometric properties of the nearest pre-main sequence stars. 2009. 10. 07 A-Ran Lyo. HR diagram. Pre-main sequence. Luminosity. Temperature. H α emission line : accretion disk & chromospheric activity

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Spectrophotometric properties of the nearest pre-main sequence stars

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  1. Spectrophotometric properties of the nearest pre-main sequence stars 2009. 10. 07 A-Ran Lyo

  2. HR diagram Pre-main sequence Luminosity Temperature

  3. Hα emission line : accretion disk & chromospheric activity • Li I absorption line : age indicator because Li I is diminished fast during the very early phase of stellar evolution. Lyo et al. 2004a

  4. ε Chamaelentis cluster : t = 3 - 5 Myr (Feigelson et al. 2003) • ~ 6 Myr (Luhman 2004) • η Cha cluster : t = 5 - 8 Myr (Luhman & Steeghs 2004) • = 7 - 9 Myr (Lyo et al. 2004) • TW Hydrae association : t ~ 8 - 10 Myr (Webb et al. 1999) • β Pictoris Moving group : t ~ 20±10 Myr (Barrado y Navascues 2001) • Lower Centaurus Crux : t = 17 ~ 23 Myr (Mamajek etal. 2002) • a common kinematic link with the Ophiuchus-Scorpius- • Centaurus OB Association

  5. Pre-main sequence evolutionary models Lawson & Feigelson 2000

  6. Spectral lines : Effective temperature (spectral type) : Luminosity (surface gravity) : Chemical composition (metallicity) valuable input for understanding PMS stellar structure and evolution.

  7.  Chamaeleontis

  8. η Chamaeleontis Lyo et al. 2004b

  9. Comparison of η Cha cluster members and dwarfs PC3 PC4 PC5 TiO CaH CaOH Lyo et al. 2004b

  10. Temperature-sensitive indices Lyo et al. 2004b

  11. Gravity-sensitive indices Lyo et al. 2004b

  12. Lyo et al. 2008

  13. Lawson, Lyo, & Bessell 2009, accepted

  14. Lawson, Lyo, & Bessell 2009, accepted

  15. Thank you

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