Spectrophotometric properties of the nearest pre-main sequence stars

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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 - PowerPoint PPT Presentation

Transcript of Spectrophotometric properties of the nearest pre-main sequence stars

  • Spectrophotometric properties of the nearest pre-main sequence stars2009. 10. 07

    A-Ran Lyo

  • HR diagramLuminosityTemperaturePre-main sequence

  • Lyo et al. 2004a H 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.

  • Chamaelentis cluster : t = 3 - 5 Myr (Feigelson et al. 2003) ~ 6 Myr (Luhman 2004) 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) Pictoris Moving group : t ~ 2010 Myr (Barrado y Navascues 2001) Lower Centaurus Crux : t = 17 ~ 23 Myr (Mamajek et al. 2002)

    a common kinematic link with the Ophiuchus-Scorpius- Centaurus OB Association

  • Lawson & Feigelson 2000Pre-main sequence evolutionary models

  • Spectral lines

    : Effective temperature (spectral type): Luminosity (surface gravity): Chemical composition (metallicity)

    valuable input for understanding PMS stellar structure and evolution.

  • Chamaeleontis

  • Lyo et al. 2004b Chamaeleontis

  • Comparison of Cha cluster members and dwarfs PC3PC4PC5CaHTiOCaOHLyo et al. 2004b

  • Temperature-sensitive indicesLyo et al. 2004b

  • Gravity-sensitive indicesLyo et al. 2004b

  • Lyo et al. 2008

  • Lawson, Lyo, & Bessell 2009, accepted

  • Lawson, Lyo, & Bessell 2009, accepted

  • Thank you