The Temperature Structure of Be Star Disks in the Small Magellanic Cloud

Abstract

The temperature structure of Be star circumstellar disks at the sub-solar metallicity appropriate to the Small Magellanic Cloud (SMC) is investigated. It is found that for central stars of the same spectral type, Be star disks in the SMC are systematically hotter by several thousand degrees compared to Milky Way (MW) disks with the same density structure. For early spectral types (B0e - B3e), this results in systematically smaller Hα equivalent widths for Be stars in the SMC. The implication of this result on Be star frequency comparisons between MW and SMC clusters is shown to be a 5 - 10% lowering of the detection efficiency of Be stars in SMC clusters. These calculations are also compared to the known Hα equivalent width distributions in the MW and SMC. For the MW, reasonable agreement is found; however, for the SMC, the match is not as good and systematically larger Be star disks may be required.

31 pages, 10 figures, Accepted for publication in the astrophysical Journal

References in corpus (15)

• A Grid of NLTE Line-Blanketed Model Atmospheres of Early B-type Stars
• The empirical metallicity dependence of the mass-loss rate of O- and early B-type stars
• Effects of gravitational darkening on the determination of fundamental parameters in fast rotating B-type stars
• The VLT-FLAMES survey of massive stars: constraints on stellar evolution from the chemical compositions of rapidly rotating Galactic and Magellanic Cloud B-type stars
• The VLT-FLAMES survey of massive stars: Evolution of surface N abundances and effective temperature scales in the Galaxy and Magellanic Clouds
• The VLT-FLAMES survey of massive stars: atmospheric parameters and rotational velocity distributions for B-type stars in the Magellanic Clouds
• The Thermal Structure of the Circumstellar Disk Surrounding the Classical Be Star gamma Cassiopeia
• Mass and angular momentum loss via decretion disks
• Be phenomenon in open clusters: Results from a survey of emission-line stars in young open clusters
• Constraining the Physical Parameters of the Circumstellar Disk of chi Ophiuchi
• A Pulsational Mechanism for Producing Keplerian Disks around Be Stars
• Be Star Disk Models in Consistent Vertical Hydrostatic Equilibrium
• A Parameter Study of Classical Be Star Disk Models Constrained by Optical Interferometry
• The Thermal Structure of Gravitationally-Darkened Classical Be Star Disks
• Sub-milliarcsecond precision spectro-astrometry of Be stars

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• The Correlation Between Hα Emission and Visual Magnitude During Long-Term Variations in Classical Be Stars
• Rotational Mixing in Be Stars: Nitrogen Abundances for a Sample of Be Stars from the MiMeS Survey
• Quiescent and active phases in Be stars: A WISE snapshot of young galactic open clusters
• On the Intrinsic Continuum Linear Polarization of Classical Be Stars: The Effects of Metallicity and One-Armed Density Perturbations