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Single and Composite Hot Subdwarf Stars in the Light of 2MASS All-Sky Photometry

M. A. Stark·Richard A. Wade·G. B. Berriman
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Abstract

Utilizing the Two Micron All Sky Survey (2MASS) All-Sky Data Release Catalog, we have retrieved useful near-IR J, H, and Ks magnitudes for more than 800 hot subdwarfs (sdO and sdB stars) drawn from the "Catalogue of Spectroscopically Identified Hot Subdwarfs" (Kilkenny, Heber, & Drilling 1988, 1992). This sample size greatly exceeds previous studies of hot subdwarfs. We find that, of the hot subdwarfs in Kilkenny et al., ~40% in a magnitude limited sample have colors that are consistent with the presence of an unresolved late type (FGK) companion. Binary stars are over-represented in a magnitude limited sample. In an approximately volume limited sample the fraction of composite-color binaries is ~25%.

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M. A. Stark, Richard A. Wade, G. B. Berriman. 2003-09-05. Single and Composite Hot Subdwarf Stars in the Light of 2MASS All-Sky Photometry. https://doi.org/10.1023/b%3Aastr.0000044340.84919.2b

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