A Spectroscopic Orbit for Regulus

Abstract

We present a radial velocity study of the rapidly rotating B-star Regulus that indicates the star is a single-lined spectroscopic binary. The orbital period (40.11 d) and probable semimajor axis (0.35 AU) are large enough that the system is not interacting at present. However, the mass function suggests that the secondary has a low mass (M_2 > 0.30 M_sun), and we argue that the companion may be a white dwarf. Such a star would be the remnant of a former mass donor that was the source of the large spin angular momentum of Regulus itself.

18 pages, 2 figures, ApJL in press

References in corpus (5)

• A Grid of NLTE Line-Blanketed Model Atmospheres of Early B-type Stars
• Evolution towards the critical limit and the origin of Be stars
• Cross-Correlation and Maximum Likelihood Analysis: A New Approach to Combine Cross-Correlation Functions
• The Discovery of a Companion to the Lowest Mass White Dwarf
• Rotation and massive close binary evolution

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