Carbon-enhanced stars with short orbital and spin periods

Whitehouse, L. J.; Farihi, J.; Howarth, I. D.; Mancino, S.; Walters, N.; Swan, A.; Wilson, T. G. und Guo, J. (2021): Carbon-enhanced stars with short orbital and spin periods. In: Monthly Notices of the Royal Astronomical Society, Bd. 506, Nr. 4: S. 4877-4892

Abstract

Many characteristics of dwarf carbon stars are broadly consistent with a binary origin, including mass transfer from an evolved companion. While the population overall appears to have old-disc or halo kinematics, roughly 2 percent of these stars exhibit H alpha emission, which in low-mass main-sequence stars is generally associated with rotation and relative youth. Its presence in an older population therefore suggests either irradiation or spin-up. This study presents time-series analyses of photometric and radial-velocity data for seven dwarf carbon stars with H alpha emission. All are shown to have photometric periods in the range 0.2-5.2d, and orbital periods of similar length, consistent with tidal synchronization. It is hypothesized that dwarf carbon stars with emission lines are the result of close-binary evolution, indicating that low-mass, metal-weak, or metal-poor stars can accrete substantial material prior to entering a common-envelope phase.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 0035-8711
• Sprache: Englisch