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.
Item Type: | Journal article |
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Faculties: | Physics |
Subjects: | 500 Science > 530 Physics |
ISSN: | 0035-8711 |
Language: | English |
Item ID: | 103045 |
Date Deposited: | 05. Jun 2023, 15:41 |
Last Modified: | 05. Jun 2023, 15:41 |