Abstract
Optical spectroscopy of the blue star KIC 10449976 shows that it is an extremely heliumrich subdwarf with effective temperature Teff = 40 000 ± 300K and surface gravity log g = 5.3 ± 0.1. Radial-velocity measurements over a 5 d time-scale show an upper variability limit of ≈50 ± 20 km s-1. Kepler photometry of KIC 10449976 in both long and short cadence modes shows evidence for a periodic modulation on a time-scale of ≈3.9 d. We have examined the possibility that this modulation is not astrophysical but conclude that it is most likely real. We discuss whether the modulation could be caused by a low-mass companion, by stellar pulsations or by spots. The identification of any one of these as cause has important consequences for understanding the origin of helium-rich subdwarfs.
Original language | English |
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Pages (from-to) | 3207-3213 |
Number of pages | 7 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 429 |
Issue number | 4 |
DOIs | |
Publication status | Published - Mar 11 2013 |
Externally published | Yes |
Keywords
- Stars: abundances
- Stars: chemically peculiar
- Stars: individual:KIC 10449976
- Subdwarfs
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science