Photometric variability in four hot subdwarf stars

Photometric variability in four hot subdwarf stars

We present new photometry for four sdB stars. EC 00404−4429 is a known spectroscopic binary, probably with a white dwarf companion, for which we find evidence of a small ellipsoidal effect and small-amplitude slow (g-mode) pulsation. EC 09174−1033 shows variability on a time-scale of around 2 h and...

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Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2016-03, Vol.457 (1), p.723-729
Main Authors: Kilkenny, D, Koen, C
Format: Article
Language:eng
Subjects:
Astronomy
Binary stars
Frequencies
Oscillations
Photometry
Pulsars
Pulsation
Reflection
Spectroscopy
Star & galaxy formation
Stars
White dwarf stars
White dwarfs
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Summary:We present new photometry for four sdB stars. EC 00404−4429 is a known spectroscopic binary, probably with a white dwarf companion, for which we find evidence of a small ellipsoidal effect and small-amplitude slow (g-mode) pulsation. EC 09174−1033 shows variability on a time-scale of around 2 h and is probably also a slowly pulsating sdB star, although the light variations could be a result of binary orbital effects. EC 15094−1725 is a rapidly pulsating sdB star with a dominant, large amplitude (∼0.03 mag) mode near 7120 μHz (period ∼140.5 s) and much weaker oscillations (∼0.004 mag) near 6876 and 7761 μHz. PHL 457 is a known spectroscopic binary for which we find two weak frequencies around 200–300 μHz (periods ∼ 1 h) – indicative of a slowly pulsating sdB star. A third (weaker) frequency at the orbital period of 0.31 d is likely to be caused by a reflection effect.
ISSN:0035-8711
1365-2966