Multifilter time-series observations of eleven blue short-period atlas variable stars
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Date
2023
Journal Title
Journal ISSN
Volume Title
Publisher
IOP Publishing
Abstract
Eleven periodic variable stars were observed photometrically through two to four filters from the set UBVRCIC.
Phase-folded data for each star cover full cycles of variation. Spectral energy distributions, based on absolute
photometry extracted from the literature, are used to inform models of the stars. The stars include four eclipsing
systems with hot subdwarfs of spectral type O or B (sdO/B). Periods are in the range 1.8–2.2 hr. Four reflectioneffect binaries, with amplitudes as large as 0.5 mag in the RC filter were observed; periods range from 1.6 to 2.4 hr.
In two of these latter systems, the primary stars are also sdB stars, while two have white-dwarf components. In all
eight of these binaries the companion stars are probably M dwarfs. The remaining three stars are pulsators: one
large-amplitude δ Scuti star previously misclassified as an eclipsing system; one field SX Phe star near the Galactic
plane; and one multiperiodic high-luminosity star of unknown type. The amplitude is usually a strong function of
the wavelength in pulsating stars, but this is not the case for the high-luminosity variable. One possible explanation
is that the luminous star has a pulsating companion. The SX Phe and high-luminosity star are both heavily
reddened (AV > 5 mag).
Description
Keywords
Astronomy, Physics, Subdwarf stars, Cosmology
Citation
Koen, C. et al. (2023). Multifilter time-series observations of eleven blue short-period atlas variable stars. Astronomical Journal, 165(4), 142. 10.3847/1538-3881/acb92f