A1 Refereed original research article in a scientific journal
Red giant pulsations from the suspected symbiotic star StHA 169 detected in Kepler data
Authors: Gavin Ramsay, Pasi Hakala, Steve B. Howell
Publisher: Oxford Journals
Publishing place: Oxford
Publication year: 2014
Journal: Monthly Notices of the Royal Astronomical Society
Journal acronym: MNRAS
Volume: 442
Issue: 1
First page : 489
Last page: 494
Number of pages: 6
ISSN: 0035-8711
DOI: https://doi.org/10.1093/mnras/stu800
We present Kepler and Swift observations of StHa 169 which is currently classified as a symbiotic binary. The Kepler light curve shows quasi-periodic behaviour with a mean period of 34 d and an amplitude of a few per cent. Using Swift data, we find a relatively strong UV source at the position of StHa 169 but no X-ray counterpart. Using a simple two-component blackbody fit to model the combined Swift and 2MASS spectral energy distribution and an assessment of the previously published optical spectrum, we find that the source has a hot (˜10 000 K) component and a cooler (˜3700 K) component. The Kepler light is dominated by the cool component and we attribute the variability to pulsations in a red giant star. If we remove this approximate month long modulation from the light curve, we find no evidence for additional variability in the light curve. The hotter source is assigned to a late B or early A main-sequence star. We briefly discuss the implications of these findings and conclude that StHA 169 is a red giant plus main-sequence binary.
Downloadable publication This is an electronic reprint of the original article. |