Document Type
Article
Publication Date
3-2021
Abstract
We present modelling of the long-term optical light and radial velocity curves of the binary stellar system CXOGBS J175553.2-281633, first detected in X-rays in the Chandra Galactic Bulge Survey. We analysed 7 yr of optical I-band photometry from Optical Gravitational Lensing Experiment and found long-term variations from year to year. These long-term variations can most likely be explained with by either variations in the luminosity of the accretion disc or a spotted secondary star. The phased light curve has a sinusoidal shape, which we interpret as being due to ellipsoidal modulations. We improve the orbital period to be P = 10.34488 +/- 0.00006 h with a time of inferior conjunction of the secondary star T-0 = HJD2455260.8204 +/- 0.0008. Moreover, we collected 37 spectra over 6 non-consecutive nights. The spectra show evidence for an evolved K7 secondary donor star, from which we obtain a semi-amplitude for the radial velocity curve of K-2 = 161 +/- 6 km s(-1). Using the light-curve synthesis code xrbinary, we derive the most likely orbital inclination for the binary of i = 63.0 +/- 0.7 deg, a primary mass of M-1 = 0.83 +/- 0.06 M-circle dot, consistent with a white dwarf accretor, and a secondary donor mass of M-2 = 0.65 +/- 0.07 M-circle dot, consistent with the spectral classification. Therefore, we identify the source as a long orbital period cataclysmic variable star.
Publication Source (Journal or Book title)
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
First Page
48
Last Page
59
Recommended Citation
Gomez, S., Torres, M. A., Jonker, P. G., Kostrzewa-Rutkowska, Z., van Grunsven, T. F., Udalski, A., Hynes, R. I., Heinke, C. O., Maccarone, T. J., Salinas, R., & Strader, J. (2021). Dynamical modelling of CXOGBS J175553.2-281633: a 10 h long orbital period cataclysmic variable. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 502 (1), 48-59. https://doi.org/10.1093/mnras/stab026
