2017/03/08 by A. Bruch, Albert Bruch, Berto Monard · 1 citation
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Binary number #Brightness #Cataclysmic variable star #Dwarf nova #Eclipse #Ephemeris #Gamma-ray bursts and supernovae #Intermediate polar #Light curve #Orbital inclination #Orbital period #Photometry (optics) #Physics #RADIUS #Satellite #Stars #White dwarf #astro-ph.SR
paper · pdf · doi:10.1016/j.newast.2017.03.001
openalex publication_date 2017/03/08 · arxiv created 2017/03/14 · arxiv updated 2017/03/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Although comparatively bright, the cataclysmic variable GY Hya has not attracted much attention in the past. As part of a project to better characterize such systems photometrically, we observed light curves in white light, each spanning several hours, at Bronberg Observatory, South Africa, in 2004 and 2005, and at the Observatório do Pico dos Dias, Brazil, in 2014 and 2016. These data permit to study orbital modulations and their variations from season to season. The orbital period, already known from spectroscopic observations of Peters & Thorstensen (2005), is confirmed through strong ellipsoidal variations of the mass donor star in the system and the presence of eclipses of both components. A refined period of 0.34723972~(6) days and revised ephemeris are derived. Seasonal changes in the average orbital light curve can qualitatively be explained by variations of the contribution of a hot spot to the system light together with changes of the disk radius. The amplitude of the ellipsoidal variations and the eclipse contact phases permit to put some constraints on the mass ratio, orbital inclination and the relative brightness of the primary and secondary components. There are some indications that the disk radius during quiescence, expressed in units of the component separation, is smaller than in other dwarf novae.