GSC 4560–02157: a new long-period eclipsing cataclysmic variable star

Abstract

We study the newly discovered variable star GSC 4560-02157. CCD photometry was performed in 2013-2014, and a spectrum was obtained with the 6-m telescope in June, 2014. GSC 4560-02157 is demonstrated to be a short-period (P = 0.265359 d ) eclipsing variable star. All its flat-bottom primary minima are approximately at the same brightness level, while the star's out-of-eclipse brightness and brightness at secondary minimum varies considerably (by up to 0.6 m ) from cycle to cycle. Besides, there are short-term (time scale of 0.03-0.04 days) small-amplitude brightness variations out of eclipse. This behavior suggests cataclysmic nature of the star, confirmed with a spectrum taken on June 5, 2014. The spectrum shows numerous emissions of the hydrogen Balmer series, HeI, HeII.

Physical parameters and orbital period variation of a newly discovered cataclysmic variable GSC 4560–02157

“…Aperture photometry was performed with the MAXIM DL package. All mideclipse times (including the data published by Khruslov et al (2015)) were determined by using a parabolic fitting method because the light variations around those minima are nearly-symmetrical. All available CCD mid-eclipse times of GSC 4560-02157 are listed in Table 1.…”

“…Since its discovery, the changes in the orbital period have never been analyzed. By adopting photometric data from Khruslov et al (2015), a total of 16 minima were obtained. Moreover, we also observed this target on 2016 April 22 and 28 and two mid-eclipse times were measured.…”

“…GSC 4560-02157 is a newly discovered eclipsing CV (Khruslov et al 2015). This CV was found to be a variable star from the Northern Sky Variability Survey Database (Wozniak et al 2004) and attracted a researcher (Khruslov) attention in 2005.…”

“…This CV was found to be a variable star from the Northern Sky Variability Survey Database (Woźniak et al 2004) and attracted the attention of a researcher (Khruslov) in 2005. Khruslov et al (2015) reported spectroscopic and many photometric observations, and the results show that GSC 4560-02157 is an eclipsing binary with a long orbital period of about 6.37 h. By using photometric observations, they found that the out-ofeclipse brightness demonstrates sensible changes but the primary eclipse was relatively stable. Moreover, its eclipse profile and spectral features are very similar to another long period eclipsing CV, GY Cnc.…”

“…Lastly, these authors confirmed that GSC 4560-02157 is an eclipsing CV. In the present paper, by using the data published by Khruslov et al (2015), we obtained some basic system parameters and mid-eclipse times. Combining these mid-eclipse times with our latest data, the linear ephemeris was revised and a cyclic variable in the O − C diagram was found.…”