Long-term photometry of the eclipsing dwarf nova V893 Scorpii

Abstract

Context. The cataclysmic variable V893 Sco is an eclipsing dwarf nova which, apart from outbursts with comparatively low amplitudes, exhibits a particularly strong variability during quiescence on timescales of days to seconds. Aims. The present study aims to update the outdated orbital ephemerides published previously, to investigate deviations from linear ephemerides, and to characterize non-random brightness variations in a range of timescales. Methods. Light curves of V893 Sco were observed on 40 nights, spanning a total time base of about 14 years. They contain 114 eclipses which were used to significantly improve the precision of the orbital period and to study long-term variations of the time of revolution. Oscillations and similar brightness variations were studied with Fourier techniques in the individual light curves. Results. The orbital period exhibits long-term variations with a cycle time of 10.2 years. They can be interpreted as a light travel time effect caused by the presence of a giant planet with approximately 9.5 Jupiter masses in a 4.5 AU orbit around V893 Sco. On some nights transient semi-periodic variations on timescales of several minutes can be seen which may be identified as quasi-periodic oscillations. However, it is difficult to distinguish whether they are caused by real physical mechanisms or if they are the effect of an accidental superposition of unrelated flickering flares. Simulations to investigate this question are presented.

Cyclic Period Oscillation of the Eclipsing Dwarf Nova DV UMa

“…Also note that the brown dwarf companion in V471 Tau was excluded by Hardy et al (2015) but a new study agrees with the presence of a brown dwarf companion (Vaccaro et al 2015). Moreover, some possible planets orbiting the eclipsing CVs or pre-CVs were also presented such as V893 Sco (Bruch 2014), V2051 Oph , OY Car , DP Leo Beuermann et al 2011), HU Aqr (Qian et al 2011;Goździewski et al 2015), UZ For Potter et al 2011) and NN Ser (Marsh et al 2014). These discoveries suggest that the PCEBs may be one of the most common host stars.…”

“…The LTT shows a periodic variation in O − C diagram. The timing method has recently been used to detect possible extrasolar planets around CVs such as V2051 Oph , Z Cha (Dai et al 2009), OY Car and V893 Sco (Bruch 2014).…”

A possible giant planet orbiting the cataclysmic variable LX Ser

“…Now we consider whether the existence of a planet with the characteristics derived in the previous subsection is compatible with the evolution of LX Ser from a wide orbit binary to a CV. Similar consideration has been carried out in recent work of Bruch (2014). If the planet can survive the common envelope phase of the binary, the separation of the planet from the binary should be larger than the radius R CE of the common envelope.…”

Discovery of deep eclipses in the cataclysmic variable IPHAS J013031.89+622132.3

“…Therefore, ephemeris 2 is suitable for future investigations of long-term changes of the orbital period using O -C. Such changes might be caused by variations of the rotational oblateness of the latetype companion during its activity cycle (e.g., Rubenstein et al 1991;Applegate 1992). Such changes might also be caused by a possible giant planet orbiting around the centre of gravity in J0130 (e.g., Bruch 2014;Beuermann et al 2011).…”