Detection of eclipses in the suspected V Sge star IPHAS J025827.88+635234.9

We report results of photometry of the suspected V Sge star IPHAS J025827.88+635234.9. The observations were obtained over 25 nights in 2011 and 2012. The total duration of the observations was 153 h. We discovered eclipses typical of cataclysmic variables and flickering, which is also a hallmark of cataclysmic variables. These discoveries characterise this star as a normal cataclysmic variable but not as a star of the V Sge type, as was previously supposed. The eclipse period is equal to 5.882274±0.000008 h. Its depth is equal to 0.3 mag. The full eclipse width is quite large and equal to $(0.160\pm0.011)P_{\rm orb}$ . We obtained an eclipse ephemerid with a formal shelf life of about 500 yr (a 1σ confidence level). This ephemerid is good for investigations of long-term period changes. The eclipse has a complicated two-component V-shaped profile. This profile suggests that the accretion disc is very structured and can consist of an extended disc halo and a quite distinct central part. The off-eclipse light curve is also complicated. It shows two orbital humps at the orbital phases 0.4 and 0.9 and a deep depression at the orbital phase 0.14. By using the period-luminosity-colours relation found by Ak et al., we estimate the distance of this star in the range 660–730 pc. The corresponding absolute visual magnitude is roughly by 1 mag brighter than that for an average cataclysmic variable with the same orbital period. The noted unusual properties of the eclipse profile and off-eclipse light curve can be related with this enlarged luminosity.