[vsnet-alert 9516] V713 Cep eclipses and period measurement

[Denis Denisenko]

During the 3.5-hr photometric run with the 1.5-m Russian-Turkish 
Telescope (RTT150) on August 25th, 2007 the eclipses in the cataclysmic 
variable V713 Cep were discovered.  The light curve showing two eclipses 
is available at http://hea.iki.rssi.ru/~denis/V713Cep-RTT_LC070825.gif 
(28 kB). Using the preliminary ephemeris from the first night, the 
additional 45-min photometry was made on August 26th.  The preliminary 
value of period is 0.08542(2)d, the range of variability in V band is 
about 18.0-21.0:.  At the minimum star was beyond the limit of 60-sec 
exposure, so the real depth of eclipse can be more than 3 magnitudes.  
The follow-up observations are planned with RTT150 later when the Moon 
is gone to measure the minimum magnitude and to improve the period.  The 
eclipse ephemeris is as follows:
T = 2454338.371 + 0.08542 * E.

This variable was originally discovered by S.Antipin as dwarf nova on 
the Moscow archive plates (see Antipin and Croll, 2003, IBVS 5461).  
Only two outbursts were found (1984 Aug. 30 on Sonneberg plate and 1989 
Oct. 30 - Nov. 5 on Moscow plates) with the star reaching 15.3 and 15.5 
magnitude.

V713 Cep is very similar to UGSU-type star DV UMa (orbital period 
0.085853d) which shows both the eclipses from 18.3 to 20.5 mag, 
outbursts to 14.0-15.4 mag every 770 days and superhumps with 0.0887d 
period.

Long-term monitoring of V713 Cep in search for the future outbursts is 
encouraged.  Coordinates of the star are:
R.A. = 20 46 38.66, Decl. = +60 38 03.6 (2000.0)
The color-combined (BRIR) 10'x9' DSS finder chart is available at:
http://hea.iki.rssi.ru/~denis/V713Cep-comps.gif (176 kB). USNO-A2.0 B 
and R magnitudes of several stars are shown. In plotting the light curve 
above the pseudo-V (0.5*R+0.5*B) magnitudes of two comparison stars 
(R=16.3, B=17.5 and R=16.8, B=17.8) were used.

Denis V. Denisenko
Space Research Institute (IKI)
Russian Academy of Sciences
Currently at the Turkish National Observatory (TUG)
5648282 (at) mail (dot) ru