Time-resolved observations of the short period CV SDSS J123813.73-033933
  We present simultaneous spectral and photometric observations of SDSS J123813.73-033933.0. From Ha radial velocity measurements we determined the orbital period of the system to be 0.05592+/-0.00002 days (80.53 min). The spectrum shows double Balmer emission lines flanked by strong, broad absorption, indicating a dominant contribution from the white dwarf. The photometric light curve shows complex variability. The system undergoes cyclic brightening up to 0.4 mag which are semi-periodical on short time scales with periods of the order of 7-12 hours. We also detect 40.25 min variability (~0.15 mag) in the light curve, that corresponds to half the orbital period. Its amplitude increases with the cyclic brightening of the system. 
S.V. Zharikov (1), G. H. Tovmassian (1), V. Neustroev (2), R. Michel   (1), R. Napiwotzki (3) ((1) OAN IA UNAM, Mexico, (2) ...