The eclipsing intermediate polar V597 Pup (Nova Puppis 2007)

Photometric observations of V597 Pup made in 2008, 9.1 mag below maximum, 4 months after eruption, showed no certain orbital modulation but exhibited a quintuplet of oscillations centred on a period 261.9s and uniform splitting at a frequency ~2.68h^-1. One year later, the system had fallen in brightness by a further 2.5mag, showed deep eclipses with a period of 2.6687h, and the 261.9s modulation at a reduced amplitude. There is often power near the `subharmonic' at 524s showing that the shorter periods observed are actually first harmonics.

V597 Pup is thus an intermediate polar, and is in the `orbital period gap'. Furthermore, it is the first to show a prominent secondary eclipse, caused by passage of the optically thick disc in front of the irradiated side of the secondary star.