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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 261.9 s and uniform splitting at a frequency ~2.68 h^{-1}. One year later the system had fallen in brightness by a further 2.5 mag, showed deep eclipses with a period of 2.6687 h, and the 261.9 s modulation at a reduced amplitude. There is often power near the `subharmonic' at 524 s, 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.