V795 HERCULIS (=PG 1711+336), A PECULIAR INTERMEDIATE POLAR WITHOUT STRONG X-RAY-EMISSION

The peculiar cataclysmic variable V795 Her (= PG 1711 + 336) has been classified as an intermediate polar because it displays two different and incommensurate periods, a photometric period of 0.d1164865 and a spectroscopic period of 0.1082648. The photometric period has been interpreted as the beat period between the orbital period and the rotation period of the white dwarf. Doubts remain about the intermediate polar model for V795 Her because the predicted rotation period of the white dwarf has not been found in any data and because EXOSAT did not detect any X-ray emission from the system. Also, there is evidence that V795 Her is related to systems with precessing accretion disks. If it is related to such systems, the photometric modulation could be caused by precession of the accretion disk around the white dwarf. We have obtained new photometry of V795 Her. The revised ephemeris for the photometric period is T(min) = JD. 2,446,584.2045(+/- 19) + 0.11648634(+/- 29)E. The photometric period is highly stable; the upper limit to the rate of change of the period is \P\ < 1.7 x 10(-9). We also find quasi-periodic oscillations with periods near 1000 s. There are theoretical and observational grounds for believing that accretion disks cannot have stable precession periods. As the clock that underlies the 2.8 hr photometric modulation is highly stable, we conclude that the modulation is not caused by a precessing disk, that the intermediate polar model remains the most viable model for V795 Her, and that intermediate polars need not be strong X-ray sources.