1RXS J062518.2+733433: A new intermediate polar

We report the identification of the cataclysmic variable 1RXS J062518.2+733433 as an intermediate polar. The orbital period of the system is determined to be $283.0\pm0.2$ min from the radial velocity variation of ${\mathrm H\alpha}$, measured in an extensive set of time-resolved spectra. Differential optical photometry obtained over a base line of three weeks reveals the presence of coherent variability with a period of $19.788\pm0.002$ min, which we suggest to be the white dwarf spin period. The power spectrum of our photometry also contains a strong signal near the spectroscopically-determined orbital period. The emission lines in 1RXS J062518.2+733433 display a complex multicomponent structure. In the trailed spectrogram of He I λ 6678 we detect a narrow component with a radial velocity semi-amplitude of $\simeq$140 kms, consistent with a possible origin on the irradiated face of the secondary. The absence of eclipses gives an upper limit on the binary inclination of $i\la60^\circ$.