ORBITAL STUDIES OF THE CATACLYSMIC VARIABLES CZ-ORIONIS, V1193-ORIONIS AND BZ-URSAE-MAJORIS

Time-resolved spectroscopy reveals the orbital periods of three catacl ysmic variables. CZ Ori has an orbital period of 0.2189 d. This is wit hin 3 per cent of a prediction relating orbital period and dwarf nova outburst decline time. We find the M2.5 +/- 1.0 secondary, and infer a n absolute magnitude for CZ Ori in R(KC) of 8.5 +/- 1.0 and a distance of 260 +/- 110 pc. V1193 Ori, also called Hamuy's Blue Variable, has an orbital period of 0.165 d. In 1988, H alpha emission line profile v ariations suggested red star illumination. In 1989, this line's red wi ng flared at orbital phases 0.2 and 0.8. We set limits for the absolut e magnitude in R(KC) of < 5.9 and for the distance of > 470 pc. BZ UMa has an orbital period of 0.0679 d, shown by H alpha radial velocities and an S-wave. The velocities have anomalous low-frequency variations , strongest in the line wings. This rumbling, observed during all thre e observing runs, is of amplitude comparable to the orbit's. Explanati ons of instrumental effects, magnetism or disc waves are considered. T he M5.5 +/- 0.5 secondary implies an absolute magnitude for BZ UMa in R(KC) of 10.7 (+ 0.7/- 0.9) and a distance of 110 (+ 44/ -51)pc.