ON THE MASS OF THE WHITE-DWARF IN UZ FORNACIS

We present phase-resolved spectroscopy of the eclipsing AM Herculis st ar UZ For obtained when the system was in its low state of accretion. Faint residual Her-emission and NaI absorption were used to trace the secondary star and infer its orbital velocity K-2. The measured radial velocity amplitude of NaI K-2sin i = 285+/-50 km s(-1) suggests a lo w-mass white dwarf with M-wd = 0.44+/-0.15 M.(1 sigma-errors). The H a lpha emission line on the other hand, visible only for part of the orb ital cycle and supposed to originate only on the illuminated hemispher e facing the white dwarf, displays a similar radial velocity amplitude , K-2' sin i = 308 +/- 27 km s(-1). The standard K-2-correction applie d by us then suggests a white dwarf mass of up to 1 M.. Compared with earlier results the new ones enlarge the window in which the white dwa rf mass may lie and resolves the conflict between mass estimates based on photometry and spectroscopy. They leave some ambiguity in the loca tion of emission and absorption components in these and former observa tions.