The dwarf nova Z Chamaeleontis

Spectroscopic observations of Z Cha in quiescence are presented. The data include moderate spectral resolution scans over most of an orbit and with high time resolution through eclipse. Various lower resolution spectra and UV and optical spectrophotometry are also discussed. The spectrum is dominated by broad double peaked Balmer emission lines; He I emission and absorption lines are visible and there is no Balmer discontinuity. The Balmer line wings extend to +- 2100 km s-1; this implies a minimum mass Msub(WD) > 0.4 solar mass if the compact object is a helium white dwarf. The depth of the central dip in the double peaked profiles and the peak-to-peak velocity separation increase from Hα through to Hdelta suggesting absorption effects. The values of the peak-to-peak velocity separation range from 1100 km s-1 (Hα) to 1650 km s-1 (Hdelta). The line emissivity as a function of disc radius is discussed and power-law fits given. (author)