THE WINDS OF WC10 CENTRAL STARS OF PLANETARY-NEBULAE

We present the results of an analysis of the winds of two WC10 central stars of planetary nebulae, CPD-56 degrees 8032 and He 2-113. These t wo stars have remarkably similar spectra, although the former exhibits somewhat broader emission line widths. High resolution spectra (up to R = 50 000) were obtained in May 1993 for both objects at the 3.9 m A AT, using the UCL Echelle Spectrograph. The fluxes in individual C II auto-ionising multiplet components, many of which were blended, were d erived. Lines originating from auto-ionising resonance states situated in the C2+ continuum are very sensitive to the electron temperature, since the population of the these levels is close to LTE. The measured widths and profile shapes of these transitions are presented and are in excellent agreement with those predicted on the basis of their calc ulated auto-ionising lifetimes. The wind electron temperature is deriv ed for both stars from the ratio of the fluxes in four such transition s (T-e=18 500 K +/- 1 500 K for CPD-56 degrees 8032 and T-e=13 600 K /- 800 K for He 2-113). Optical depth effects are investigated using n ormal recombination lines to obtain an independent wind electron tempe rature estimate in excellent agreement with the dielectronic line anal ysis.