1996A&A...309..820D

The discovery of a new peculiar PG1159 star by follow-up spectroscopy of candidates selected from objective-prism plates of the Hamburg Schmidt Survey is presented. From a NLTE model atmosphere analysis an effective temperature of 130000±10000K and a surface gravity of logg=6.2±0.2 are determined, which together with the high carbon abundance place HS2324+3944 in the region of low gravity PG1159 stars. The detection of hydrogen, however, makes HS2324+3944 unique amongst the PG1159 stars. While three central stars of Planetary Nebulae have spectra similar to HS2324+3944, hydrogen could not be detected up to now in any PG1159 star not associated with a nebula. The abundances of helium, carbon and nitrogen (C/He=0.3, N/He<2x10^–3) are similar to that of "normal" PG1159 stars while the O abundance is found to be somewhat lower than "normal" (O/He=2-10x10^–3).