3 Search for planetary nebulae around hot post-AGB stars

  A search for PN around hot (pre-) white dwarfs by means of wide-field narrow-band H$\alpha$ CCD imaging was performed at the northern sky (1.23 m telescope at Calar Alto, exposure times of one hour) by Werner et al. (1997). 16 objects were observed which revealed only one candidate for a PN - an asymmetric nebulosity was found around PG0109+111.

Our search had the same aim: To find "missing'' PN (Sect.1) which have not been detected so far, maybe because of their too-low surface brightness. However, no H$\alpha$ emission which could stem from a nebula is detected on these images.

  

Table 2: Targetlist for our PN search. $T_\mathrm{eff}$ and $\log g$ are taken from Dreizler & Heber (1998); Dreizler & Werner (1996, 1997); Werner et al. (1996, 1997)