A search for planetary nebulae around hot white dwarfs *
K. Werner 1,
K. Bagschik 2,
T. Rauch 1 and
R. Napiwotzki 3
Received 2 June 1997 / Accepted 10 July 1997
We have performed a search for old planetary nebulae around hot white dwarfs by direct H narrow-band imaging. The 16 examined objects are white dwarfs representing different spectral subtypes, comprising DA and various non-DA stars, among them being PG 1159 stars and white dwarfs exhibiting spectral signatures of ongoing mass-loss by ultra-hot winds.
The search was entirely negative - with one possible exception: PG 0109+111, which is the most massive DO white dwarf known (M=0.74 ) and among the hottest DOs ( =110 000 K). An asymmetric nebulosity extends about from the star to the south-west, and there are hints that it extends even further out. If our detection is in fact the first definite case of a PN around a DO white dwarf it needs to be investigated by detailed spectroscopic observations.
Key words: stars: evolution stars: AGB and post-AGB white dwarfs planetary nebulae: general
* Based on observations obtained at the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institut für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy
Send offprint requests to: K. Werner
© European Southern Observatory (ESO) 1997
Online publication: April 6, 1998