Close Binary (and Pulsating) Nuclei of Planetary Nebulae
Abstract
Photometric observations of the nuclei of planetary nebulae are discussed in relation to the possible role of the planetary nebulae as the ancestors of the cataclysmic binaries. Extensive observations in the B region of seven central stars of planetary nebulae have detected no variability in excess of 0.01 magnitudes in six of the stars, thus demonstrating that some planetary nebulae are certainly not close binaries. The central star of Kl-2, however, has been discovered to be a pulsating variable, varying from 16.4 to 17.8 magnitude in the blue with a period of 0.6707 days. The light curve was found to be a one-cycle sinusoidal, almost certainly due to pulsation rather than orbital motion in a binary system, although the pulsation mechanism for such variables remains obscure.
- Publication:
-
IAU Colloq. 53: White Dwarfs and Variable Degenerate Stars
- Pub Date:
- 1979
- Bibcode:
- 1979wdvd.coll..266B
- Keywords:
-
- Binary Stars;
- Planetary Nebulae;
- Stellar Evolution;
- Stellar Oscillations;
- Astronomical Photometry;
- Stellar Magnitude;
- Variable Stars;
- Astrophysics