A new class of variables, the ZZ Leporis stars, is proposed. These are variable central stars of young Planetary Nebulae exhibiting roughly sinusoidal (semi)regular photometric and/or radial velocity variations with time scales of several hours. Fourteen of these objects have been identified and they share two more important characteristics: their temperatures are less than 50000 K and all show hydrogen-rich spectra. The most likely reason for the variability is stellar pulsation. Another possibility would be variable stellar mass loss, but in that case the mechanism causing it must be different from that operating in massive O stars.
Interplay of Periodic, Cyclic and Stochastic Variability in Selected Areas of the H-R Diagram
- Pub Date:
- March 2003