A search for pulsations in planetary nebulae nuclei
The author presents the results of a survey of the central stars of planetary nebulae design to detect g-mode pulsations driven by hydrogen and/or helium shell burning. Using newly developed high-speed photometric instrumentation to overcome the inherent difficulties in observing these central stars in the presence of their nebulae, he has obtained time-series photometric data for 51 central stars in an effort to detect the g-mode pulsations predicted by Kawaler and his colleagues. He detects no periodic variations, for periods between 40 and 500 seconds, in the data down to a limit of approximately 0.5 (average) millimagnitudes. Since the theoretical calculations require these pulsations in the presence of shell burning, he must conclude that either the shell burning sources are extinguished prior to this evolutionary stage, or some mechanism is inhibiting the growth of these pulsations. If the shell burning source is indeed extinguished prior to the central star becoming a white dwarf, then this implies that white dwarfs are formed with hydrogen layer masses less than 10{sup {minus}6}M mass of sum.
- Research Organization:
- Texas Univ., Austin, TX (USA)
- OSTI ID:
- 5253604
- Country of Publication:
- United States
- Language:
- English
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Hydrogen shell game - pulsational instabilities in hydrogen shell-burning planetary nebula nuclei
SHORT-PERIOD g-MODE PULSATIONS IN LOW-MASS WHITE DWARFS TRIGGERED BY H-SHELL BURNING
Related Subjects
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DWARF STARS
HELIUM BURNING
HYDROGEN BURNING
MASS
NEBULAE
PHOTOMETRY
PLANETARY NEBULAE
PULSATIONS
STAR BURNING
STAR EVOLUTION
STARS
VARIATIONS
WHITE DWARF STARS