Analysis of nonradial pulsations of the central star of the planetary nebula K1-16

Journal Article · Sat Jun 01 04:00:00 EDT 1985 · Astrophys. J., Lett. Ed.; (United States)

DOI:https://doi.org/10.1086/184484· OSTI ID:5375337

Starrfield, S; Cox, A N; Kidman, R B; Dean Pesnell, W

We have performed a linear, nonradial, nonadiabatic pulsation stability analysis of stellar models with effective temperatures of 1.50 x 10/sup 5/ K, 1.55 x 10/sup 5/ K, 1.60 x 10/sup 5/ K, and 1.65 x 10/sup 5/ K, and luminosities characteristic of stars evolving from the AGB to the white dwarf cooling sequence. Our purpose is to find unstable pulsation modes with periods as long as those observed in the central star of the planetary nebula, K1-16. These models have masses of 0.6 M/sub sun/ and homogeneous compositions of half-carbon and half-oxygen by mass. All these stellar models exhibit unstable nonradial modes with periods ranging from 1000 to 4000 s. The longest periods were found in the model with T/sub e/ = 1.55 x 10/sup 5/ K, L = 2000 L/sub sun/. The pulsation driving mechanism is the cyclical ionization of carbon and oxygen at temperatures of (2--5) x 10/sup 6/ K. This analysis demonstrates that K1-16 is probably a member of the PG 1159-035 class of sdO variable stars. This star is, therefore, an evolutionary link from the central stars of the OVI planetary nebulae to the hottest non-Da white dwarfs as proposed by Sion, Liebert, and Starrfield. It must also be evolving very rapidly.

• Research Organization: Theoretical Division, los Alamos National Laboratory; and Department of Physics, Arizona State University
• OSTI ID: 5375337
• Journal Information: Astrophys. J., Lett. Ed.; (United States), Journal Name: Astrophys. J., Lett. Ed.; (United States) Vol. 293:1; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON
ELEMENTS
IONIZATION
MATHEMATICAL MODELS
MATHEMATICS
NEBULAE
NONMETALS
NUMERICAL ANALYSIS
OSCILLATION MODES
OXYGEN
PLANETARY NEBULAE
PULSATIONS
STAR EVOLUTION
STAR MODELS
STARS
VARIABLE STARS