A compact planetary nebula around the hot white dwarf EGB 6/PG 0950 + 139

Journal Article · Wed Nov 01 04:00:00 EST 1989 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168006· OSTI ID:7164022

Liebert, J; Green, R; Bond, H E; Holberg, J B; Wesemael, F ^[1]

---

1. Steward Observatory, Tucson, AZ (USA) Mount Wilson and Las Campanas Observatories, Pasadena, CA (USA) Kitt Peak National Observatory, Tucson, AZ (USA) Space Telescope Science Institute, Baltimore, MD (USA) Arizona Univ., Tucson (USA) Montreal Universite, Montreal (Canada)

The remarkable central star (0950 + 139), a very hot DA/DAO white dwarf, of the planetary nebula EGB 6 is described. Follow-up observations relevant to the analyses of both the nebula and the stellar photosphere are presented. Three kinds of scenarios are discussed to account for the existence of this peculiar nebula, but none appears very promising. The first consideration is that the nebula was ejected from the white dwarf as a discret event. This hypothesis is heavily constrained by the nebular size, density, and expansion rate; by the low luminosity and radius of the star; and by the absence of evidence for variation in density-sensitive forbidden lines from 1978 to 1987. No plausible mechanism can cause the observed amount of mass to be lost directly from a white dwarf in a steady or sporadic wind, at outflow velocities orders of magnitude below the escape velocity. Final consideration is given to the possibility that the gas is lost from a close companion star, but there is no evidence that this is a close binary system. 45 refs.

• OSTI ID: 7164022
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 346; ISSN ASJOA; ISSN 0004-637X
• 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
ABSORPTION SPECTRA
ABUNDANCE
BINARY STARS
BRIGHTNESS
DWARF STARS
EMISSION SPECTRA
EXPANSION
INTERSTELLAR SPACE
MASS TRANSFER
NEBULAE
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLANETARY NEBULAE
SIZE
SPACE
SPECTRA
SPECTROPHOTOMETRY
STAR EVOLUTION
STARS
ULTRAVIOLET SPECTRA
WHITE DWARF STARS