The structures of and distances to BD +30 deg 3639 and NGC 6572

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

DOI:https://doi.org/10.1086/168005· OSTI ID:7000453

Masson, C R ^[1]

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1. California Institute of Technology, Pasadena (USA)

New high-resolution VLA maps of the dense planetary nebulae BD +30 deg 3639 and NGC 6572 are presented. A prolate-ellipsoidal model was used to account for the appearance of these nebulae in quantitative detail, along with a recently developed technique of measuring expansion motions with the VLA to determine the distances to these dense planetary nebulae. Both nebulae have significantly greater distances than previously expected: 2.8 + 47.0 or - 1.2 kpc is the estimated distance to BD +30 deg 3639, and 1.7 + 6.1 or - 0.8 kpc is the one to NGC 6572. The upward revision of the distance, has important implications for the state of the nebulae, reducing their calculated densities and increasing their luminosities. The discrepancy between the new distances for dense nebulae and those calculated from statistical assumptions casts some doubt on the use of statistical methods for such objects. Luminous, optically thick nebulae may have been systematically undercounted, thus affecting studies of mass return to the interstellar medium and of the evolution of central stars. 30 refs.

• OSTI ID: 7000453
• 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
CALCULATION METHODS
DENSITY
DISTANCE
EXPANSION
FLUX DENSITY
INTERSTELLAR SPACE
LUMINOSITY
MATHEMATICAL MODELS
NEBULAE
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLANETARY NEBULAE
RADIANT FLUX DENSITY
SPACE
STAR EVOLUTION
VELOCITY