Circumnebular neutral hydrogen in planetary nebulae

Journal Article · Thu Mar 01 04:00:00 EST 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168489· OSTI ID:7135427

Taylor, A R; Gussie, G T; Pottasch, S R ^[1]

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1. Calgary Univ. (Canada) Groningen, Rijksuniversiteit (Netherlands)

Centimeter line observations of six compact planetary nebulae are reported. Circumnebular atomic hydrogen absorption has been observed in NGC 6790, NGC 6886, IC 418, IC 5117, and BD +30 deg 3639, while H I was not observed to a high upper limit in NGC 6741. Hydrogen was also detected in emission from BD +30 deg 3639. The expansion velocities of the circumnebular envelopes are similar to the expansion velocities observed for the ionized nebula. The optical depth of circumnebular H I appears to decrease with increasing linear radius of the ionized nebulae, indicating that these nebulae are ionization bounded and that the amount of atomic hydrogen decreases as young nebulas evolve. 28 refs.

• OSTI ID: 7135427
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 351; 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
CHEMICAL COMPOSITION
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
EXPANSION
H1 REGIONS
IONIZATION
NEBULAE
PLANETARY NEBULAE
RADIATIONS
RADIOWAVE RADIATION
SPECTRA
STAR EVOLUTION