Ultraviolet observations of planetary nebulae.
Abstract
The paper summarizes and discusses the small number of ultraviolet observations that have been made on planetary nebulae. These include a short wave spectrogram of IC 2149 obtained from onboard Soyuz-13, short-wave spectra of NGC 7027 and NGC 7662 obtained from Aerobee rockets, and some OAO-2 and ANS wideband ultraviolet photometry of a number of planetary nebulae. Identifications of individual lines are made. Excess emission radiation in the continuum spectrum of the central star of IC 2149 can be two-photon emission. The amount of two-photon radiation was calculated with a model accounting for three components of the UV continuum: the Balmer continuum of hydrogen, neutral helium, and 2-photon radiation of hydrogen, and the result is in good agreement with observed excess.
- Publication:
-
Planetary Nebulae
- Pub Date:
- 1978
- Bibcode:
- 1978IAUS...76...79G
- Keywords:
-
- Astronomical Models;
- Planetary Nebulae;
- Ultraviolet Astronomy;
- Ultraviolet Photometry;
- Balmer Series;
- Continuous Spectra;
- Emission Spectra;
- H Lines;
- Helium;
- Astrophysics