Ultraviolet spectra of planetary nebulae - X. Physical conditions in the compact planetary nebula SW ST 1.
Abstract
The authors analyse photoelectric visual and ultraviolet observations of the compact planetary nebula Sw St 1. The electron density, determined from the C III λλ1907/1909 line ratio, is Ne = (1.1±0.1)×105cm-3, consistent with the high emission measure and high critical frequency determined from observations of the thermal radio emission. The C/O abundance ratio in the nebula is found to be N(C)/N(O) = 0.72±0.1, i.e. the envelope is oxygen rich, as suggested by the identification of the silicate feature in the 8 - 13 μm infrared spectrum. Difficulties remain in accurately determining the reddening constant to the nebula and its electron temperature.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 1984
- DOI:
- 10.1093/mnras/206.2.293
- Bibcode:
- 1984MNRAS.206..293F
- Keywords:
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- Astronomical Spectroscopy;
- Planetary Nebulae;
- Ultraviolet Astronomy;
- Ultraviolet Spectra;
- Abundance;
- Electron Density Profiles;
- Electron Energy;
- Interstellar Extinction;
- Iue;
- Astronomy