Observations of the emission nebulae S 188 and S 274 at 2.7 and 5 GHz.
Abstract
The two morphologically similar nebulae S188 and S274 have been mapped in the radio continuum at 2.7 and 5 GHz. The sources seem to have thermal spectra and the new data effectively rule out that either or both are shell-type supernova remnants. It is demonstrated that a number of distance-independent parameters of the nebulae are closely similar and all present evidence indicates that both are old planetary nebulae. On this hypothesis, the distances of the nebulae are estimated from the radio data. A number of other parameters of the objects are considered in the light of these distances.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 1984
- Bibcode:
- 1984A&A...137..291S
- Keywords:
-
- Astronomical Spectroscopy;
- Galactic Radiation;
- Planetary Nebulae;
- Radio Sources (Astronomy);
- Supernova Remnants;
- Astronomical Maps;
- Radio Spectra;
- Astrophysics