IRAS pointed observations of planetary nebulae.
Abstract
The pointed observations made by IRAS satellite have been analyzed in order to find extended planetary nebulas. Of the 67 nebulas observed only 10 were larger than the IRAS beams. IR data of these nebulas have been compared with optical data. Also a comparison with other IRAS data products has been made. The major part of the IR emission originates in the ionized region. No evidence for weak extended IR haloes could be found. The IR emission has a single temperature and its brightness drops suddenly at the IR edge. In BD + 30 3639 and NGC 6543 there is evidence for IF emission which envelopes the ionized region. This dust could be a remnant of the progenitor shell. IR sizes have been determined by model fits. The calculations indicate a mass loss rate in dust between 10 to the -7th and 10 to the -6th solar masses/yr, which is caused by the onset of some 'superwind'. The models support the existence of a temperature gradient in NGC 6543 and BD + 30 3639.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 1988
- Bibcode:
- 1988A&A...202..203L
- Keywords:
-
- Emission Spectra;
- Infrared Astronomy Satellite;
- Infrared Radiation;
- Planetary Nebulae;
- Flux Density;
- Lyman Alpha Radiation;
- Temperature Gradients;
- Astrophysics