Infrared Emission from Young Planetary Nebulae
Abstract
Measurements of planetary nebulae in the far infrared, especially from IRAS, are presented and discussed. The dust temperature and intrinsic luminosity are found to vary as the nebula evolves. The source of energy which heats the dust is discussed and it is shown that heating by nebular Lyman alpha is usually insufficient, especially in young nebulae. The problem as to whether the far infrared emission only comes from the ionized region of the nebula or whether the neutral material is also important is argued. The dust mass of the nebula is found to evolve, the dust to gas mass ratio having a high value for very young nebulae. It is argued that the dust is being constantly destroyed. The dust emission spectra of many young nebulae are presented and they are found to fall in three distinct categories. Finally, an estimate of the spatial distribution of young nebulae near the galactic center, as deduced from IRAS measurements, is given.
- Publication:
-
Late Stages of Stellar Evolution
- Pub Date:
- 1987
- DOI:
- 10.1007/978-94-009-3813-7_40
- Bibcode:
- 1987ASSL..132..355P
- Keywords:
-
- Far Infrared Radiation;
- Infrared Sources (Astronomy);
- Planetary Nebulae;
- Cosmic Dust;
- Infrared Astronomy Satellite;
- Lyman Alpha Radiation;
- Spatial Distribution;
- Astrophysics