A calculation of infrared spectra from dust in planetary nebulae.
Abstract
Summary. In this paper, we calculate grain equilibrium temperatures and the infrared continuum for several planetary nebulae; the heat balance equation is handled rigorously. The dust grains are taken to be either graphite, or ice covered graphite cores. The dust is taken to be either in: (1) the outer H I region, or (2) the H ii region. Comparison with observation suggests that a combination of these two cases would be more realistic. A small fraction (l0- - 10 ) of the resonantly trapped Ly oc radiation in the H ii region is absorbed by grains situated there, and gives rise to the observed IR excesses between 4 and 12 The remaining part of Ly oc is absorbed by the colder grains lying in the outer H I region and may explain the IR fluxes observed beyond 15 . Key words: planetary nebulae - dust infrared excess
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 1974
- Bibcode:
- 1974A&A....34..141B