Low-temperature free-free emission: infrared excesses in Be stars.
Abstract
We discuss the possibility that the infrared emission observed for certain Ae and Be stars may be produced by low temperature free-free processes in the circumstellar region. The problems associated with H - are discussed and it is shown that, for an optically thin sphere, if H - free-free processes dominate in the infrared, then one ought to see a strong free-bound continuum in the visible superposed on the stellar continuum. The same arguments can be applied to the electronproton process. Thus we are left with the fact that a free-free-like opacity fits the observed infrared fluxes but without a corresponding physical picture of the specific mechanism. Subject headings: Be stars - circumstellar shells - infrared sources - opacities
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1973
- DOI:
- 10.1086/152095
- Bibcode:
- 1973ApJ...181..833M