Towards the identification of circumstellar hibonite
- Author(s)
- Harald Mutschke, Thomas Posch, Dirk Fabian, Johann M. Dorschner
- Abstract
We have performed IR reflectance measurements on crystalline CaAl12O19 (hibonite) and derived optical constants for both principal directions of the electric field vector relative to the crystallographic c-axis. Based on the resulting dielectric functions, we calculated small particle spectra and found six maxima of the absorption cross section for spherical dust grains at the wavelengths 12.3, 15.9, 21.1, 25.1, 34.4, and 78.7 œm. For nonspherical particles, strong shifting and broadening of the two strongest resonances at 12.3 and 15.9 œm occurs. The signal-to-noise-ratio of ISO spectra of oxygen-rich AGB stars is not sufficient for a definite identification of these bands, even though there is some weak indication of their presence. We propose additional observations to clarify this point.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Friedrich-Schiller-Universität Jena
- Journal
- Astronomy & Astrophysics
- Volume
- 392
- Pages
- 1047-1052
- No. of pages
- 6
- ISSN
- 0004-6361
- DOI
- https://doi.org/10.1051/0004-6361:20021072
- Publication date
- 2002
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/eee27af1-2444-4fe9-ab89-1e76c61e4bd1