Temperature-dependent Infrared Optical Constants of Olivine and Enstatite
- Author(s)
- Simon Zeidler, Harald Mutschke, Thomas Posch
- Abstract
Since the Infrared Space Observatory (ISO) mission, it has become clear that dust in circumstellar disks and outflows consists partly of crystalline silicates of pyroxene and olivine type. An exact mineralogical analysis of the dust infrared emission spectra relies on laboratory spectra, which, however, have been mostly measured at room temperature so far. Given that infrared spectral features depend on the thermal excitation of the crystal's vibrational modes, laboratory spectra measured at various (low and high) temperatures, corresponding to the thermal conditions at different distances from the star, can improve the accuracy of such analyses considerably. We have measured the complex refractive index in a temperature range of 10-973 K for one mineral of each of those types of silicate, i.e., for an olivine and an enstatite of typical (terrestrial) composition. Thus, our data extend the temperature range of previous data to higher values and the compositional range to higher iron contents. We analyze the temperature dependence of oscillator frequencies and damping parameters governing the spectral characteristics of the bands and calculate absorption cross-sectional spectra that can be compared with astronomical emission spectra. We demonstrate the usefulness of our new data by comparing spectra calculated for a 100 K dust temperature with the ISO SWS spectrum of IRAS 09425-6040.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- National Astronomical Observatory of Japan, Friedrich-Schiller-Universität Jena
- Journal
- The Astrophysical Journal
- Volume
- 798
- No. of pages
- 18
- ISSN
- 0004-637X
- DOI
- https://doi.org/10.1088/0004-637X/798/2/125
- Publication date
- 01-2015
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy, 103004 Astrophysics
- Keywords
- ASJC Scopus subject areas
- Astronomy and Astrophysics, Space and Planetary Science
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/temperaturedependent-infrared-optical-constants-of-olivine-and-enstatite(24677ecd-6d63-4ed0-84d8-58455a2ca145).html