Optical Properties of Iron Silicates in the Infrared to Millimeter as a Function of Temperatures and Wavelength

TL;DR

This study measures the infrared to millimeter optical properties of iron silicate dust analogs across a wide temperature range, providing valuable data for astronomical modeling.

Contribution

It offers comprehensive spectral data and analysis methods for iron silicate optical properties at various temperatures and wavelengths, expanding existing datasets.

Findings

Optical parameters n and k determined for iron silicates.

Temperature-dependent optical properties characterized.

Data spans 5-300 K and 2.5-10,000 micrometers.

Abstract

The Optical Properties of Astronomical Silicates with Infrared Techniques (OPASI-T) program utilizes multiple instruments to provide spectral data over a wide range of temperature and wavelengths. Experimental methods include Vector Network Analyzer (VNA) and Fourier Transform Spectroscopy (FTS) transmission, and reflection/scattering measurements. From this data, we can determine the optical parameters for the index of refraction, \textit{n}, and the absorption coefficient, \textit{k}. The analysis of the laboratory transmittance data for each sample type is based upon different mathematical models, which are applied to each data set according to their degree of coherence. Presented here are results from iron silicate dust grain analogs, in several sample preparations and at temperatures ranging from 5--300 K, across the infrared and millimeter portion of the spectrum (from 2.5--10,000 \mic\ or 4,000--1 \wvn).