A study of frequency and size distribution dependence of extinction for astronomical silicate and graphite grains

TL;DR

This paper develops analytical models for the extinction spectra of interstellar silicate and graphite grains, considering their size distribution and frequency dependence, aiding in understanding dust grain properties.

Contribution

It introduces parametrized analytical expressions for extinction spectra of silicate and graphite grains based on size distribution and frequency, extending previous models.

Findings

Analytic expressions for UV and far-UV extinction spectra.

Identification of valid size range parameters.

Framework applicable to interstellar dust modeling.

Abstract

It is generally agreed that interstellar dust grains consist of two main components, namely, silicates and graphites. Some models, like MRN model, assume these grains to be homogeneous spheres following a power law size distribution. This paper presents, in the framework of Mie theory, a parametrization of extinction spectrum curves of the silicates and the graphites separately in terms of frequency and the minimum and maximum of sizes in the distribution. Analytic expressions in ultraviolet and far-ultraviolet are presented for both types of grains.The values of maximum and minimum sizes for which these equations are valid have been identified. These equations can be useful in a number of situations involving silicate and graphite grains.