Interstellar extinction and interstellar polarization: old and new models

TL;DR

This paper reviews observational data and models of interstellar extinction and polarization, discussing dust grain properties, alignment mechanisms, and magnetic fields, highlighting ongoing challenges in fully understanding these phenomena.

Contribution

It provides a comprehensive analysis of existing models and observations, emphasizing the complexities and unresolved issues in interpreting interstellar dust effects.

Findings

Dust grain models vary in shape and composition

Grain size distribution and alignment mechanisms are complex

Interpretation of extinction and polarization remains incomplete

Abstract

The review contains an analysis of the observed and model curves of the interstellar extinction and polarization. The observations mainly give information on dust in diffuse and translucent interstellar clouds. The features of various dust grain models including spherical/non-spherical, homogeneous/inhomogeneous particles are discussed. A special attention is devoted to the analysis of the grain size distributions, alignment mechanisms and magnetic field structure in interstellar clouds. It is concluded that the interpretation of interstellar extinction and polarization is not yet complete.