# Modelling the mid-infrared polarization in dust around young stars

## TL;DR

This study models mid-infrared polarization in dust around young stars to detect silicon carbide, revealing its possible presence in the outer disk/envelope of one star through comparison with polarimetric observations.

## Contribution

It introduces a novel approach combining DDA and EMA methods to model dust polarization and identify SiC in protoplanetary disks, enhancing understanding of dust composition around young stars.

## Key findings

- Possible detection of SiC in the outer disk of one star
- Modeling matches observed polarization features at 10 μm
- Provides insights into dust composition in protoplanetary environments

## Abstract

The presence of crystalline silicates has been detected in the circumstellar environment of several young stars in the recent past and there is evidence of silicon carbide (SiC) detection in the envelope of pre-main sequence star SVS13. In this work, we have attempted to probe the presence of SiC in the dust around protoplanetary disks in a sample of young stars. We have modelled the linear polarization of composite dust grains in the mid-infrared (MIR: 8--13 $\mu$m) using silicates as the host with various inclusions of SiC and graphites using the Discrete Dipole Approximation (DDA) and the Effective Medium Approximation (EMA) T-Matrix methods. We have then compared our modelling results with polarimetric observations made in the protoplanetary disks surrounding two Herbig Be stars and one T-Tauri star with particular emphasis towards the 10 $\mu$m silicate feature using CanariCam mounted over the Gran Telescopio Canarias (GTC). We report the possible existence of SiC in the outer disk/envelope around one star in our sample which has been interpreted based on the shape, size, composition and fraction of inclusions by volume in our dust grain models.