Near-Infrared Imaging Polarimetry of HD142527

TL;DR

This study uses near-infrared polarimetric imaging to analyze the disk structure and dust properties of HD 142527, revealing polarization patterns and features linked to planet formation processes.

Contribution

First polarimetric imaging at H and Ks bands of HD 142527's disk, providing detailed polarization degree maps and insights into dust grain properties and disk morphology.

Findings

Polarization degree varies between 10% and 25%.

Dust is composed of compact particles up to a few microns.

Identified nulls in emission correlate with sub-millimeter features.

Abstract

HD 142527 is a pre-transition disk with strong evidence for on-going planet formation. Recent observations show a disrupted disk with spiral arms, a dust-depleted inner cavity and the possible presence of gas streams driving gas from the outer disk towards the central star. We aim to derive the morphology of the disk, as well as the distribution and properties of the dust at its surface. We have obtained polarized differential images of HD 142527 at $H$ and $Ks$ bands with NaCo at the VLT. Combining these images with classical PSF-subtraction, we are able to derive the polarization degree of this disk. At $H$ band the polarization degree of the disk varies between 10% and 25%. This result cannot be reproduced by dust distributions containing highly porous material. The polarization is better matched by distributions of compact particles, with maximum sizes at least up to a few microns, in agreement with previous observations. We also observe two regions of low emission (nulls) in total and in polarized intensity. In particular, one of these nulls is at roughly the same position as the maximum of the horse-shoe shape observed in sub-millimeter continuum emission ALMA Band-7 (345 GHz) observations. We discuss the possible link between both features.