HD 169142 in the eyes of ZIMPOL/SPHERE

TL;DR

This paper presents high-resolution polarimetric imaging of the HD 169142 protoplanetary disc, revealing detailed structures, gaps, and potential signs of planet-disc interactions, enhancing understanding of disc morphology and planet formation processes.

Contribution

The study provides the first high-resolution polarimetric images of HD 169142's disc, uncovering new substructures and features indicative of planet-disc interactions.

Findings

Inner hole and bright ring with substructures identified

Elliptical gap from 29 to 55 au observed

Signs of planet-disc interactions such as small-scale structures and shadows

Abstract

We present new data of the protoplanetary disc surrounding the Herbig Ae/Be star HD 169142 obtained in the very broad-band (VBB) with the Zurich imaging polarimeter (ZIMPOL), a sub-system of the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE) at the Very Large Telescope (VLT). Our Polarimetric Differential Imaging (PDI) observations probe the disc as close as 0.03" (3.5au) to the star and are able to trace the disc out to ~1.08" (~126au). We find an inner hole, a bright ring bearing substructures around 0.18" (21au), and an elliptically shaped gap stretching from 0.25" to 0.47" (29-55au). Outside of 0.47", the surface brightness drops off, discontinued only by a narrow annular brightness minimum at ~0.63"-0.74" (74-87au). These observations confirm features found in less-well resolved data as well as reveal yet undetected indications for planet-disc interactions, such as small-scale structures, star-disk offsets, and potentially moving shadows.