The PDS 66 Circumstellar Disk as seen in Polarized Light with the Gemini Planet Imager

TL;DR

This paper presents high-resolution polarized light imaging of the PDS 66 circumstellar disk using the Gemini Planet Imager, revealing detailed disk structures including an inner ring, outer ring at 80 AU, and asymmetries, with improved proximity compared to previous observations.

Contribution

First high-resolution polarized light images of PDS 66 disk obtained with GPI, revealing inner disk structures closer to the star than prior observations and analyzing disk asymmetries.

Findings

Detection of the disk down to 0.12'' inner working angle in H band.

Identification of a bright outer ring at 80 AU.

Observation of asymmetries likely caused by shadowing and scattering effects.

Abstract

We present H and K band imaging polarimetry for the PDS 66 circumstellar disk obtained during the commissioning of the Gemini Planet Imager (GPI). Polarization images reveal a clear detection of the disk in to the 0.12'' inner working angle (IWA) in H band, almost 3 times as close to the star as the previous HST observations with NICMOS and STIS (0.35'' effective IWA). The centro-symmetric polarization vectors confirm that the bright inner disk detection is due to circumstellar scattered light. A more diffuse disk extends to a bright outer ring centered at 80 AU. We discuss several physical mechanisms capable of producing the observed ring + gap structure. GPI data confirm enhanced scattering on the East side of the disk which is inferred to be nearer to us. We also detect a lateral asymmetry in the South possibly due to shadowing from material within the inner working angle. This likely corresponds to a temporally variable azimuthal asymmetry observed in HST/STIS coronagraphic imaging.