Near-Infrared Polarimetry of the GG Tauri A Binary System

TL;DR

This study presents high-resolution near-infrared polarized imaging of the GG Tau A binary system, revealing disk structures, dust grain properties, and orbital dynamics through detailed observations and modeling.

Contribution

First near-infrared polarized image of GG Tau A with disk modeling, showing dust grain properties and orbital motion insights.

Findings

Disk scattering indicates small dust grains on the disk surface.

The circumbinary disk's gap orbits anti-clockwise, material orbits clockwise.

Binary orbit parameters are consistent over 20 years with a = 33.4 AU and e = 0.34.

Abstract

A high angular resolution near-infrared polarized-intensity image of the GG Tau A binary system was obtained with the Subaru Telescope. The image shows the circumbinary disk scattering the light from the central binary. The azimuthal profile of the polarized intensity of the circumbinary disk is roughly reproduced by a simple disk model with the Henyey-Greenstein function and the Rayleigh function, indicating small dust grains at the surface of the disk. Combined with a previous observation of the circumbinary disk, our image indicates that the gap structure in the circumbinary disk orbits anti-clockwise, while material in the disk orbit clockwise. We propose a shadow of material located between the central binary and the circumbinary disk. The separations and position angles of the stellar components of the binary in the past 20 years are consistent with the binary orbit with a = 33.4 AU and e = 0.34.