Near-Infrared Imaging Polarimetry of Inner Region of GG Tau A Disk

TL;DR

This study used near-infrared polarimetric imaging to reveal complex inner disk structures around the GG Tau A binary system, providing insights into disk morphology and potential planet formation in close binaries.

Contribution

First high-resolution polarized light imaging of GG Tau A's inner disk revealing detailed structures and their implications for binary orbit and planet formation.

Findings

Detected an arc-like structure north of GG Tau Ab.

Constrained GG Tau Ab's disk radius to less than 13 AU.

Suggested the north arc may be a streamer feeding circumstellar disks.

Abstract

By performing non-masked polarization imaging with Subaru/HiCIAO, polarized scattered light from the inner region of the disk around the GG Tau A system was successfully detected in the $H$ band with a spatial resolution of approximately 0.07$\arcsec$, revealing the complicated inner disk structures around this young binary. This paper reports the observation of an arc-like structure to the north of GG Tau Ab and part of a circumstellar structure that is noticeable around GG Tau Aa extending to a distance of approximately 28 AU from the primary star. The speckle noise around GG Tau Ab constrains its disk radius to <13 AU. Based on the size of the circumbinary ring and the circumstellar disk around GG Tau Aa, the semi-major axis of the binary's orbit is likely to be 62 AU. A comparison of the present observations with previous ALMA and near-infrared (NIR) H$_2$ emission observations suggests that the north arc could be part of a large streamer flowing from the circumbinary ring to sustain the circumstellar disks. According to the previous studies, the circumstellar disk around GG Tau Aa has enough mass and can sustain itself for a duration sufficient for planet formation; thus, our study indicates that planets can form within close (separation $\lesssim$ 100 AU) young binary systems.