Near-IR High-Resolution Imaging Polarimetry of the SU Aur Disk: Clues for Tidal Tails?

TL;DR

This study uses high-resolution near-infrared imaging polarimetry to reveal complex disk structures and potential tidal tails around the T Tauri star SU Aur, suggesting possible interactions or outflow phenomena.

Contribution

First high-resolution polarimetric imaging of SU Aur's disk revealing asymmetric features and extended tails, indicating possible tidal interactions or outflow activity.

Findings

Detected a disk with a radius of ~90 AU and asymmetries.

Identified asymmetric tail structures extending up to 350 AU.

Suggested tails may result from tidal encounters or outflows.

Abstract

We present new high-resolution ($\sim$0\farcs09) $H$-band imaging observations of the circumstellar disk around the T Tauri star SU Aur. Our observations with Subaru-HiCIAO have revealed the presence of scattered light as close as 0\farcs15 ($\sim$20 AU) to the star. Within our image, we identify bright emission associated with a disk with a minimum radius of $\sim$90 AU, an inclination of $\sim$35\degr from the plane of the sky, and an approximate P.A. of 15\degr for the major axis. We find a brightness asymmetry between the northern and southern sides of the disk due to a non-axisymmetric disk structure. We also identify a pair of asymmetric tail structures extending east and west from the disk. The western tail extends at least 2\farcs5 (350 AU) from the star, and is probably associated with a reflection nebula previously observed at optical and near-IR wavelengths. The eastern tail extends at least 1\arcsec (140 AU) at the present signal-to-noise. These tails are likely due to an encounter with an unseen brown dwarf, but our results do not exclude the explanation that these tails are outflow cavities or jets.