Tidal Tails From SU Aur's Protoplanetary Disk Caused by Unseen Brown Dwarf?

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

Authors:

de Leon et al

Abstract:

We present new high-resolution (∼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 (∼20 AU) to the star. Within our image, we identify bright emission associated with a disk with a minimum radius of ∼90 AU, an inclination of ∼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.