High-Resolution Near-Infrared Images of the T Tauri Binary System XZ Tauri

Abstract

We present a high-resolution (∼0.1'' = 14AU) H-band image of XZ Tau, a 0.3''-separated classical T Tauri binary system, taken with the Coronagraphic Imager with Adaptive Optics (CIAO) on the Subaru Telescope. We found a scattered light nebula extending to ∼2.4'' from the secondary, XZ Tau S, in the northeast region of the binary. Its surface brightness is ∼16.2 mag arcsec^-2 in the H-band, and decreases as r^-1.6±0.1. Combined with the HST/ACS polarimetric images and the [Fe II] λ1.644μm spectra taken with the Infrared Camera and Spectrograph (IRCS) on the Subaru Telescope, the elongated structure is identified as a wall of a cavity blown by the previously known blueshifted outflow. By a comparison with previous measurements, we estimated that the orbital period is 1010±260 yr and the total mass of the binary is 0.62±0.36M_odot. The observed H-band magnitudes of both the primary and the secondary varied by as much as 1 mag over this decade. These H-band inconstancies may arise from a variable accretion rate and changing extinction toward each component.