Truncated Disks in TW Hya Association Multiple Star Systems

TL;DR

This study uses high-resolution submillimeter observations and modeling to reveal that circumstellar disks in the TW Hya association are truncated and aligned with their binary orbits, consistent with tidal interaction theories.

Contribution

First detailed high-resolution imaging and modeling of truncated disks in the TW Hya association, confirming tidal truncation effects in multiple star systems.

Findings

Disks are localized around specific stellar components with no circum-system material.

HD 98800 B disk is truncated at 3.5 AU, extending to 10-15 AU.

Hen 3-600 A disk has an inner edge at 1 AU and extends to 15-25 AU.

Abstract

We present high angular resolution (down to 0.3" = 13 AU in diameter) Submillimeter Array observations of the 880 micron (340 GHz) thermal continuum emission from circumstellar dust disks in the nearby HD 98800 and Hen 3-600 multiple star systems. In both cases, the dust emission is resolved and localized around one stellar component - the HD 98800 B and Hen 3-600 A spectroscopic binaries - with no evidence for circum-system material. Using two-dimensional Monte Carlo radiative transfer calculations, we compare the SMA visibilities and broadband spectral energy distributions with truncated disk models to empirically locate the inner and outer edges of both disks. The HD 98800 B disk appears to be aligned with the spectroscopic binary orbit, is internally truncated at a radius of 3.5 AU, and extends to only 10-15 AU from the central stars. The Hen 3-600 A disk is slightly larger, with an inner edge at 1 AU and an outer radius of 15-25 AU. These inferred disk structures compare favorably with theoretical predictions of their truncation due to tidal interactions with the stellar companions.