Dust Grain Evolution in Spatially Resolved T Tauri Binaries

TL;DR

This study investigates dust grain growth in T Tauri binary star systems using spatially resolved spectroscopy, revealing that shared properties influence dust evolution and suggesting binarity impacts grain size distribution.

Contribution

It provides the first spatially resolved spectroscopic analysis of dust evolution in close T Tauri binaries, highlighting the role of shared properties and binarity in grain growth.

Findings

Binary stars have more similar silicate features than random singles.

Secondary stars tend to have smaller grains than primaries.

Shared properties influence dust grain evolution in binaries.

Abstract

Core-accretion planet formation begins in protoplanetary disks with the growth of small, ISM dust grains into larger particles. The progress of grain growth, which can be quantified using 10 micron silicate spectroscopy, has broad implications for the final products of planet formation. Previous studies have attempted to correlate stellar and disk properties with the 10 micron silicate feature in an effort to determine which stars are efficient at grain growth. Thus far there does not appear to be a dominant correlated parameter. In this paper, we use spatially resolved adaptive optics spectroscopy of 9 T Tauri binaries as tight as 0.25" to determine if basic properties shared between binary stars, such as age, composition, and formation history, have an effect on dust grain evolution. We find with 90-95% confidence that the silicate feature equivalent widths of binaries are more similar than those of randomly paired single stars, implying that shared properties do play an important role in dust grain evolution. At lower statistical significance, we find with 82% confidence that the secondary has a more prominent silicate emission feature (i.e., smaller grains) than the primary. If confirmed by larger surveys, this would imply that spectral type and/or binarity are important factors in dust grain evolution.