TW Hya Association Membership and New WISE-detected Circumstellar Disks

TL;DR

This study confirms the presence of circumstellar disks around members of the TW Hydrae Association using WISE infrared data, identifying new disk-bearing members and quantifying the disk fraction among them.

Contribution

The paper identifies new circumstellar disks around low-mass stars in the TW Hydrae Association using WISE data and confirms previous disk detections, providing updated disk fraction statistics.

Findings

New disks detected around TWA 30A, TWA 30B, TWA 31, and TWA 32.

Confirmed existing circumstellar disks with WISE.

Estimated disk fraction of 42% among studied members.

Abstract

We assess the current membership of the nearby, young TW Hydrae Association and examine newly proposed members with the Wide-field Infrared Survey Explorer (WISE) to search for infrared excess indicative of circumstellar disks. Newly proposed members TWA 30A, TWA 30B, TWA 31, and TWA 32 all show excess emission at 12 and 22 \mum providing clear evidence for substantial dusty circumstellar disks around these low-mass, ~8 Myr old stars that were previously shown to likely be accreting from circumstellar material. TWA 30B shows large amounts of self-extinction, likely due to an edge-on disk geometry. We also confirm previously reported circumstellar disks with WISE, and determine a 22 \mum excess fraction of 42+/- 9% based on our results.