A Resolved Millimeter Emission Belt in the AU Mic Debris Disk

TL;DR

This paper reports high-resolution millimeter imaging of the AU Mic debris disk, revealing a distinct dust emission belt at about 35 AU that aligns with the star's scattered light disk, indicating a structured planetesimal reservoir.

Contribution

First millimeter imaging of AU Mic's debris disk identifying a resolved emission belt at 35 AU, linking dust dynamics with the scattered light disk structure.

Findings

Detected a dust emission belt at ~35 AU from AU Mic.

The belt's location aligns with the planetesimal reservoir inferred from optical data.

Strengthens the connection between AU Mic and beta Pic debris disks.

Abstract

We present imaging observations at 1.3 millimeters of the debris disk surrounding the nearby M-type flare star AU Mic with beam size 3 arcsec (30 AU) from the Submillimeter Array. These data reveal a belt of thermal dust emission surrounding the star with the same edge-on geometry as the more extended scattered light disk detected at optical wavelengths. Simple modeling indicates a central radius of ~35 AU for the emission belt. This location is consistent with the reservoir of planetesimals previously invoked to explain the shape of the scattered light surface brightness profile through size-dependent dust dynamics. The identification of this belt further strengthens the kinship between the debris disks around AU Mic and its more massive sister star beta Pic, members of the same ~10 Myr-old moving group.