IRS Characterization of a Debris Disk around an M-type star in NGC2547

TL;DR

This study presents the first mid-infrared spectrum of a debris disk around an M-type star, revealing silicate emission and detailed disk properties through spectral analysis and modeling.

Contribution

It provides the first observed mid-infrared spectrum and silicate emission measurement for a debris disk around an M-type star, advancing understanding of such disks.

Findings

Detected silicate emission indicating warm, small dust grains

Disk is very flat and extends inward within 0.13AU of the star

Disk is collisionally dominated and likely a debris disk

Abstract

We present 5 to 15 micron Spitzer Infrared Spectrograph (IRS) low resolution spectral data of a candidate debris disk around an M4.5 star identified as a likely member of the ~40 Myr old cluster NGC2547. The IRS spectrum shows a silicate emission feature, indicating the presence of warm, small, (sub)micron-sized dust grains in the disk. Of the fifteen previously known candidate debris disks around M-type stars, the one we discuss in this paper is the first to have an observed mid-infrared spectrum and is also the first to have measured silicate emission. We combined the IRS data with ancillary data (optical, JHKs, and Spitzer InfraRed Array Camera and 24 micron data) to build the spectral energy distribution (SED) of the source. Monte Carlo radiation transfer modeling of the SED characterized the dust disk as being very flat (h100=2AU) and extending inward within at least 0.13AU of the central star. Our analysis shows that the disk is collisionally dominated and is likely a debris disk.