Infrared Spectrograph Characterization of a Debris Disk Around an M-Type Star in NGC 2547

We present 5 to 15 μm 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 NGC 2547. The IRS spectrum shows a silicate emission feature, indicating the presence of warm, small, (sub)micron-sized dust grains in the disk. Of the 15 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 μm 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 (h 100 = 2 AU) and extending inward within at least 0.13 AU of the central star. Our analysis shows that the disk is collisionally dominated and is likely a debris disk.