Probing the Terrestrial Regions of Planetary Systems: Warm Debris Disks with Emission Features

Abstract

Observations of debris disks allow for the study of planetary systems, even where planets have not been detected. However, debris disks are often only characterized by unresolved infrared excesses that resemble featureless blackbodies, and the location of the emitting dust is uncertain due to a degeneracy with the dust grain properties. Here we characterize the Spitzer IRS spectra of 22 debris disks exhibiting 10 micron silicate emission features. Such features arise from small warm dust grains, and their presence can significantly constrain the orbital location of the emitting debris. We find that these features can be explained by the presence of an additional dust component in the terrestrial zones of the planetary systems, i.e. an exozodiacal belt. Aside from possessing exozodiacal dust, these debris disks are not particularly unique; their minimum grain sizes are consistent with the blowout sizes of their systems, and their brightnesses are comparable to those of featureless warm debris disks. These disks are in systems with a range of ages, although the older systems with features are found only around A-type stars. The features in young systems may be signatures of terrestrial planet formation. Analyzing the spectra of unresolved debris disks with emission features may be one of the simplest and most accessible ways to study the terrestrial regions of planetary systems.

Accepted for publication in ApJ

References in corpus (22)

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Cited by in corpus (10)

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• A Direct Imaging Survey of Spitzer detected debris disks: Occurrence of giant planets in dusty systems
• Debris Distribution in HD 95086 - A Young Analog of HR 8799
• A gap in HD 92945's broad planetesimal disc revealed by ALMA
• Spatially resolved imaging of the inner Fomalhaut disk using JWST/MIRI
• Is there more than meets the eye? Presence and role of submicron grains in debris discs
• What Sets the Radial Locations of Warm Debris Disks?
• A PR drag origin for the Fomalhaut disk's pervasive inner dust: constraints on collisional strengths, icy composition, and embedded planets
• Abundant sub-micron grains revealed in newly discovered extreme debris discs
• V488 Per revisited: no strong mid-infrared emission features and no evidence for stellar/sub-stellar companions