The Mass of Stirring Bodies in the AU Mic Debris Disk Inferred from Resolved Vertical Structure
Name
Daley_2019_ApJ_875_87.pdf
Description
Published version
Size
2.53 MB
Format
Adobe PDF
Checksum (MD5)
50a4e74b055bc224978f2c2ef6c463a5
Author(s)
Daley, Cail
Hughes, A. Meredith
Carter, Evan S.
Flaherty, Kevin
Lambros, Zachary
Margaret, Pan
Schlichting, Hilke
Chiang, Eugene
Wyatt, Mark
Wilner, David
Date Issued
April 2019
Journal
Astrophysical Journal
Publisher
American Astronomical Society
Citation
Daley, Cail, et al. “The Mass of Stirring Bodies in the AU Mic Debris Disk Inferred from Resolved Vertical Structure.” The Astrophysical Journal 875, 2 (April 2019): 87. © 2019 The American Astronomical Society
Version
Final published version
Abstract
The vertical distribution of dust in debris disks is sensitive to the number and size of large planetesimals dynamically stirring the disk, and is therefore well-suited for constraining the prevalence of otherwise unobservable Uranus and Neptune analogs. Information regarding stirring bodies has previously been inferred from infrared and optical observations of debris disk vertical structure, but theoretical works predict that the small particles traced by short-wavelength observations will be puffed up by radiation pressure, yielding only upper limits. The large grains that dominate the disk emission at millimeter wavelengths are much less sensitive to the effects of stellar radiation or stellar winds, and therefore trace the underlying mass distribution more directly. Here we present ALMA 1.3 mm dust continuum observations of the debris disk around the nearby M star AU Mic. The 3 au spatial resolution of the observations, combined with the favorable edge-on geometry of the system, allows us to measure the vertical thickness of the disk. We report a scale height-to-radius aspect ratio of = -h 0.031+0.004 0.005 between radii of ∼23 au and ∼41 au. Comparing this aspect ratio to a theoretical model of size-dependent velocity distributions in the collisional cascade, we find that the perturbing bodies embedded in the local disk must be larger than about 400 km, and the largest perturbing body must be smaller than roughly 1.8M. These measurements rule out the presence of a gas giant or Neptune analog near the ∼40 au outer edge of the debris ring, but are suggestive of large planetesimals or an Earth-sized planet stirring the dust distribution. Key words: circumstellar matter; planet–disk interactions; planetary systems; stars: individual (AU Mic);
submillimeter: planetary systems
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.3847/1538-4357/AB1074
