The AU Mic Debris Disk: Far-Infrared and Submillimeter Resolved Imaging
Journal article, 2015
We present far-infrared and submillimeter maps from the Herschel Space Observatory and the James Clerk Maxwell Telescope of the debris disk host star AU Microscopii. Disk emission is detected at 70, 160, 250, 350, 450, 500, and 850 μm. The disk is resolved at 70, 160, and 450 μm. In addition to the planetesimal belt, we detect thermal emission from AU Mic's halo for the first time. In contrast to the scattered light images, no asymmetries are evident in the disk. The fractional luminosity of the disk is and its milimeter-grain dust mass is (±20%). We create a simple spatial model that reconciles the disk spectral energy distribution as a blackbody of 53 ± 2 K (a composite of 39 and 50 K components) and the presence of small (non-blackbody) grains which populate the extended halo. The best-fit model is consistent with the "birth ring" model explored in earlier works, i.e., an edge-on dust belt extending from 8.8 to 40 AU, but with an additional halo component with an surface density profile extending to the limits of sensitivity (140 AU). We confirm that AU Mic does not exert enough radiation force to blow out grains. For stellar mass-loss rates of 10-100 times solar, compact (zero porosity) grains can only be removed if they are very small; consistently with previous work, if the porosity is 0.9, then grains approaching 0.1 μm can be removed via corpuscular forces (i.e., the stellar wind).
stars: individual (AU Mic)
circumstellar matter
Author
B. C. Matthews
University of Victoria
National Research Council Canada
G. Kennedy
University of Cambridge
B. Sibthorpe
Netherlands Institute for Space Research (SRON)
W. S. Holland
Royal Observatory
University of Edinburgh
M. Booth
Pontificia Universidad Catolica de Chile
P. Kalas
SETI Institute
University of California
M. Macgregor
Harvard-Smithsonian Center for Astrophysics
D. J. Wilner
Harvard-Smithsonian Center for Astrophysics
B. Vandenbussche
KU Leuven
G. Olofsson
AlbaNova University Center
Jadl Blommaert
Flemish Institute for Technological Research
Vrije Universiteit Brussel (VUB)
A. Brandeker
AlbaNova University Center
W. R. F. Dent
Atacama Large Millimeter-submillimeter Array (ALMA)
B. L. D. Vries
Stockholm University
AlbaNova University Center
J. D. Francesco
National Research Council Canada
University of Victoria
Malcolm Fridlund
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
J. R. Graham
University of California
J. S. Greaves
University of St Andrews
A. Heras
European Space Agency (ESA)
M. Hogerheijde
Leiden University
R. J. Ivison
University of Edinburgh
European Southern Observatory (ESO)
E. Pantin
Centre national de la recherche scientifique (CNRS)
G.L. Pilbratt
European Space Agency (ESA)
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 811 2 100- 100Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.1088/0004-637X/811/2/100