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An Icy Kuiper Belt Around the Young Solar-type Star HD 181327Context. HD 181327 is a young main sequence F5/F6 V star belonging to the Beta Pictoris moving group (age approx.. 12 Myr). It harbors an optically thin belt of circumstellar material at radius approx.. 90 AU, presumed to result from collisions in a population of unseen planetesimals. Aims. We aim to study the dust properties in the belt in details, and to constrain the gas-to-dust ratio. Methods. We obtained far-infrared photometric observations of HD 181327 with the PACS instrument onboard the Herschel Space Observatory, complemented by new 3.2 mm observations carried with the ATCA array. The geometry of the belt is constrained with newly reduced HST/NICMOS scattered light images that allow the degeneracy between the disk geometry and the dust properties to be broken. We then use the radiative transfer code GRaTeR to compute a large grid of models, and we identify the grain models that best reproduce the spectral energy distribution (SED) through a Bayesian analysis. We attempt to detect the oxygen and ionized carbon fine-structure lines with Herschel/PACS spectroscopy, providing observables to our photochemical code ProDiMo. Results. The HST observations confirm that the dust is confined in a narrow belt. The continuum is detected with Herschel/PACS completing nicely the SED in the far-infrared. The disk is marginally resolved with both PACS and ATCA. A medium integration of the gas spectral lines only provides upper limits on the [OI] and [CII] line fluxes.We show that the HD 181327 dust disk consists of micron-sized grains of porous amorphous silicates and carbonaceous material surrounded by an important layer of ice, for a total dust mass of approx.. 0.05 Solar Mass (in grains up to 1 mm). We discuss evidences that the grains consists of fluffy aggregates. The upper limits on the gas atomic lines do not provide unambiguous constraints: only if the PAH abundance is high, the gas mass must be lower than approx. 17 Solar Mass. Conclusions. Despite the weak constraints on the gas disk, the age of HD 181327 and the properties of the dust disk suggest that it has passed the stage of gaseous planets formation. The dust reveals a population of icy planetesimals, similar to the primitive Edgeworth-Kuiper belt, that may be a source for the future delivery of water and volatiles onto forming terrestrial planets.
Document ID
20140010701
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Lebreton, J.
(Grenoble-1 Univ. France)
Augereau, J.-C.
(Grenoble-1 Univ. France)
Thi, W.-F.
(Grenoble-1 Univ. France)
Roberge, A.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Donaldson, J
(Maryland Univ. College Park, MD, United States)
Schneider, G.
(Arizona Univ. Tucson, AZ, United States)
Maddison, S. T.
(Swinburne Univ. of Technology Hawthorn, Australia)
Menard, F.
(Grenoble-1 Univ. France)
Riviere-Marichalar, P.
(Instituto Nacional de Tecnica Aeroespacial Villanueva de la Canada, Spain)
Matthews, G. S.
(Hawaii Univ. Honolulu, HI, United States)
Kamp, I.
(Groningen Rijksuniv. Netherlands)
Pinte, C.
(Grenoble-1 Univ. France)
Dent, W. R. F.
(European Southern Observatory Santiago, Chile)
Barrado, D.
(Instituto Nacional de Tecnica Aeroespacial Villanueva de la Canada, Spain)
Duchene, G.
(Grenoble-1 Univ. France)
Gonzalez, J.-F.
(Lyon-1 Univ. Lyon, France)
Grady C. A.
(Eureka Scientific, Inc. Greenbelt, MD, United States)
Meeus,G.
(Universidad Autonoma de Madrid Spain)
Pantin, E.
(CEA Saclay, Service d'Astrophysique Gif-sur-Yvette, France)
Williams, J. P.
(Hawaii Univ. Honolulu, HI, United States)
Woitke, P.
(Edinburgh Univ. United Kingdom)
Date Acquired
August 15, 2014
Publication Date
March 1, 2012
Publication Information
Publication: Astronomy & Astrophysics
Publisher: Astronomy & Astrophysics
Volume: 539
ISSN: 0004-6361
Subject Category
Astronomy
Report/Patent Number
GSFC-E-DAA-TN11044
Funding Number(s)
CONTRACT_GRANT: NAS5-26555
CONTRACT_GRANT: NNG12PP44P
CONTRACT_GRANT: ANR-2010 BLAN-0505-01
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
HD 181327
radiative transfer
circumstellar matter
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