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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 660755.0, MPI für Astronomie / Publikationen_mpia
Constraints on the radial variation of grain growth in the AS 209 circumstellar disk
Authors:Pérez, L. M.; Carpenter, J. M.; Chandler, C. J.; Isella, A.; Andrews, S. M.; Ricci, L.; Calvet, N.; Corder, S. A.; Deller, A. T.; Dullemond, C. P.; Greaves, J. S.; Harris, R. J.; Henning, T.; Kwon, W.; Lazio, J.; Linz, H.; Mundy, L. G.; Sargent, A. I.; Storm, S.; Testi, L.; Wilner, D. J.
Date of Publication (YYYY-MM-DD):2012
Journal Abbrev.:The Astrophysical Journal Letters
Issue / Number:1
Start Page:id. L17
Audience:Not Specified
Abstract / Description:We present dust continuum observations of the protoplanetary disk surrounding the pre-main sequence star AS 209, spanning more than an order of magnitude in wavelength from 0.88 to 9.8 mm. The disk was observed with sub-arcsecond angular resolution (0.2"-0.5") to investigate radial variations in its dust properties. At longer wavelengths, the disk emission structure is notably more compact, providing model-independent evidence for changes in the grain properties across the disk. We find that physical models which reproduce the disk emission require a radial dependence of the dust opacity \kappa_{\nu}. Assuming that the observed wavelength-dependent structure can be attributed to radial variations in the dust opacity spectral index (\beta), we find that \beta(R) increases from \beta<0.5 at \sim20 AU to \beta>1.5 for R>80 AU, inconsistent with a constant value of \beta\ across the disk (at the 10\sigma\ level). Furthermore, if radial variations of \kappa_{\nu} are caused by particle growth, we find that the maximum size of the particle-size distribution (a_{max}) increases from sub-millimeter-sized grains in the outer disk (R>70 AU) to millimeter and centimeter-sized grains in the inner disk regions (R< 70 AU). We compare our observational constraint on a_{max}(R) with predictions from physical models of dust evolution in proto-planetary disks. For the dust composition and particle-size distribution investigated here, our observational constraints on a_{max}(R) are consistent with models where the maximum grain size is limited by radial drift.
Free Keywords:Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Earth and Planetary Astrophysics
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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