THE TW Hya DISK AT 870 {mu}m: COMPARISON OF CO AND DUST RADIAL STRUCTURES

Journal Article · Tue Jan 10 04:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/744/2/162· OSTI ID:22004216

Andrews, Sean M; Wilner, David J; Qi, Chunhua; Rosenfeld, Katherine A; Oeberg, Karin I; Espaillat, Catherine; Ho, Paul T. P. ^[1]; Hughes, A M ^[2]; Birnstiel, T ^[3]; Cieza, Lucas A; Williams, Jonathan P ^[4]; Lin, Shin-Yi ^[5]

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. Department of Astronomy, University of California at Berkeley, 601 Campbell Hall, Berkeley, CA 94720 (United States)
3. Ludwig-Maximilians-Universitaet, University Observatory Munich, Scheinerstrasse 1, D-81679 Munich (Germany)
4. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
5. Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States)

We present high-resolution (0.''3 = 16 AU), high signal-to-noise ratio Submillimeter Array observations of the 870 {mu}m (345 GHz) continuum and CO J = 3 - 2 line emission from the protoplanetary disk around TW Hya. Using continuum and line radiative transfer calculations, these data and the multiwavelength spectral energy distribution are analyzed together in the context of simple two-dimensional parametric disk structure models. Under the assumptions of a radially invariant dust population and gas-to-dust mass ratio, we are unable to simultaneously reproduce the CO and dust observations with model structures that employ either a single, distinct outer boundary or a smooth (exponential) taper at large radii. Instead, we find that the distribution of millimeter-sized dust grains in the TW Hya disk has a relatively sharp edge near 60 AU, contrary to the CO emission (and optical/infrared scattered light) that extends to a much larger radius of at least 215 AU. We discuss some possible explanations for the observed radial distribution of millimeter-sized dust grains and the apparent CO-dust size discrepancy, and suggest that they may be hallmarks of substructure in the dust disk or natural signatures of the growth and radial drift of solids that might be expected for disks around older pre-main-sequence stars like TW Hya.

• OSTI ID: 22004216
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 744; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
DUSTS
ENERGY SPECTRA
MAIN SEQUENCE STARS
PROTOPLANETS
RADIANT HEAT TRANSFER
SIGNAL-TO-NOISE RATIO
SPATIAL DISTRIBUTION