A COMPACT CONCENTRATION OF LARGE GRAINS IN THE HD 142527 PROTOPLANETARY DUST TRAP
- Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile)
- School of Physical, Environmental and Mathematical Sciences, UNSW Canberra, P.O. Box 7916, Canberra BC 2610 (Australia)
- Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, VIC 3122 (Australia)
- National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States)
- Millennium Nucleus “Protoplanetary Disks,” Santiago (Chile)
- Leiden Observatory, Leiden University, P.O. Box 9513, 2300RA Leiden (Netherlands)
- Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)
- UMI-FCA, CNRS/INSU France (UMI 3386), at Departamento de Astronomía, Universidad de Chile, Santiago (Chile)
- Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441, Santiago (Chile)
A pathway to the formation of planetesimals, and eventually giant planets, may occur in concentrations of dust grains trapped in pressure maxima. Dramatic crescent-shaped dust concentrations have been seen in recent radio images at submillimeter wavelengths. These disk asymmetries could represent the initial phases of planet formation in the dust trap scenario, provided that grain sizes are spatially segregated. A testable prediction of azimuthal dust trapping is that progressively larger grains should be more sharply confined and should follow a distribution that is markedly different from the gas. However, gas tracers such as {sup 12}CO and the infrared emission from small grains are both very optically thick where the submillimeter continuum originates, so previous observations have been unable to test the trapping predictions or to identify compact concentrations of larger grains required for planet formation by core accretion. Here we report multifrequency observations of HD 142527, from 34 to 700 GHz, that reveal a compact concentration of grains approaching centimeter sizes, with a few Earth masses, embedded in a large-scale crescent of smaller, submillimeter-sized particles. The emission peaks at wavelengths shorter than ∼1 mm are optically thick and trace the temperature structure resulting from shadows cast by the inner regions. Given this temperature structure, we infer that the largest dust grains are concentrated in the 34 GHz clump. We conclude that dust trapping is efficient enough for grains observable at centimeter wavelengths to lead to compact concentrations.
- OSTI ID:
- 22518789
- Journal Information:
- Astrophysical Journal, Vol. 812, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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