The (sub-)millimeter SED of protoplanetary disks in the outskirts of the Orion nebula cluster

¹ European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany
e-mail: lricci@eso.org
² National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada
³ Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
⁴ Division of Physics, Mathematics and Astronomy, California Institute of Technology, MC 249-17, Pasadena, CA 91125, USA
⁵ Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218, USA
⁶ INAF - Osservatorio Astrofisico di Arcetri, Largo Fermi 5, 50125 Firenze, Italy
⁷ Australia Telescope National Facility, PO Box 76, Epping, NSW 1710, Australia

Received: 20 September 2010
Accepted: 8 October 2010

Abstract

We present the sub-mm/mm SED for a sample of eight young circumstellar disks in the outer regions of the Orion nebula cluster (ONC). New observations were carried out at 2.9 mm with the CARMA array and for one disk, 216-0939, at 3.3 and 6.8 mm with ATCA. By combining these new millimeter data with literature measurements at sub-millimeter wavelengths we investigate grain growth and measure the dust mass in protoplanetary disks in the ONC. These data provide evidence for dust grain growth to at least millimeter-sizes for the first time in a high-mass star-forming region. The obtained range in sub-mm/mm spectral index, namely 1.5–3.2, indicates that for disks in the outskirts of the ONC (projected distance from the cluster center between about 0.4 pc and 1.5 pc) grain growth to mm sizes occurs in the same manner as disks in regions where only low-mass stars form. Finally, in our sample three disks are more massive than about 0.05 M_⊙, confirming that massive disks are present in the outer regions of the Orion nebula.