The SPITZER Infrared Spectrograph Survey of protoplanetary Disks in Orion A. I. Disk Properties
Abstract
We present our investigation of 319 Class II objects in Orion A observed by Spitzer/IRS. We also present the follow-up observations of 120 of these Class II objects in Orion A from the Infrared Telescope Facility/SpeX. We measure continuum spectral indices, equivalent widths, and integrated fluxes that pertain to disk structure and dust composition from IRS spectra of Class II objects in Orion A. We estimate mass accretion rates using hydrogen recombination lines in the SpeX spectra of our targets. Utilizing these properties, we compare the distributions of the disk and dust properties of Orion A disks with those of Taurus disks with respect to position within Orion A (Orion Nebular Cluster [ONC] and L1641) and with the subgroups by the inferred radial structures, such as transitional disks (TDs) versus radially continuous full disks (FDs). Our main findings are as follows. (1) Inner disks evolve faster than the outer disks. (2) The mass accretion rates of TDs and those of radially continuous FDs are statistically significantly displaced from each other. The median mass accretion rate of radially continuous disks in the ONC and L1641 is not very different from that in Taurus. (3) Less grain processing has occurred in the disks in the ONC compared to those in Taurus, based on analysis of the shape index of the 10 μm silicate feature (F_(11.3)/F_(9.8)). (4) The 20–31 μm continuum spectral index tracks the projected distance from the most luminous Trapezium star, θ^1 Ori C. A possible explanation is UV ablation of the outer parts of disks.
Additional Information
© 2016 American Astronomical Society. Received 2015 June 19; revised 2016 April 11; accepted 2016 April 12; published 2016 September 2. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract 1407. Support for this work was provided by NASA through Contract Number 1257184 issued by JPL/Caltech, and Cornell subcontracts 31419-5714 to the University of Rochester. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France. This research has made use of the VizieR catalog access tool, CDS, Strasbourg, France. The original description of the VizieR service was published in A&AS, 143, 23. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the US Department of Energy Office of Science. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration, including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, University of Cambridge, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University. The UKIDSS project is defined in Lawrence et al. (2007). UKIDSS uses the UKIRT Wide Field Camera (WFCAM; Casali et al. 2007). The photometric system is described in Hewett et al. (2006), and the calibration is described in Hodgkin et al. (2009). The pipeline processing and science archive are described in P. G. J. Irwin et al. (in preparation) and Hambly et al. (2008). K.H.K. was a visiting Astronomer at the Infrared Telescope Facility, which is operated by the University of Hawaii under contract NNH14CK55B with the National Aeronautics and Space Administration. Facilities: Spitzer (IRS) - , IRTF (SpeX) - .Attached Files
Published - apjs_226_1_8.pdf
Submitted - 1604.07907v1.pdf
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Additional details
- Eprint ID
- 70173
- Resolver ID
- CaltechAUTHORS:20160906-103711484
- 1407
- NASA
- 1257184
- NASA
- 31419-5714
- NASA
- NSF
- NASA/JPL/Caltech
- Alfred P. Sloan Foundation
- NNH14CK55B
- NASA
- Participating Institutions
- Department of Energy (DOE)
- Created
-
2016-09-06Created from EPrint's datestamp field
- Updated
-
2021-11-11Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)