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Title: SOFIA/FORCAST AND SPITZER/IRAC IMAGING OF THE ULTRACOMPACT H II REGION W3(OH) AND ASSOCIATED PROTOSTARS IN W3

Abstract

We present infrared observations of the ultracompact H II region W3(OH) made by the FORCAST instrument aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA) and by the Spitzer/Infrared Array Camera. We contribute new wavelength data to the spectral energy distribution (SED), which constrains the optical depth, grain size distribution, and temperature gradient of the dusty shell surrounding the H II region. We model the dust component as a spherical shell containing an inner cavity with radius {approx}600 AU, irradiated by a central star of type O9 and temperature {approx}31, 000 K. The total luminosity of this system is 7.1 Multiplication-Sign 10{sup 4} L{sub Sun }. An observed excess of 2.2-4.5 {mu}m emission in the SED can be explained by our viewing a cavity opening or clumpiness in the shell structure whereby radiation from the warm interior of the shell can escape. We claim to detect the nearby water maser source W3 (H{sub 2}O) at 31.4 and 37.1 {mu}m using beam deconvolution of the FORCAST images. We constrain the flux densities of this object at 19.7-37.1 {mu}m. Additionally, we present in situ observations of four young stellar and protostellar objects in the SOFIA field, presumably associated with the W3 molecular cloud.more » Results from the model SED fitting tool of Robitaille et al. suggest that two objects (2MASS J02270352+6152357 and 2MASS J02270824+6152281) are intermediate-luminosity ({approx}236-432 L{sub Sun }) protostars; one object (2MASS J02270887+6152344) is either a high-mass protostar with luminosity 3 Multiplication-Sign 10{sup 3} L{sub Sun} or a less massive young star with a substantial circumstellar disk but depleted envelope; and the other (2MASS J02270743+6152281) is an intermediate-luminosity ({approx}768 L{sub Sun }) protostar nearing the end of its envelope accretion phase or a young star surrounded by a circumstellar disk with no appreciable circumstellar envelope.« less

Authors:
; ; ; ; ;  [1];  [2]; ;  [3];  [4];  [5]
  1. Department of Astronomy, Cornell University, 105 Space Sciences Building, Ithaca, NY 14853 (United States)
  2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 65, Cambridge, MA 02138-1516 (United States)
  3. SOFIA-University Space Research Association, NASA Ames Reseach Center, Mail Stop N211-3, Moffett Field, CA 94035 (United States)
  4. Department of Physics and Astronomy, University of Toledo, Mailstop 111, 2801 West Bancroft Street, Toledo, OH 43606 (United States)
  5. Ithaca College, Physics Department, 264 Center for Natural Sciences, Ithaca, NY 14850 (United States)
Publication Date:
OSTI Identifier:
22092212
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 757; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; CAMERAS; COSMIC DUST; ENERGY SPECTRA; FLUX DENSITY; GRAIN SIZE; H2 REGIONS; INFRARED SPECTRA; LUMINOSITY; MASERS; PROTOSTARS; RADIANT HEAT TRANSFER; STAR ACCRETION; STARS; TEMPERATURE GRADIENTS; WATER

Citation Formats

Hirsch, Lea, Adams, Joseph D., Herter, Terry L., Gull, George E., Henderson, Charles P., Schoenwald, Justin, Hora, Joseph L., De Buizer, James M., Vacca, William, Megeath, S. Thomas, and Keller, Luke D. SOFIA/FORCAST AND SPITZER/IRAC IMAGING OF THE ULTRACOMPACT H II REGION W3(OH) AND ASSOCIATED PROTOSTARS IN W3. United States: N. p., 2012. Web. doi:10.1088/0004-637X/757/2/113.
Hirsch, Lea, Adams, Joseph D., Herter, Terry L., Gull, George E., Henderson, Charles P., Schoenwald, Justin, Hora, Joseph L., De Buizer, James M., Vacca, William, Megeath, S. Thomas, & Keller, Luke D. SOFIA/FORCAST AND SPITZER/IRAC IMAGING OF THE ULTRACOMPACT H II REGION W3(OH) AND ASSOCIATED PROTOSTARS IN W3. United States. https://doi.org/10.1088/0004-637X/757/2/113
Hirsch, Lea, Adams, Joseph D., Herter, Terry L., Gull, George E., Henderson, Charles P., Schoenwald, Justin, Hora, Joseph L., De Buizer, James M., Vacca, William, Megeath, S. Thomas, and Keller, Luke D. Mon . "SOFIA/FORCAST AND SPITZER/IRAC IMAGING OF THE ULTRACOMPACT H II REGION W3(OH) AND ASSOCIATED PROTOSTARS IN W3". United States. https://doi.org/10.1088/0004-637X/757/2/113.
@article{osti_22092212,
title = {SOFIA/FORCAST AND SPITZER/IRAC IMAGING OF THE ULTRACOMPACT H II REGION W3(OH) AND ASSOCIATED PROTOSTARS IN W3},
author = {Hirsch, Lea and Adams, Joseph D. and Herter, Terry L. and Gull, George E. and Henderson, Charles P. and Schoenwald, Justin and Hora, Joseph L. and De Buizer, James M. and Vacca, William and Megeath, S. Thomas and Keller, Luke D.},
abstractNote = {We present infrared observations of the ultracompact H II region W3(OH) made by the FORCAST instrument aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA) and by the Spitzer/Infrared Array Camera. We contribute new wavelength data to the spectral energy distribution (SED), which constrains the optical depth, grain size distribution, and temperature gradient of the dusty shell surrounding the H II region. We model the dust component as a spherical shell containing an inner cavity with radius {approx}600 AU, irradiated by a central star of type O9 and temperature {approx}31, 000 K. The total luminosity of this system is 7.1 Multiplication-Sign 10{sup 4} L{sub Sun }. An observed excess of 2.2-4.5 {mu}m emission in the SED can be explained by our viewing a cavity opening or clumpiness in the shell structure whereby radiation from the warm interior of the shell can escape. We claim to detect the nearby water maser source W3 (H{sub 2}O) at 31.4 and 37.1 {mu}m using beam deconvolution of the FORCAST images. We constrain the flux densities of this object at 19.7-37.1 {mu}m. Additionally, we present in situ observations of four young stellar and protostellar objects in the SOFIA field, presumably associated with the W3 molecular cloud. Results from the model SED fitting tool of Robitaille et al. suggest that two objects (2MASS J02270352+6152357 and 2MASS J02270824+6152281) are intermediate-luminosity ({approx}236-432 L{sub Sun }) protostars; one object (2MASS J02270887+6152344) is either a high-mass protostar with luminosity 3 Multiplication-Sign 10{sup 3} L{sub Sun} or a less massive young star with a substantial circumstellar disk but depleted envelope; and the other (2MASS J02270743+6152281) is an intermediate-luminosity ({approx}768 L{sub Sun }) protostar nearing the end of its envelope accretion phase or a young star surrounded by a circumstellar disk with no appreciable circumstellar envelope.},
doi = {10.1088/0004-637X/757/2/113},
url = {https://www.osti.gov/biblio/22092212}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 757,
place = {United States},
year = {2012},
month = {10}
}