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Title: The SOFIA Massive (SOMA) Star Formation Survey. I. Overview and First Results

Abstract

We present an overview and first results of the Stratospheric Observatory For Infrared Astronomy Massive (SOMA) Star Formation Survey, which is using the FORCAST instrument to image massive protostars from ∼10 to 40 μ m. These wavelengths trace thermal emission from warm dust, which in Core Accretion models mainly emerges from the inner regions of protostellar outflow cavities. Dust in dense core envelopes also imprints characteristic extinction patterns at these wavelengths, causing intensity peaks to shift along the outflow axis and profiles to become more symmetric at longer wavelengths. We present observational results for the first eight protostars in the survey, i.e., multiwavelength images, including some ancillary ground-based mid-infrared (MIR) observations and archival Spitzer and Herschel data. These images generally show extended MIR/FIR emission along directions consistent with those of known outflows and with shorter wavelength peak flux positions displaced from the protostar along the blueshifted, near-facing sides, thus confirming qualitative predictions of Core Accretion models. We then compile spectral energy distributions and use these to derive protostellar properties by fitting theoretical radiative transfer models. Zhang and Tan models, based on the Turbulent Core Model of McKee and Tan, imply the sources have protostellar masses m {sub *} ∼ 10–50more » M {sub ⊙} accreting at ∼10{sup −4}–10{sup −3} M {sub ⊙} yr{sup −1} inside cores of initial masses M {sub c} ∼ 30–500 M {sub ⊙} embedded in clumps with mass surface densities Σ{sub cl} ∼ 0.1–3 g cm{sup −2}. Fitting the Robitaille et al. models typically leads to slightly higher protostellar masses, but with disk accretion rates ∼100× smaller. We discuss reasons for these differences and overall implications of these first survey results for massive star formation theories.« less

Authors:
;  [1]; ; ; ;  [2];  [3];  [4];  [5]
  1. SOFIA-USRA, NASA Ames Research Center, MS 232-12, Moffett Field, CA 94035 (United States)
  2. Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States)
  3. Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile)
  4. INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy)
  5. Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter St, Madison, WI 53706 (United States)
Publication Date:
OSTI Identifier:
22663453
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 843; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; ASTRONOMY; DENSITY; DUSTS; EMISSION; ENERGY SPECTRA; FAR INFRARED RADIATION; INTERMEDIATE INFRARED RADIATION; MASS; PROTOSTARS; RADIANT HEAT TRANSFER; STARS; SURFACES; SYMMETRY; WAVELENGTHS

Citation Formats

De Buizer, James M., Shuping, Ralph, Liu, Mengyao, Tan, Jonathan C., Staff, Jan E., Tanaka, Kei E. I., Zhang, Yichen, Beltrán, Maria T., and Whitney, Barbara. The SOFIA Massive (SOMA) Star Formation Survey. I. Overview and First Results. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA74C8.
De Buizer, James M., Shuping, Ralph, Liu, Mengyao, Tan, Jonathan C., Staff, Jan E., Tanaka, Kei E. I., Zhang, Yichen, Beltrán, Maria T., & Whitney, Barbara. The SOFIA Massive (SOMA) Star Formation Survey. I. Overview and First Results. United States. doi:10.3847/1538-4357/AA74C8.
De Buizer, James M., Shuping, Ralph, Liu, Mengyao, Tan, Jonathan C., Staff, Jan E., Tanaka, Kei E. I., Zhang, Yichen, Beltrán, Maria T., and Whitney, Barbara. Sat . "The SOFIA Massive (SOMA) Star Formation Survey. I. Overview and First Results". United States. doi:10.3847/1538-4357/AA74C8.
@article{osti_22663453,
title = {The SOFIA Massive (SOMA) Star Formation Survey. I. Overview and First Results},
author = {De Buizer, James M. and Shuping, Ralph and Liu, Mengyao and Tan, Jonathan C. and Staff, Jan E. and Tanaka, Kei E. I. and Zhang, Yichen and Beltrán, Maria T. and Whitney, Barbara},
abstractNote = {We present an overview and first results of the Stratospheric Observatory For Infrared Astronomy Massive (SOMA) Star Formation Survey, which is using the FORCAST instrument to image massive protostars from ∼10 to 40 μ m. These wavelengths trace thermal emission from warm dust, which in Core Accretion models mainly emerges from the inner regions of protostellar outflow cavities. Dust in dense core envelopes also imprints characteristic extinction patterns at these wavelengths, causing intensity peaks to shift along the outflow axis and profiles to become more symmetric at longer wavelengths. We present observational results for the first eight protostars in the survey, i.e., multiwavelength images, including some ancillary ground-based mid-infrared (MIR) observations and archival Spitzer and Herschel data. These images generally show extended MIR/FIR emission along directions consistent with those of known outflows and with shorter wavelength peak flux positions displaced from the protostar along the blueshifted, near-facing sides, thus confirming qualitative predictions of Core Accretion models. We then compile spectral energy distributions and use these to derive protostellar properties by fitting theoretical radiative transfer models. Zhang and Tan models, based on the Turbulent Core Model of McKee and Tan, imply the sources have protostellar masses m {sub *} ∼ 10–50 M {sub ⊙} accreting at ∼10{sup −4}–10{sup −3} M {sub ⊙} yr{sup −1} inside cores of initial masses M {sub c} ∼ 30–500 M {sub ⊙} embedded in clumps with mass surface densities Σ{sub cl} ∼ 0.1–3 g cm{sup −2}. Fitting the Robitaille et al. models typically leads to slightly higher protostellar masses, but with disk accretion rates ∼100× smaller. We discuss reasons for these differences and overall implications of these first survey results for massive star formation theories.},
doi = {10.3847/1538-4357/AA74C8},
journal = {Astrophysical Journal},
number = 1,
volume = 843,
place = {United States},
year = {Sat Jul 01 00:00:00 EDT 2017},
month = {Sat Jul 01 00:00:00 EDT 2017}
}
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