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Title: IN-SYNC. II. VIRIAL STARS FROM SUBVIRIAL CORES—THE VELOCITY DISPERSION OF EMBEDDED PRE-MAIN-SEQUENCE STARS IN NGC 1333

The initial velocity dispersion of newborn stars is a major unconstrained aspect of star formation theory. Using near-infrared spectra obtained with the APOGEE spectrograph, we show that the velocity dispersion of young (1-2 Myr) stars in NGC 1333 is 0.92 ± 0.12 km s{sup –1} after correcting for measurement uncertainties and the effect of binaries. This velocity dispersion is consistent with the virial velocity of the region and the diffuse gas velocity dispersion, but significantly larger than the velocity dispersion of the dense, star-forming cores, which have a subvirial velocity dispersion of 0.5 km s{sup –1}. Since the NGC 1333 cluster is dynamically young and deeply embedded, this measurement provides a strong constraint on the initial velocity dispersion of newly formed stars. We propose that the difference in velocity dispersion between stars and dense cores may be due to the influence of a 70 μG magnetic field acting on the dense cores or be the signature of a cluster with initial substructure undergoing global collapse.
Authors:
 [1] ; ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ; ;  [7] ; ; ; ;  [8] ;  [9] ;  [10] ;  [11] ;  [12]
  1. Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06520 (United States)
  2. Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland)
  3. Lowell Observatory, Flagstaff, AZ 86001 (United States)
  4. Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)
  5. Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)
  6. Department of Physics and Astronomy, Vanderbilt University, VU Station B 1807, Nashville, TN 37235 (United States)
  7. Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States)
  8. Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)
  9. Astronomy Department, Wesleyan University, Middletown, CT 06459 (United States)
  10. Spitzer Science Center/Caltech, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
  11. Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States)
  12. Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)
Publication Date:
OSTI Identifier:
22364397
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 799; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; INFRARED SPECTRA; LIMITING VALUES; MAGNETIC FIELDS; MAIN SEQUENCE STARS; PROTOSTARS; STAR CLUSTERS; STAR EVOLUTION; VELOCITY