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A survey for dense cores in dark clouds
Benson, P. J.; Myers, P. C.
AA(Wellesley College; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA), AB(Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)
Astrophysical Journal Supplement Series (ISSN 0067-0049), vol. 71, Sept. 1989, p. 89-108. Research supported by the American Astronomical Society, Dudley Observatory, and William and Flora Hewitt Foundation. (ApJS Homepage)
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NASA/STI Keywords:
Dark Matter, Molecular Clouds, Nebulae, Pre-Main Sequence Stars, Star Formation, Ammonia, Infrared Sources (Astronomy)
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A total of 149 dark cloud positions were surveyed for evidence of 'dense cores' in the (J,K) = (1,1) rotating inversion line of NH3. Clouds with strong emission were mapped to determine the position of the core, and maps of 41 cores are presented. The spectrum of the peak emission is fitted by least-squares analysis to determine the optical depth, velocity, intrinsic line width, and excitation temperature. Statistical equilibrium analysis is used to determine the density of the core and the kinetic temperature when possible. Most of the dense cores have temperatures of 10-15 K, densities of 2000-20,000/cu cm, and intrinsic linewidths of 0.2-0.9 km/s. The core masses range from about 0.5 solar in L1517B to 760 solar in L1031B, and their sizes range from 0.06 to 0.9 pc. The cores are not generally spherically shaped, wtih aspect ratios ranging from 1.1 to 4 4. Cores with stars have broader lines than cores without stars.

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