Dense cores in dark clouds. I. CO observations and column densities of high-extinction regions

Journal Article · Sat Jan 15 04:00:00 EST 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160619· OSTI ID:6035290

Meyers, P C; Linke, R A; Benson, P J

Ninety small (approx.5') visually opaque regions have been selected from Palomar Sky Atlas prints and surveyed in the 2.7 mm J = 1..-->..0 lines of C/sup 18/O and /sup 13/CO. The regions are primarily in complexes of obscuration, including those in Taurus and Ophiuchus. The typical C/sup 18/O emission region has C/sup 18/O line width 0.6 km s/sup -1/, optical depth 0.4, excitation temperature 10 K, and column density 2 x 10/sup 15/ cm/sup -2/. It has size 0.3 pc, visual extinction approx.11 mag, and mass approx.30 M/sub sun/. Comparison with equilibrium and collapse models indicates that purely thermal supporting motions are consistent with the present data, but unlikely. If the full C/sup 18/O line width reflects turbulent supporting motions, nearly all of the observed clouds are consistent with stable equilibrium. If only part of the C/sup 18/O line width reflects supporting motions, many clouds are also consistent with turbulent contraction. More than half of the clouds have significant departures from Gaussian line shape. The most common asymmetry is a blueshifted peak in the /sup 13/CO line, which is consistent with contracting motion.

• Research Organization: Department of Physics and AResearch Laboratory of Electronics, Massachusetts Institute of Technology
• OSTI ID: 6035290
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 264:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON 13
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
DATA ANALYSIS
EMISSION SPECTRA
ENERGY-LEVEL TRANSITIONS
EQUILIBRIUM
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FUNCTIONS
ISOTOPES
LIGHT NUCLEI
LINE WIDTHS
NEBULAE
NUCLEI
OPACITY
OPTICAL PROPERTIES
OXIDES
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PHYSICAL PROPERTIES
SPECTRA
SPECTRAL DENSITY
SPECTRAL FUNCTIONS
STABLE ISOTOPES
TURBULENCE