The star formation process in molecular clouds associated with Herbig Be/Ae stars. II - The nonhomologous collapse of the CrA cloud

Abstract

view Abstract Citations (72) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The star formation process in molecular clouds associated with Herbig Be/Ae stars. II. The nonhomologous collapse of the CrA cloud. Loren, R. B. Abstract Millimeter-wavelength molecular line observations of CO, (C-13)O, C(O-18), H2CO, HCN, HCO(+), CS, and SO toward a dust cloud in CrA that contains several young Herbig Be/Ae stars are analyzed. The internal and external heating sources are identified on the basis of the CO corrected-antenna-temperature distribution and compared with the column-density distribution as determined by additional (C-13)O corrected-antenna-temperature mapping. The hybrid ratio of (C-13)O to C(O-18) corrected antenna temperature is examined as a function of both velocity and spatial variation across the cloud core. Differences in the distributions of the other molecules are discussed, CO line-broadening observations are presented, and the data are used to determine the velocity-radial distance law. It is concluded that star formation in the CrA cloud has resulted from self-gravitational collapse guided primarily by the cloud's magnetic field, that slow gravitational contraction has maintained the cloud's ellipticity up to the highest densities observed, and that the velocity field follows from a nonhomologous collapse with velocity varying as the -0.5 + or - 0.2 power of radial distance. Publication: The Astrophysical Journal Pub Date: February 1979 DOI: 10.1086/156793 Bibcode: 1979ApJ...227..832L Keywords: A Stars; Abundance; B Stars; Molecular Excitation; Nebulae; Star Formation; Carbon Monoxide; Density Measurement; Gravitational Collapse; Line Spectra; Millimeter Waves; Velocity Distribution; Astrophysics; Carbon Monoxide:Interstellar Clouds; Collapse:Interstellar Clouds; Interstellar Clouds:Star Formation full text sources ADS | data products SIMBAD (4)