A search for H II regions embedded in intermediate-mass molecular clouds

Abstract

view Abstract Citations (1) References (28) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Search for H II Regions Embedded in Intermediate-Mass Molecular Clouds Moriarty-Schieven, G. H. ; Hughes, V. A. ; MacLeod, G. C. Abstract The results of a radio-continuum survey of embedded H II regions of a number of relatively nearby molecular clouds of moderate size are reported. A number of flat-spectral-index sources were found, for which flux densities were measured at 1.3, 2.8, and 9 cm. The relationship of these sources with their associated molecular clouds is discussed. It is concluded that (1) the star-forming efficiency of these clouds is 2-3 percent, and possibly as high as 5 percent; (2) early-type stars can form in molecular clouds with mass more than 10,000 solar; (3) studies that predict the most massive star that can form in a molecular cloud of a given mass may be underestimating the mass of the cloud because of selection effects; and (4) an energy-balance criterion for collapse of a molecular clouds, similar to the Jeans criterion but using the turbulence kinetic energy of the cloud rather than the thermal energy, may predict where massive stars form. Publication: The Astronomical Journal Pub Date: January 1989 DOI: 10.1086/114966 Bibcode: 1989AJ.....97..172M Keywords: B Stars; H Ii Regions; Molecular Clouds; Sky Surveys (Astronomy); Star Formation; Stellar Mass; Continuous Spectra; Main Sequence Stars; Radio Sources (Astronomy); Raster Scanning; Astrophysics; NEBULAE: H II REGIONS; STARS: FORMATION full text sources ADS | data products SIMBAD (10)