Molecular clouds and star formation. II - Star formation in the Cepheus OB3 and Perseus OB2 molecular clouds

Abstract

view Abstract Citations (168) References (64) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Molecular clouds and star formation. II. Star formation in the Cepheus OB3 and Perseus OB2 molecular clouds. Sargent, A. I. Abstract Molecular clouds of mass 10 M0 and linear extent 60 pc have been detected in the vicinity of the young OB associations Cepheus OB3 and Perseus OB2. These clouds have been mapped in the j = 1 0 transition of 12CO, and observations of 13CO and 2 mm H2CO have been made in selected regions. Three regions which illustrate different stages of star formation have been identified in the Cepheus OB3 cloud. An embedded star may be present in one region. A new subgroup of the association is being created in another. The third is probably the precursor of a star-forming region. All are situated at one edge of the molecular cloud, close to the association stars and the H ii region S1 55. The site of the currently active star-forming region adjacent to the birth sites of the older and younger subgroups of the Cepheus OB3 association suggests that each burst of star formation is produced as a result of the birth of a previous group and thus continues sequentially. Although the way in which star formation is initiated in this association is not established, it is clearly very different from the manner in which it proceeds and may well have resulted from the passage of the galactic density wave. The Perseus OB2 association and molecular cloud are found to deviate considerably from the pattern frequently observed in OB associations and typified by Cepheus 0B3. The two known stellar birth sites, IC 348 and NOC 1333, are spatially very far apart, and no other star-forming regions have been discovered. There is no evidence that the birth of stars in one region triggers star formation in an adjacent area. This may be due to the orientation of the cloud with respect to the local magnetic field. It is clear, however, that no unique mechanism produces OB associations. Subject headings: clusters: associations - interstellar: molecules nebulae: general - stars: formation Publication: The Astrophysical Journal Pub Date: October 1979 DOI: 10.1086/157378 Bibcode: 1979ApJ...233..163S Keywords: Interstellar Gas; Molecular Gases; Nebulae; Protostars; Star Formation; Astronomical Maps; Carbon Monoxide; Clouds; Early Stars; Formaldehyde; Astrophysics; Molecular Clouds:Star Formation; Star Formation:Stellar Associations full text sources ADS | data products SIMBAD (6) Related Materials (1) Part 1: 1977ApJ...218..736S