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

Journal Article · Mon Oct 01 04:00:00 EDT 1979 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/157378· OSTI ID:5631750

Sargent, A I

Molecular clouds of mass approx.10/sup 4/ M/sub sun/ and linear extent approx.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 /sup 12/CO, and observations of /sup 13/CO and 2 mm H/sub 2/CO 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 S155. 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 OB3. The two known stellar birth sites, IC 348 and NGC 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.

• Research Organization: Hale Observatories, California Institute of Technology
• OSTI ID: 5631750
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 233:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COSMIC RADIO SOURCES
ENERGY SPECTRA
H2 REGIONS
MOLECULES
MOTION
NEBULAE
OXIDES
OXYGEN COMPOUNDS
PROPER MOTION
SPECTRA
STAR ACCRETION
STAR CLUSTERS
STAR EVOLUTION