Molecular clouds associated with young open star clusters

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5383657

Leisawitz, D T

Regions around 69 open star clusters were searched for spectral line emission from the J = 1 ..-->.. 0 rotational transition of /sup 12/CO. Of these, 47 regions were completely or nearly completely mapped with a sampling interval of 7.5 arcminutes. The region surveyed around each cluster was at least 10 cluster diameters in size, typically approx.3 square degrees. Survey sensitivity is sufficient to detect lines as weak as 1 K over a range in velocity +/- 83 km s/sup -1/. Clusters in this sample have well-determined distances ranging from approx.1 to 5 kpc and ages approximately less than or equal to 100 million years. The physical characteristics and the kinematics of the ensemble of molecular clouds associated with the clusters are examined. This enables empirical determination of the systematic interaction between young star clusters and the interstellar matter from which they form. Molecular clouds associated with clusters whose ages are less than 5 million years are expanding away from those clusters at approximately 10 km s/sup -1/, thus explaining the relative paucity of emission detected in the neighborhoods of older clusters. Molecular clouds associated with clusters older than approx.5 Myr are smaller, less massive, and colder than clouds associated with extremely young clusters. Evidence is found that the clouds, to some extent, dissolve in the stellar radiation field.

• Research Organization: Texas Univ., Austin (USA)
• OSTI ID: 5383657
• 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
CLOUDS
EQUATIONS
KINETIC EQUATIONS
MOLECULES
PHYSICAL PROPERTIES
STAR CLUSTERS
STELLAR ACTIVITY
STELLAR WINDS