Galactic Radio Astronomy pp 115-128 | Cite as
Expanding Shells of Neutral Hydrogen as Birthplaces of Stellar Associations
Abstract
Expanding shells of neutral hydrogen have been found connected with the associations Per OB2 and Sco OB2. The shells also contain dust and molecules. A model of the spatial configuration and the kinematics of gas, dust and stars is discussed. The stars of the associations lie outside, close to the shells; gas and stars move outward from a common centre of expansion. If the shells are interpreted as old supernova remnants which have been strongly decelerated by the interstellar medium, ages of the order of 1 × 106 yr are obtained. A genetic relationship between stars and shells is suggested. The stars formed in the densest gas shell ; afterwards they separated from the gas, as the shell was further slowed down by intervening interstellar matter. Limits are set on the time scale of star formation. The geometry and the motion of the shell at the moment of star formation account also for the kinematics of Per OB2 and Sco OB2.
Keywords
Star Formation Column Density Supernova Remnant Neutral Hydrogen Interstellar MatterPreview
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