2000ApJ...538..226V

Cold, dusty molecular clumps (0.01 pc<diameter<0.50 pc) in the interstellar medium are beginning to reveal their secrets. Using the latest observational findings at sufficiently high angular resolution, an analysis is made of the physical dependencies and energy values inside cold molecular clumps. There are universal physical relations in clumps governing mean parameters such as gas density n, diameter D, magnetic field B, and gas line width σ, with the forms <n≳D^c, <B≳<D>^p, <B≳<n>^k, <σ≳<D>^q. For clumps with diameters <0.5 pc, one finds c=-1.5±0.1, p=-1.5±0.1, k=1.0±0.2.

These exponent values differ from those found by Larson for molecular clouds with sizes greater than 1 pc. These differences in c and k could be indicative of ongoing accretion processes in shocked media as a prelude to star formation. The energy distribution in clumps reveals the following: the support against gravitational collapse in clumps with sizes greater than 0.1 pc comes mainly from turbulent energy, while smaller clumps with sizes less than 0.1 pc are supported by both magnetic and turbulent energies. The clump size of 0.1 pc is critical in many other respects.