Virial Parameters of Giant Molecular Clouds: Bound, Marginal and Dispersing Populations from Published Line Widths

This paper addresses a single question: Are the giant molecular clouds catalogued by millimetre surveys gravitationally bound as whole objects, or do their line widths imply that most of their mass is only marginally held and will disperse? Using published molecular-cloud and young-stellar-object measurements as inputs, and carrying the spin-torsion density bound of 9.72 x 10^57 kilograms per cubic metre and its critical shear of 8.56 x 10^32 per second as fixed comparison scales, the calculation finds that the virial parameter computed from published masses, radii and line widths spans values below unity for compact massive complexes to above two for diffuse clouds, with a typical giant molecular cloud near the marginal value; the population is therefore mixed rather than uniformly bound, and cloud lifetimes of a few free-fall times follow naturally. The headline values are: alpha range = 0.70 to 3.49; alpha typical = 0.70; tff typical Myr = 2.70. All values are computed from the stated formulae and inputs; this is a simulated and computed study, not a measurement. Where the comparison scales supplied by the torsion framework turn out to be too remote to influence the process, that outcome is reported as a negative result rather than passed over.