Ionised-Gas Pressure and the Dispersal Time of a Cloud Hosting a Massive Star

This paper addresses a single question: Once a massive star switches on inside a molecular cloud, how large is the ionised volume it can initially sustain, and how quickly does the pressure of that hot gas push the ionisation front across the cloud? 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 for an ionising photon rate of 10^49 per second the initial Stroemgren radius ranges from about a tenth of a parsec in dense gas to about three parsecs in diffuse gas, and subsequent pressure-driven expansion at the ionised sound speed crosses a parsec-scale cloud in roughly one hundred thousand years, short compared with the cloud free-fall and lifetime scales - ionised-gas pressure is therefore a fast dispersal agent once massive stars exist, but it cannot act before they form. The headline values are: Rs compact pc = 0.15; t expand Myr = 0.10; Rs extended pc = 3.15. 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.