HII regions are volumes of gas surrounding high-mass stars that are ionized and heated by the stellar ultraviolet radiation. This ionization and heating significantly raises the thermal pressure of the gas, which is the principal driver of the dynamics of all but the very smallest and very largest HII regions.
Diffuse Matter from Star Forming Regions to Active Galaxies - A Volume Honouring John Dyson
- Pub Date:
- To be published as a chapter in 'Diffuse Matter from Star Forming Regions to Active Galaxies' - A volume Honouring John Dyson. Eds. T. W. Harquist, J. M. Pittard and S. A. E. G. Falle. 25 pages, 7 figures. Some figures degraded to meet size restriction. Full-resolution version available at http://www.ifront.org/wiki/Dyson_Festschrift_Chapter