H II Regions
An H II region is a large insect of gas and changed gas of glowing low density in which star formation has lately taken place. The first H II known region is Orion Nebula discovered in 1610 by Nicolas-Claude Fabri de Peiresc. H II regions, also known as activity nebulae, are glowing clouds of gas and plasma up to several hundred light-years across. H II regions are well known as nebulae where star establishment is taking place. Typically, a Bok globule contains gas of about 10-50 solar masses in an area one light year across. More than one star typically forms within such a globule, which is why stars are often found in clusters.
H II regions are only detected in galaxies, and always in the arms of the curve. They are never determined in elliptical galaxies because these galaxies are thought to have been formed as the result of galactic collisions. During galactic collisions, any preexisting H II parts are likely to be agitated and their density increased to the point where almost all of the gas forms into stars, leaving behind little else.
Looking for anything Else ? Try Our Search
