Monday, January 26, 2009

H II Region

An H II region is a cloud of glowing gas and plasma, sometimes several hundred light-years across, in which star formation is taking place. Young, hot, blue stars which have formed from the gas emit copious amounts of ultraviolet light, ionizing the nebula surrounding them.
H II regions may give birth to thousands of stars over a period of several million years.

H II regions are named for the large amount of ionized atomic hydrogen they contain, referred to as H II by astronomers.