H II Regions

H II regions are areas of space filled with hydrogen gas that have been ionized by the ultraviolet light from young, hot stars. These stars are typically very massive and emit large amounts of energy, which strips electrons from hydrogen atoms, creating a region of positively charged ions and free electrons. This process gives H II regions their distinctive glow, often seen in colors like red due to the emission of light from hydrogen. H II regions are important for studying star formation and the lifecycle of matter in galaxies, as they signify where new stars are actively forming.