What (who) is H II region - definition
H II region
![[[Bok globule]]s in H II region [[IC 2944]]](https://commons.wikimedia.org/wiki/Special:FilePath/Bok globules in IC2944.jpg?width=200 "[[Bok globule]]s in H II region [[IC 2944]]")
![Dark star-forming regions within the [[Eagle Nebula]] commonly referred to as the [[Pillars of Creation]]](https://commons.wikimedia.org/wiki/Special:FilePath/Eagle nebula pillars.jpg?width=200 "Dark star-forming regions within the [[Eagle Nebula]] commonly referred to as the [[Pillars of Creation]]")
![Strings of red H II regions delineate the arms of the [[Whirlpool Galaxy]].](https://commons.wikimedia.org/wiki/Special:FilePath/Messier51 sRGB.jpg?width=200 "Strings of red H II regions delineate the arms of the [[Whirlpool Galaxy]].")
![Sagittarius]].](https://commons.wikimedia.org/wiki/Special:FilePath/Messier 17 ESO.jpg?width=200 "Sagittarius]].")
![[[Orion Nebula]]](https://commons.wikimedia.org/wiki/Special:FilePath/Orion Nebula - Hubble 2006 mosaic 18000.jpg?width=200 "[[Orion Nebula]]")
![[[Trifid Nebula]] seen at different [[wavelength]]s](https://commons.wikimedia.org/wiki/Special:FilePath/Ssc2005-02a.jpg?width=200 "[[Trifid Nebula]] seen at different [[wavelength]]s")
![A small portion of the [[Tarantula Nebula]], a giant H II region in the [[Large Magellanic Cloud]]](https://commons.wikimedia.org/wiki/Special:FilePath/Tarantula nebula detail.jpg?width=200 "A small portion of the [[Tarantula Nebula]], a giant H II region in the [[Large Magellanic Cloud]]")
![An optical image (left) reveals clouds of gas and dust in the [[Orion Nebula]]; an infrared image (right) reveals new stars shining within.](https://commons.wikimedia.org/wiki/Special:FilePath/Trapezium cluster optical and infrared comparison.jpg?width=200 "An optical image (left) reveals clouds of gas and dust in the [[Orion Nebula]]; an infrared image (right) reveals new stars shining within.")
LARGE, LOW-DENSITY CLOUD OF PARTIALLY IONIZED GAS
HII regions; HII region; H II Region; H II; HII Region; H II nucleus
An H II region or HII region is a region of interstellar atomic hydrogen that is ionized. Typically the region is in a molecular cloud of partially ionized gas in which star formation has recently taken place, with a size ranging from one to hundreds of light years, and density from a few to about a million particles per cubic cm.
H I region
INTERSTELLAR CLOUD COMPOSED OF NEUTRAL ATOMIC HYDROGEN
H. I. Region; HI region; H I profile; H I; HI Region; Hydrogen cloud
An HI region or H I region (read H one) is a cloud in the interstellar medium composed of neutral atomic hydrogen (HI), in addition to the local abundance of helium and other elements. (H is the chemical symbol for hydrogen, and "I" is the Roman numeral.
Guéra (region)
REGION OF CHAD
Guera Region; Qīrā Region; Guéra Region
Guéra () is one of the 23 regions of Chad, created in 2002 from the former Guéra prefecture. The region's capital is Mongo.
