page_title: O-type star
section_title: Giants
hierarchical_section_title: O-type star / Examples / Giants
caption_attribution_description: English&#x3a;&#32; Flame Nebula (no border). "Atlas Image [or Atlas Image mosaic] obtained as part of the Two Micron All Sky Survey (2MASS), a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation." seen here: http://www.ipac.caltech.edu/2mass/gallery/showcase/flameneb/index.html and here: http://antwrp.gsfc.nasa.gov/apod/ap990713.html
context_page_description: An O-type star is a hot, blue-white star of spectral type O in the Yerkes classification system employed by astronomers. They have temperatures in excess of 30,000 kelvin. Stars of this type have strong absorption lines of ionised helium, strong lines of other ionised elements, and hydrogen and neutral helium lines weaker than spectral type B.
  Stars of this type are very rare, but because they are very bright, they can be seen at great distances and four of the 90 brightest stars as seen from Earth are O type. Due to their high mass, O-type stars end their lives rather quickly in violent supernova explosions, resulting in black holes or neutron stars. Most of these stars are young massive main sequence, giant, or supergiant stars, but the central stars of planetary nebulae, old low-mass stars near the end of their lives, also usually have O spectra.
  O-type stars are typically located in regions of active star formation, such as the spiral arms of a spiral galaxy or a pair of galaxies undergoing collision and merger. These stars illuminate any surrounding material and are largely responsible for the distinct coloration of a galaxy's arms.
context_section_description: Iota Orionis
  LH54-425
  Meissa
  Plaskett's star
  Xi Persei
  Mintaka
caption: Alnitak is a triple star system with an O9.7 supergiant and an O9 giant as well as a B0 giant. These stars illuminate the nearby Flame Nebula.
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