H II region Reference Libraries

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Stephans Quintet
2010-09-13 16:27:55

Stephan's Quintet in the constellation Pegasus is a visual grouping of five galaxies which four form the first compact galaxy group ever discovered. The group was discovered by Édouard Stephan in 1877 at Marseilles Observatory and is the most studied of all the compact galaxy groups. NGC 7320, which has extensive H II regions, is the brightest member of the visual grouping and is where...

H II Region
2004-10-19 04:45:41

H II Region -- An H II region is an emission nebula associated with hot, young, blue stars, and star forming regions. H II, or singly-ionized hydrogen, is nebular gas ionized by ultraviolet light emitted by these hot, young stars of spectral type O and B. The sizes of H II regions are determined both by the amount of gas present, and by the luminosity of the O and B stars -- the more...

Triangulum Galaxy
2004-10-19 04:45:40

Triangulum Galaxy -- The Triangulum Galaxy, Messier object M33, is a spiral galaxy of type Sc located in the constellation Triangulum. Triangulum is small relative to its larger neighbors such as the Milky Way and Andromeda Galaxy, but is about average compared to most spiral galaxies in the universe. Triangulum is a member of the Local Group of galaxies and may be a gravitationally...

Word of the Day
  • Withering but not falling off, as a blossom that persists on a twig after flowering.
The word 'marcescent' comes from a Latin word meaning 'to wither'.