Boötes I (dwarf galaxy)

Boötes I (dwarf galaxy)

The Boötes Dwarf Galaxy (Boo I dSph) is a galaxy, which appears faint, with a luminosity of 100,000 L and an absolute magnitude of –5.8. It lies about 197 thousand light-years (60.4 kiloparsecs) away in the constellation Boötes. This dwarf spheroidal galaxy appears to be tidally disrupted[1] by the Milky Way Galaxy, which it orbits, and has two stellar tails that cross over to form a cross. Tidally disrupted galaxies usually only form one tail.

Like many of the ultrafaint dwarf spheroidals, the entire galaxy appears fainter than the star Rigel (absolute magnitude –6.8).


  1. ^ Apparent magnitude = Absolute magnitude + Distance modulus = -5.8[1] + 18.9[1] = 13.1


  1. ^ a b c

External links

  • The Universe within 500,000 light-years The Satellite Galaxies (Atlas of the Universe)
  • Two New Galaxies Orbiting the Milky Way (Ken Croswell) April 19, 2006
  • Strange satellite galaxies revealed around Milky Way Kimm Groshong (New Scientist) 17:00 24 April 2006
  • New Milky Way companions found: SDSS-II first to view two dim dwarf galaxies (SDSS) May 8, 2006
  • Astronomers Find Two New Milky Way Companions (SpaceDaily) May 10, 2006
  • Boötes Dwarf Galaxy at Constellation Guide