Willman 1

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Willman 1
Observation data (J2000 epoch)
Constellation Ursa Major
Right ascension 10h 49m 22.3s[1]
Declination +51° 03′ 03.6″[1]
Distance 120 ± 20 kly (38 ± 7 kpc)[2]
Type extreme dSph or
unusual globular cluster[1]
Apparent magnitude (V) 15.4 ± 0.4[a]
Other designations
SDSS J1049+5103[1]
See also: Galaxy, List of galaxies

Willman 1 or SDSS J1049+5103[2] is an extreme globular cluster or ultra low-mass dwarf galaxy[3] discovered by a team lead by Beth Willman of New York University, using Sloan Digital Sky Survey data. As of 2006, it is the third dimmest galaxy known, after Boo dSph and UMa dSph, 200 times dimmer than the next dimmest. The galaxy is a satellite of the Milky Way; ~120,000 light-years away. It has an absolute magnitude of -2.5.[2] The luminosity function varies between the center and the tails which suggest mass segregation similar to that found in Palomar 5.[2]

[edit] Notes

  1. ^ 15.4 ± 0.4 apparent magnitude - 5 * (log10(38 ± 7[2] kpc distance) - 1) = -2.5[2] absolute magnitude
  1. ^ a b c d (Willman et al. 2005)
  2. ^ a b c d e f (Willman et al. 2006)
  3. ^ (NED 2007)

[edit] References