Boötes Dwarf Galaxy

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**Boötes Dwarf Galaxy**
Observation data: J2000 epoch

Constellation:	Boötes
Right ascension:	14^h 00^m 06^s^[1]
Declination:	+14° 30′ 00″ ± 15″^[1]
Redshift:
Distance:	197 ± 18 kly (60 ± 6 kpc)^[1]
Type:	dSph^[1]
Apparent dimensions (V):	26′.0 ± 1′.4^[1]
Apparent magnitude (V):	13.1^[a]
Notable features:
Other designations
Boo dSph,^{[citation needed]} Boötes Satellite,^[2] Boötes Dwarf Spheroidal Galaxy,^[2] Boötes dSph galaxy^[2]
See also: Galaxy, List of galaxies

The Boötes Dwarf Galaxy (Boo dSph) is the faintest galaxy yet discovered,^{[citation needed]} as of 2006, with a total luminosity of 100,000 Suns, and an absolute magnitude of -5.8. It lies about 197,000 light-years away in the Bootes constellation. This dwarf spheroidal galaxy appears to be tidally disrupted^[1] by the Milky Way Galaxy which it orbits, and has two stellar trails that cross over to form a cross.^{[citation needed]} Tidally disrupted galaxies usually only form one tail.^{[citation needed]}

The galaxy is fainter than the next known faintest, the Ursa Major dwarf galaxy (absolute magnitude -6.75). It is also fainter than the star Rigel (absolute magnitude -6.8). This discounts dark galaxies such as VIRGOHI21 in the Virgo cluster of galaxies.

[edit] 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

[edit] Notes

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

[edit] References

^ ^a ^b ^c ^d ^e ^f ^g ^h Belokurov, V.; Zucker, D. B.; Evans, N. W.; Wilkinson, M. I.; Irwin, M. J.; Hodgkin, S.; Bramich, D. M.; Irwin, J. M.; Gilmore, G.; Willman, B.; Vidrih, S.; Newberg, H. J.; Wyse, R. F. G.; Fellhauer, M.; Hewett, P. C.; Cole, N.; Bell, E. F.; Beers, T. C.; Rockosi, C. M.; Yanny, B.; Grebel, E. K.; Schneider, D. P.; Lupton, R.; Barentine, J. C.; Brewington, H.; Brinkmann, J.; Harvanek, M.; Kleinman, S. J.; Krzesinski, J.; Long, D.; Nitta, A.; Smith, J. A.; Snedden, S. A. (2006). "A Faint New Milky Way Satellite in Bootes". The Astrophysical Journal 647 (2): L111-L114.
^ ^a ^b ^c SIMBAD Astronomical Database. Results for Bootes dSph. Retrieved on December 20, 2006.