Leo II dwarf galaxy

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Galaxy
Leo II dwarf galaxy
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Leo II
Leo II
AladinLite
Constellation lion
Position
equinox :  J2000.0 , epoch : J2000.0
Right ascension 11 h 13 m 29.2 s
declination 22 ° 09 ′ 17 ″
Appearance
Morphological type dSph, E0 pec  
Brightness  (visual) 12.6 mag
Angular expansion (12.0 × 11.0) ′
Physical data
Affiliation Local group  
Redshift 0.000264  
Radial velocity (79 ± 1) km / s  
distance (690,000 ± 70,000) ly /
(210,000 ± 20,000) pc

history
discovery Robert G. Harrington and Albert George Wilson
Discovery date 1950
Catalog names
PGC  34176 •

The Leo II dwarf galaxy , also known as Leo II (sometimes Leo B ), is a spheroidal dwarf galaxy in the constellation of Leo .

The galaxy , about 690,000 light years away , was discovered in 1950 by Robert G. Harrington and Albert George Wilson of the Mount Wilson Observatory and Palomar Observatory in California .

As of October 2008 , it is one of the 24 known satellite galaxies in the Milky Way .

properties

In the year 2007 the core radius was Leo II to (178 ± 13) pc and determines its tidal radius to (632 ± 32) pc. Also in 2007, a team of 15 scientists observed Leo II through the Subaru telescope , an optical and near-infrared reflecting telescope with an 8.2 m mirror on Mauna Kea in Hawaii . Over two nights of observation , 82,252 stars down to the 26th visual magnitude were counted in 90 minutes of recording time .

The astrophysicists found within Leo II mainly a population of old metal-poor stars, an indication that the galaxy galactic cannibalism survived, during which massive galaxies such as our Milky Way assimilate smaller, to achieve their considerable size.

Observations at the European Southern Observatory estimate the mass of Leo II to be (2.7 ± 0.5) × 10 7 M ⊙ .

additional

Individual evidence

  1. ↑ SIMBAD Astronomical Database . Retrieved November 21, 2011.
  2. ↑ a b c d e NED
  3. ↑ ID Karachentsev, VE Karachentseva, WK Hutch Meier, DI Makarov: A Catalog of Neighboring Galaxies . In: Astronomical Journal . 127, No. 4, 2004, pp. 2031-2068. bibcode : 2004AJ .... 127.2031K . doi : 10.1086 / 382905 .
  4. ↑ Karachentsev, ID; Kashibadze, OG: Masses of the local group and of the M81 group estimated from distortions in the local velocity field . In: Astrophysics . 49, No. 1, 2006, pp. 3-18. bibcode : 2006Ap ..... 49 .... 3K . doi : 10.1007 / s10511-006-0002-6 .
  5. ↑ Tollerud, E., et al. : Hundreds of Milky Way Satellites? Luminosity Bias in the Satellite Luminosity Function . In: Astrophysical Journal . 688, No. 1, November 2008, pp. 277-289. arxiv : 0806.4381 . bibcode : 2008ApJ ... 688..277T . doi : 10.1086 / 592102 .
  6. ↑ Coleman, M., et al. : A Wide-Field View of Leo II: A Structural Analysis Using the Sloan Digital Sky Survey . In: Astronomical Journal . 134, No. 5, November 2007, pp. 1938-1951. arxiv : 0708.1853 . bibcode : 2007AJ .... 134.1938C . doi : 10.1086 / 522229 .
  7. ↑ Leo II: An Old Dwarf Galaxy with Juvenescent Heart . National Astronomical Observatory of Japan. November 28, 2007. Retrieved November 25, 2008.
  8. ↑ Andreas Koch et al. : Stellar Kinematics in the Remote Leo II Dwarf Spheroidal Galaxy — Another Brick in the Wall . In: Astronomical Journal . 134, No. 2, August 2007, pp. 566-578. arxiv : 0704.3437 . bibcode : 2007AJ .... 134..566K . doi : 10.1086 / 519380 .

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