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Leo II
Observation data (J2000 epoch)
Constellation	Leo
Right ascension	11 13 29.2
Declination	+22° 09′ 17″
Redshift	0.000264 (79 ± 1 km/s)
Distance	690 ± 70 kly (210 ± 20 kpc)
Apparent magnitude (V)	12.6
Characteristics
Type	E0 pec
Apparent size (V)	12.0 x 11.0 arcmin
Other designations
PGC 34176, DDO 93

Leo II (or Leo B) is a dwarf spheroidal galaxy about 690,000 light-years away in the constellation Leo. It is one of 24 known satellite galaxies of the Milky Way. Leo II is thought to have a core radius of 178 ± 13 pc and a tidal radius of 632 ± 32 pc. It was discovered in 1950 by Robert George Harrington and Albert George Wilson, from the Mount Wilson and Palomar Observatories in California.

Recent Findings

In 2007 a team of 15 scientists observed Leo II through the 8.2 meter Subaru optical-infrared telescope in Mauna Kea, Hawaii. Over 2 nights, 90 minutes of exposures were taken and 82,252 stars were detected down to a visible magnitude of 26. They found that Leo II consists largely of metal-poor older stars, a sign that it has survived the galactic cannibalism under which massive galaxies (e.g., the Milky Way) consume smaller galaxies to attain their extensive size.

Observation at ESO estimates Leo II's mass to be (2.7 ± 0.5)×10 M_⊙.

See also

• Dwarf galaxy
• Local Group, a description of the group of galaxies that includes the Milky Way.

References

1. ^ "NASA/IPAC Extragalactic Database". Results for Leo B. Retrieved 2006-11-18.
2. I. D. Karachentsev; V. E. Karachentseva; W. K. Hutchmeier; D. I. Makarov (2004). "A Catalog of Neighboring Galaxies". Astronomical Journal. 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi:10.1086/382905.
3. Karachentsev, I. D.; Kashibadze, O. G. (2006). "Masses of the local group and of the M81 group estimated from distortions in the local velocity field". Astrophysics. 49 (1): 3–18. Bibcode:2006Ap.....49....3K. doi:10.1007/s10511-006-0002-6.arXiv:0708.1853
4. Tollerud, E.; et al. (Nov 2008). "Hundreds of Milky Way Satellites? Luminosity Bias in the Satellite Luminosity Function". Astrophysical Journal. 688 (1): 277–289. arXiv:0806.4381. Bibcode:2008ApJ...688..277T. doi:10.1086/592102.
5. Coleman, M.; et al. (Nov 2007). "A Wide-Field View of Leo II: A Structural Analysis Using the Sloan Digital Sky Survey". Astronomical Journal. 134 (5): 1938–1951. arXiv:0708.1853. Bibcode:2007AJ....134.1938C. doi:10.1086/522229.
6. "Leo II: An Old Dwarf Galaxy with Juvenescent Heart". National Astronomical Observatory of Japan. 28 Nov 2007. Retrieved 25 Nov 2008.
7. Andreas Koch; et al. (August 2007). "Stellar Kinematics in the Remote Leo II Dwarf Spheroidal Galaxy—Another Brick in the Wall". Astronomical Journal. 134 (2): 566–578. arXiv:0704.3437. Bibcode:2007AJ....134..566K. doi:10.1086/519380.

• Harrington R. G.; Wilson A. G. (1950). "Two New Stellar Systems in Leo". Publications of the Astronomical Society of the Pacific. 62 (365): 118–120. Bibcode:1950PASP...62..118H. doi:10.1086/126249.

External links

• Media related to Leo II (dwarf galaxy) at Wikimedia Commons

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