Leo II (dwarf galaxy)
{{Short description| Dwarf Spheroidal galaxy in the constellation Leo }}
{{Infobox Galaxy
| name = Leo II
| image = LG Leo II (26422781005).jpg
| epoch = J2000
| type = E0 pec {{cite web
| title=NASA/IPAC Extragalactic Database
| work=Results for Leo B
| url=http://nedwww.ipac.caltech.edu/
| accessdate=2006-11-18 }}
| dist_ly = 690 ± 70 kly (210 ± 20 kpc)
{{cite journal
|author1=I. D. Karachentsev |author2=V. E. Karachentseva |author3=W. K. Hutchmeier |author4=D. I. Makarov | title=A Catalog of Neighboring Galaxies
| journal=Astronomical Journal
| date=2004
| volume=127
| issue=4
| pages=2031–2068
| bibcode=2004AJ....127.2031K
| doi=10.1086/382905| doi-access=free
}}
{{cite journal
| author=Karachentsev, I. D.
| author2=Kashibadze, O. G.
| title=Masses of the local group and of the M81 group estimated from distortions in the local velocity field
| journal=Astrophysics
| date=2006
| volume=49
| issue=1
| pages=3–18
| bibcode=2006Ap.....49....3K
| doi=10.1007/s10511-006-0002-6 | s2cid=120973010
}}[https://arxiv.org/abs/0708.1853 arXiv:0708.1853]
| z = 0.000264 (79 ± 1 km/s)
| constellation name = Leo
}}
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.
{{cite journal
| author = Tollerud, E.
| display-authors = etal
| title = Hundreds of Milky Way Satellites? Luminosity Bias in the Satellite Luminosity Function
| journal = Astrophysical Journal
| date = Nov 2008
| volume = 688
| issue = 1
| pages = 277–289
| doi = 10.1086/592102
| bibcode=2008ApJ...688..277T
| arxiv=0806.4381
| s2cid = 15468628
}}
Leo II is thought to have a core radius of 178 ± 13 pc and a tidal radius of 632 ± 32 pc.
{{cite journal
| author = Coleman, M.
| display-authors = etal
| title = A Wide-Field View of Leo II: A Structural Analysis Using the Sloan Digital Sky Survey
| journal = Astronomical Journal
| date = Nov 2007
| volume = 134
| issue = 5
| pages = 1938–1951
| bibcode = 2007AJ....134.1938C
| doi = 10.1086/522229
|arxiv = 0708.1853 | s2cid = 14819170
}}
It was discovered in 1950 by Robert George Harrington and Albert George Wilson, from the Mount Wilson and Palomar Observatories in California.
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.
{{cite web
| url = http://subarutelescope.org/Pressrelease/2007/11/28/index.html
| title = Leo II: An Old Dwarf Galaxy with Juvenescent Heart
| accessdate = 25 Nov 2008
| publisher = National Astronomical Observatory of Japan
| date = 28 Nov 2007
}}
Observation at ESO estimates Leo II's mass to be (2.7 ± 0.5)×107 M⊙.
{{cite journal
| author = Andreas Koch
| display-authors = etal
| title = Stellar Kinematics in the Remote Leo II Dwarf Spheroidal Galaxy—Another Brick in the Wall
| journal = Astronomical Journal
| date = August 2007
| volume = 134
| issue = 2
| pages = 566–578
| url = http://www.iop.org/EJ/abstract/1538-3881/134/2/566
| doi = 10.1086/519380
| bibcode=2007AJ....134..566K
|arxiv = 0704.3437 | s2cid = 15079314
}}
See also
- Dwarf galaxy
- Local Group, a description of the group of galaxies that includes the Milky Way.
References
{{reflist}}
- {{cite journal | author = Harrington R. G. | author2 = Wilson A. G. | date = 1950 | title = Two New Stellar Systems in Leo | journal = Publications of the Astronomical Society of the Pacific | volume = 62 | issue = 365| pages = 118–120 |doi=10.1086/126249 | bibcode=1950PASP...62..118H | doi-access = free }}
External links
- {{commons category-inline}}
{{Milky Way}}
{{Sky|11|13|29.2|+|22|09|17|690000}}
Category:Dwarf elliptical galaxies
{{Elliptical-galaxy-stub}}