Astronomy:Ursa Minor Dwarf
| Ursa Minor Dwarf | |
|---|---|
 Ursa Minor Dwarf | |
| Observation data (J2000 epoch) | |
| Constellation | Ursa Minor |
| Right ascension | 15h 09m 08.5s[1] |
| Declination | +67° 13′ 21″[1] |
| Redshift | -247 ± 1 km/s[1] |
| Distance | 200 ± 30 kly (60 ± 10 kpc)[2][3] |
| Apparent magnitude (V) | 11.9[1] |
| Characteristics | |
| Type | E[1] |
| Apparent size (V) | 30′.2 × 19′.1[1] |
| Notable features | Satellite galaxy of Milky Way |
| Other designations | |
| UGC 9749,[1] PGC 54074,[1] DDO 199,[1] UMi Dwarf[1] | |
The Ursa Minor Dwarf is a dwarf spheroidal galaxy, discovered by A.G. Wilson of the Lowell Observatory, in the United States, during the Palomar Sky Survey in 1955.[4] It appears in the Ursa Minor constellation, and is a satellite galaxy of the Milky Way. The galaxy consists mainly of older stars and seems to house little to no ongoing star formation. Its centre is around 225,000 light years distant from Earth.[5]
Evolutionary history
In 1999, Kenneth Mighell and Christopher Burke used the Hubble Space Telescope to confirm that the Ursa Minor dwarf galaxy had a straightforward evolutionary history with a single burst of star formation that lasted around 2 billion years and took place around 14 billion years ago,[6] and that the galaxy was probably as old as the Milky Way itself.[7]
See also
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 "NASA/IPAC Extragalactic Database". Results for Ursa Minor Dwarf. http://nedwww.ipac.caltech.edu/.
- ↑ I. D. Karachentsev; V. E. Karachentseva; W. K. Hutchmeier; D. I. Makarov (2004). "A Catalog of Neighboring Galaxies". Astronomical Journal 127 (4): 2031–2068. doi:10.1086/382905. Bibcode: 2004AJ....127.2031K.
- ↑ 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. doi:10.1007/s10511-006-0002-6. Bibcode: 2006Ap.....49....3K.
- ↑ Bergh, Sidney (2000). The Galaxies of the Local Group. Cambridge, United Kingdom: Cambridge University Press. pp. 257. ISBN 978-1-139-42965-8. https://books.google.com/books?id=H0JMeoqFqEcC&pg=PA257.
- ↑ Grebel, Eva K.; Gallagher, John S., III; Harbeck, Daniel (2003). "The Progenitors of Dwarf Spheroidal Galaxies". The Astronomical Journal 125 (4): 1926–39. doi:10.1086/368363. Bibcode: 2003AJ....125.1926G.
- ↑ van den Bergh, Sidney (April 2000). "Updated Information on the Local Group". The Publications of the Astronomical Society of the Pacific 112 (770): 529–36. doi:10.1086/316548. Bibcode: 2000PASP..112..529V.
- ↑ Mighell, Kenneth J.; Burke, Christopher J. (1999). "WFPC2 Observations of the Ursa Minor Dwarf Spheroidal Galaxy". The Astronomical Journal 118 (366): 366–380. doi:10.1086/300923. Bibcode: 1999AJ....118..366M.
External links
- The Ursa Minor Dwarf on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
| Location | Milky Way → Milky Way subgroup → Local Group → Local Sheet → Virgo Supercluster → Laniakea Supercluster → Observable universe → Universe Each arrow (→) may be read as "within" or "part of". |  | |||||||
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| Satellite galaxies |
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Coordinates: 
15h 09m 08.5s, +67° 13′ 21″
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