Ursa Minor Dwarf

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Ursa Minor Dwarf
Ursa Minor Dwarf - Giuseppe Donatiello.jpg
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 featuresSatellite galaxy of Milky Way
Other designations
UGC 9749, [1] PGC 54074, [1] DDO 199, [1] UMi Dwarf [1]
Amateur image, 10.7 hr. exposure with Esprit 100 APO Refractor+QHY16200CCD @-20C/ IDAS LP2 filter. Ursa-Minor-Dwarf-Combi-image-text.jpg
Amateur image, 10.7 hr. exposure with Esprit 100 APO Refractor+QHY16200CCD @-20C/ IDAS LP2 filter.

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]

Contents

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

Related Research Articles

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References

  1. 1 2 3 4 5 6 7 8 9 10 "NASA/IPAC Extragalactic Database". Results for Ursa Minor Dwarf. Retrieved 2006-11-29.
  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. S2CID   120973010.
  4. ↑ Bergh, Sidney (2000). The Galaxies of the Local Group. Cambridge, United Kingdom: Cambridge University Press. p. 257. ISBN   978-1-139-42965-8.
  5. ↑ Grebel, Eva K.; Gallagher, John S., III; Harbeck, Daniel (2003). "The Progenitors of Dwarf Spheroidal Galaxies". The Astronomical Journal. 125 (4): 1926–39. arXiv: astro-ph/0301025 . Bibcode:2003AJ....125.1926G. doi:10.1086/368363. S2CID   18496644.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ↑ 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. arXiv: astro-ph/0001040 . Bibcode:2000PASP..112..529V. doi:10.1086/316548. S2CID   1805423.
  7. ↑ Mighell, Kenneth J.; Burke, Christopher J. (1999). "WFPC2 Observations of the Ursa Minor Dwarf Spheroidal Galaxy". The Astronomical Journal. 118 (366): 366–380. arXiv: astro-ph/9903065 . Bibcode:1999AJ....118..366M. doi:10.1086/300923. S2CID   119085245.


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