Sextans A

Sextans A
Sextans dwarf.jpg
Irregular galaxy Sextans A. The bright Milky Way foreground stars appear yellowish in this view. Beyond them lie the stars of Sextans A with young blue star clusters clearly visible.
Observation data (J2000 epoch)
Constellation Sextans
Right ascension 10h 11m 00.8s[1]
Declination -04° 41′ 34″[1]
Redshift 324 ± 2 km/s[1]
Distance 4.31 ± 0.13 Mly (1.32 ± 0.04 Mpc)[2][3][4]
Type IBm[1]
Apparent dimensions (V) 5′.9 × 4′.9[1]
Apparent magnitude (V) 11.9[1]
Notable features Square in shape
Other designations
UGCA 205,[1] DDO 75,[1] PGC 29653[1]
See also: Galaxy, List of galaxies

Sextans A ( as known as UGCA 205 ), is a tiny dwarf irregular galaxy. It spans about 5000 light-years across, and is located within the Local Group of galaxies, which includes our Milky Way galaxy. At 4.3 million light-years away from Earth, Sextans A is one of most distant members of the Local Group, and is notable for its peculiar square shape. Massive short-lived stars exploded in supernovae that caused more star formation, triggering yet more supernovae, ultimately resulting in an expanding shell. Young blue stars now highlight areas and shell edges high in current star formation, which from the perspective of observers on Earth appears roughly square.[5]

References

  1. ^ a b c d e f g h i "NASA/IPAC Extragalactic Database". Results for Sextans A. http://nedwww.ipac.caltech.edu/. Retrieved 2006-11-18. 
  2. ^ Dolphin, Andrew E. et al. (March 2003). "Deep Hubble Space Telescope Imaging of Sextans A. II. Cepheids and Distance". The Astronomical Journal 125 (3): 1261–1290. arXiv:astro-ph/0211486. Bibcode 2003AJ....125.1261D. doi:10.1086/346279. http://www.iop.org/EJ/article/1538-3881/125/3/1261/202477.html. 
  3. ^ I. D. Karachentsev, V. E. Karachentseva, W. K. Hutchmeier, D. I. Makarov (2004). "A Catalog of Neighboring Galaxies" (abstract). Astronomical Journal 127 (4): 2031–2068. Bibcode 2004AJ....127.2031K. doi:10.1086/382905. 
  4. ^ 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. 
  5. ^ http://apod.nasa.gov/apod/ap981103.html



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Look at other dictionaries:

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  • Sextans B — Pas d’image Données d’observation (Époque J2000.0) Constellation Sextant Ascension droite (α) 10h 00m Déclinaison (δ) +05° 20′ …   Wikipédia en Français

  • Sextans A — Datos de observación (Época J2000.0) Tipo IBm …   Wikipedia Español

  • Sextans A — Données d’observation (Époque J2000.0) Constellation Sextant Ascension droite (α) 10h …   Wikipédia en Français

  • Sextans — bezeichnet: Sextans (Münze), römische Münze Sextant (Sternbild), lateinischer Name für das Sternbild Diese Seite ist eine Begriffsklärung zur Unterscheidung mehrerer mit demselben Wort bezeichneter Begriffe …   Deutsch Wikipedia

  • Sextans — Sex tans, n. [L. See {Sextant}.] 1. (Rom. Antiq.) A Roman coin, the sixth part of an as. [1913 Webster] 2. (Astron.) A constellation on the equator south of Leo; the Sextant. [1913 Webster] …   The Collaborative International Dictionary of English

  • Sextans — (Sextantarius, lat.), 1) ein Sechstheil eines Ganzen, s. As 1); 2) Kupfermünze = 1/6 As, gewöhnlich mit zwei Punkten bezeichnet (d.i. 2 Unzen); 3) 2/6 Pfund od. 2 Unzen; 4) ein Gefäß, welches 2 Cyathi hielt …   Pierer's Universal-Lexikon

  • Sextans — (lat.), röm. Kupfermünze, = 1/6 As …   Meyers Großes Konversations-Lexikon

  • SEXTANS — sexta pars assis: De qua voce sic Gronovius, Trientem et Sextantem volunt esse Siculorum τρίαντα et ἕξαντα; in quo tamen difficultatem inveniunt, quum significatio prorsus alia sit; nam ἕξας semis, τρίας quadrans. Nec repi???si quis sequi malit.… …   Hofmann J. Lexicon universale

  • Sextans — [seks′tənz] n. an equatorial constellation between Leo and Hydra …   English World dictionary

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