NGC 6217

NGC 6217 is a barred spiral galaxy located some 67 million light years away,[3] in the constellation Ursa Minor. It can be located with a 10 cm (4 in) or larger telescope as an 11th magnitude object about 2.5° east-northeast of the star Zeta Ursae Minoris.[4] The galaxy is inclined by an angle of 33° to the line of sight along a position angle of 162°.[3]

NGC 6217
NGC 6217 photographed by the Hubble Space Telescope
Credit: NASA
Observation data (J2000 epoch)
ConstellationUrsa Minor
Right ascension16h 32m 39.217s[1]
Declination+78° 11′ 53.56″[1]
Redshift0.004543 ± 0.000013[2]
Helio radial velocity1,368[3] km/s
Distance67.2 Mly (20.6 Mpc)[3]
Apparent magnitude (V)11.2[4]
Characteristics
Type(R)SB(rs)bc[5]
Apparent size (V)55,000 light years
Other designations
ARP 185, UGC 10470[2][6]

A morphological classification of (R')SB(rs)bc[5] indicates that NGC 6217 has a false outer ring-like structure formed from the spiral arms (R'), a well-defined bar running across the nucleus (SB), a partial inner ring (rs), and moderately-wound spiral arms (bc).[7] The nucleus is spherical in shape, showing no indication of oblateness.[5] The prominent bar spans an angular distance of 48″ (48 arc seconds) across the galaxy along a position angle of 35.97° ± 0.35°. At 10″ southeast of the nucleus is a prominent region of star formation. The inner ring is about 43″.5 across.[8]

NGC 6217 has been characterized as a starburst galaxy, which means it is undergoing a high rate of star formation compared to a typical galaxy. As a result, the spectrum is dominated by stellar photoionization from young, hot stars.[9] This component is less than 10 million years old, producing a blue-hued spectral continuum with absorption weak lines from elements other than hydrogen and helium.[6] At the core of the galaxy is a low-luminosity active galactic nucleus which has formed an H II region.[10]

References
  1. Skrutskie, M. F.; et al. (February 2006), "The Two Micron All Sky Survey (2MASS)", The Astronomical Journal, 131 (2): 1163–1183, Bibcode:2006AJ....131.1163S, doi:10.1086/498708.
  2. "NGC 6216", NASA/IPAC Extragalactic Database, retrieved 2013-06-20.
  3. Gusev, A. S.; et al. (August 2012), "Oxygen and nitrogen abundances of H II regions in six spiral galaxies", Monthly Notices of the Royal Astronomical Society, 424 (3): 1930–1940, arXiv:1205.3910, Bibcode:2012MNRAS.424.1930G, doi:10.1111/j.1365-2966.2012.21322.x, S2CID 118437910.
  4. O'Meara, Stephen James (2007), Steve O'Meara's Herschel 400 Observing Guide, Cambridge University Press, p. 227, ISBN 978-0521858939.
  5. Ann, Hong Bae (December 2003), "CCD Surface Photometry of Spiral Galaxies: Bulge Morphology", Journal of the Korean Astronomical Society, 36 (4): 261–270, Bibcode:2003JKAS...36..261A, doi:10.5303/jkas.2003.36.4.261.
  6. Cid Fernandes, Roberto; González Delgado, Rosa M.; Schmitt, Henrique; Storchi-Bergmann, Thaisa; Martins, Lucimara P.; Pérez, Enrique; Heckman, Timothy; Leitherer, Claus; Schaerer, Daniel (April 2004), "The Stellar Populations of Low-Luminosity Active Galactic Nuclei. I. Ground-based Observations", Astrophysical Journal, 605 (1): 105–126, arXiv:astro-ph/0401416, Bibcode:2004ApJ...605..105C, doi:10.1086/382217.
  7. Buta, Ronald J.; et al. (2007), Atlas of Galaxies, Cambridge University Press, pp. 13–17, ISBN 978-0521820486.
  8. Cabrera-Lavers, A.; Garzón, F. (March 2004), "An Optical Study of a Sample of Spiral Galaxies", The Astronomical Journal, 127 (3): 1386–1404, Bibcode:2004AJ....127.1386C, doi:10.1086/381924.
  9. Elfhag, T.; et al. (February 1996), "A CO survey of galaxies with the SEST and the 20-m Onsala telescope", Astronomy and Astrophysics Supplement, 115: 439–468, Bibcode:1996A&AS..115..439E.
  10. Véron-Cetty, M.-P.; Véron, P. (July 2010), "A catalogue of quasars and active nuclei", Astronomy and Astrophysics (13th ed.), 518: A10, Bibcode:2010A&A...518A..10V, doi:10.1051/0004-6361/201014188.


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