NGC 6217

NGC 6217

NGC 6217
NGC 6217 photographed by the Hubble Space Telescope
Observation data
Right ascension 16h 32m 39.217s[1]
Declination +78° 11′ 53.56″[1]
Redshift 0.004543 ± 0.000013[2]
Helio radial velocity 1,368[3] km/s
Distance 67.2 Mly (20.6 Mpc)[3]
Type (R)SB(rs)bc[4]
Apparent dimensions (V) 3′.3 × 3′.3[5]
Apparent magnitude (V) 11.2[5]
Other designations
ARP 185, UGC 10470[2][6]

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.[5] The galaxy is inclined by an angle of 33° to the line of sight along a position angle of 162°.[3]

A morphological classification of (R')SB(rs)bc[4] 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.[4] 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. ^ a b Skrutskie, M. F.; et al. (February 2006), "The Two Micron All Sky Survey (2MASS)", Astrophysical Journal 131 (2): 1163–1183,  
  2. ^ a b "NGC 6217", NASA/IPAC Extragalactic Database, retrieved 2013-06-20. 
  3. ^ a b c d Gusev, A. S.; et al. (August 2012), "Oxygen and nitrogen abundances of H II regions in six spiral galaxies",  
  4. ^ a b c Ann, Hong Bae (December 2003), "CCD Surface Photometry of Spiral Galaxies: Bulge Morphology", Journal of the Korean Astronomical Society 36 (4): 261–270,  
  5. ^ a b c O'Meara, Stephen James (2007), Steve O'Meara's Herschel 400 Observing Guide, Cambridge University Press, p. 227,  
  6. ^ a b 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", The Astronomical Journal 605 (1): 105–126,  
  7. ^ Buta, Ronald J.; et al. (2007), Atlas of Galaxies, Cambridge University Press, pp. 13–17,  
  8. ^ Cabrera-Lavers, A.; Garzón, F. (March 2004), "An Optical Study of a Sample of Spiral Galaxies", The Astronomical Journal 127 (3): 1386–1404,  
  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,  
  10. ^ Véron-Cetty, M.-P.; Véron, P. (July 2010), "A catalogue of quasars and active nuclei", Astronomy and Astrophysics (13th ed.) 518: A10,  

External links

  • "Hubble Opens New Eyes on the Universe", Hubble Site news Center (NASA), September 9, 2009, retrieved 2013-06-18 
  • "NGC 6217 -- Active Galaxy Nucleus", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), retrieved 2013-06-20