NGC 6397

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Globular cluster
NGC 6397
NGC 6397 (ESO) .jpg
Image taken with the Wide Field Imager (WFI) of the ESO 2.2 m telescope at the La Silla Observatory
AladinLite
Constellation altar
Position
equinox :  J2000.0 , epoch : J2000.0
Right ascension 17 h 40 m 41.3 s
declination -53 ° 40 ′ 25 ″
Appearance
Concentration class IX
Brightness  (visual) 5.3 mag
Angular expansion 31 '
Physical data
Integrated spectral type F4
Redshift (+6.30 ± 0.03)  ·  10 −5
Radial velocity (+18.9 ± 0.1) km / s
distance 7.2  kLj
history
discovery Nicolas Lacaille
Discovery date 1751
Catalog names
 NGC  6397 • C 1736-536 •  GCl  74 •  ESO  181-SC004 • Bennett 98, Caldwell 86, h 3692, GC 4311

NGC 6397 is a globular cluster in the constellation Altar, 7,200 light years away . NGC  6397 has a diameter of 31  arc minutes and an apparent magnitude of 5.3 mag.

NGC 6397 is the second closest globular cluster after M4 and only a little further away than this. In contrast to M4, however, it is not obscured by an interstellar cloud , so the single stars in NGC 6397 are the easiest to observe. It is therefore very often used together with M4 for scientific studies. In one of these investigations, an elliptical galaxy about 1 billion light-years away was found by chance between the stars of NGC 6397, which in turn is surrounded by a swarm of around 200 globular clusters. This is the most distant known collection of globular clusters.

The property was built in 1751 by Nicolas Louis de Lacaille .

  • Central area as seen with the Hubble Space Telescope

  • Detail with single stars. The width of the image corresponds to about 1.5 minutes of arc, this corresponds to about 4 light years.

Individual evidence

  1. ↑ NASA / IPAC EXTRAGALACTIC DATABASE
  2. ↑ Harlow Shapley, Helen B. Sawyer: A Classification of Globular Clusters . In: Harvard College Observatory Bulletin . tape 849 , 1927, pp. 11-14 , bibcode : 1927BHarO.849 ... 11S .
  3. ↑ a b SEDS : NGC 6397
  4. ↑ Seligman

Web links

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