NGC 7789

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Open star cluster
NGC 7789
NGC7789HunterWilson.jpg
Amateur astronomical recording
AladinLite
Constellation Cassiopeia
Position
equinox : J2000.0
Right ascension 23 h 57 m 24 s
declination + 56 ° 42 ′ 30 ″
Appearance

classification II1r
Brightness  (visual) 6.7 likes
Brightness  (B-band) 7.7 likes
Angular expansion 25 '
Number of stars > 15,000
Physical data

Affiliation Milky Way
distance  approx. 7600 ly
(2337 pc )
Metallicity [Fe / H] −0.08
history
Discovered by Caroline Herschel
Discovery time October 30, 1783
Catalog names
 NGC  7789 • C 2354 + 564 • OCl 269 •  Mel  245 •  Cr  460 • Lund 1053 •  GC  5031 •  H  VI 30 •  h  2284 •

NGC 7789 or Herschel's Spiral Cluster is an open star cluster of type II1r in the constellation Cassiopeia in the northern sky . It is about 8,000 light years away from the solar system, has a diameter of about 65 light years and consists of up to 15,000 stars. It has an angular extension of 15 'and an apparent magnitude of 6.7 mag.
Since the stars of the cluster are already well advanced in their evolution , its age is estimated at around 1.5 billion years, far older than most of the others of its kind. The brightest stars are orange giants of type K4 III with an absolute magnitude of −2 , 3 likes. The largest remainder of the other bright stars are giants and subgiants . All stars brighter than +2 mag seem to have evolved out of the main sequence of the HR diagram .

The object was discovered on October 30, 1783 by Caroline Herschel .

Web links

Commons : NGC 7789  - collection of images, videos, and audio files

Individual evidence

  1. ↑ NASA / IPAC EXTRAGALACTIC DATABASE
  2. ↑ a b c SEDS : NGC 7789
  3. ↑ SIMBAD Database
  4. ↑ a b A site Devoted to Stellar Clusters in the Galaxy and the Magellanic Clouds
  5. ↑ Stars and Space November 2007 p. 64
  6. ↑ Deep-Sky Corner _ Cas _ NGC 7789 Herschel's Spiral Cluster.htm
  7. ↑ Seligman
  8. ↑ Stars and Space October 2008 p. 82f