Omega Centauri

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Globular cluster
ω Centauri
Image taken using VST, image field 51 'x 51'.
Image taken using VST , image field 51 'x 51'.
Constellation centaur
equinoxJ2000.0 , epoch : J2000.0
Right ascension 13 h 26 m 45.9 s
declination −47 ° 28 ′ 37 ″
Concentration class VIII
Brightness  (visual) 5.3 mag
Brightness  (B-band) 6.1 mag
Angular expansion 55 ′
Physical data
Affiliation Milky Way
Redshift (794 ± 17)  ·  10 −6
Radial velocity (+238 ± 5) km / s
distance 17.3  kLj
(5.3  kpc ) 
diameter approx. 150 ly
Age approx. 12 billion years
discovery Edmond Halley
Discovery date 1677
Catalog names
 NGC  5139 • C 1323-472 •  GCl  24 •  ESO  270-SC11 •  Dun  440 •  GC  3531 •

ω Centauri ( Omega Centauri, ω Cen for short , also known as NGC  5139) is a globular cluster in the constellation Centaur . It has an apparent diameter of 55 ′ and an apparent magnitude of 5.3 mag. This makes it the brightest globular cluster in the sky and visible as a small nebula with the naked eye. It also has the greatest absolute brightness , as it is by far the most massive globular star cluster in our Milky Way . Within the Local Group , it is only surpassed in size by Mayall II , a globular cluster of the Andromeda Galaxy. Omega Centauri contains around 10 million stars.

Research history

Although ω Centauri is not a star, it was given a Bayer designation . The object differs from other globular clusters in that it contains several star populations . The latest research carried out with the Hubble Space Telescope and the Gemini Observatory shows that ω Centauri is probably a dwarf galaxy that has since been robbed of its stars by the Milky Way . The peculiarity of this object will now be easier to explain since a black hole with 40,000 solar masses has been found in the center.

Web links

Commons : NGC 5139  - collection of images, videos, and audio files


Individual evidence

  1. ^ NED
  2. a b c d SEDS: NGC 5139
  3. SIMBAD database
  4. a b Astronomers Find Suspected Medium-Size Black Hole in Omega Centauri. April 2, 2008.
  5. a b Article on Spiegel-Online
  6. Seligman
  7. heic0809 - Science Release: Black hole found in enigmatic Omega Centauri. April 2, 2008.