47 Tucanae

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Globular cluster
47 Tucanae
Recorded with the VISTA
Recorded with the VISTA
AladinLite
Constellation Toucan
Position
equinox :  J2000.0 , epoch : J2000.0
Right ascension 00 h 24 m 05.67 s
declination -72 ° 04 ′ 52.6 ″
Appearance
Concentration class III
Brightness  (visual) 4.91 mag
Brightness  (B-band) 5.78 likes
Angular expansion 30.9 ′
Color excess
E (BV) (redness) 		0.037 mag
Physical data
Affiliation Milky Way
Integrated spectral type G4
Redshift −0.000062 ± 0.000001
Radial velocity (−18.7 ± 0.2) km / s
distance about 17100  Lj
(about 5000  pc ) 
diameter 120 ly
Age 10 billion years
history
discovery Nicolas Louis de Lacaille
Discovery date 1751
Catalog names
 NGC  104 • C 0021-723 •  GCl  1 •  ESO  50-SC9 •  Mel  1 •  Dun  18 •  GC  52 • 47 Tucanae • ξ Tucanae • Lac 1 • h 2322

47 Tucanae (also known as NGC 104 ) is the second brightest globular cluster in the sky after Omega Centauri and can be seen as a small nebula with the naked eye. It's a particularly large, old cluster and about 15,000 light-years from Earth.

Discovery and naming

The name 47 Tucanae comes from the fact that the star cluster was initially regarded as a star due to its compact appearance and great apparent brightness and was named accordingly. Further investigated has it first in 1751 the French astronomer Nicolas Louis de Lacaille .

Location and characteristics

High-resolution image of the globular cluster center created using the Hubble space telescope

Seen from Earth, 47 Tucanae appears to be right next to the Small Magellanic Cloud , which, however, is many times further away. It is only visible from the southern hemisphere. With an apparent diameter of 30 ′ , it has a brightness of 4.9 mag. Within a diameter of approx. 120 light years, the star cluster houses several million stars, including several red giants . In the center of the cluster, the stars are very densely packed and some are less than 0.1 light-years apart.

Long-term observations with the Fermi Gamma-ray Space Telescope reveal 47 Tucanae as a weak source of gamma radiation, which is presumably generated by millisecond pulsars .

Web links

Commons : 47 Tucanae  - Collection of Images, Videos and Audio Files

Individual evidence

  1. ↑ a b c SIMBAD query
  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 Students for the Exploration and Development of Space
  4. ↑ NASA / IPAC Extragalactic Database
  5. ↑ http://iopscience.iop.org/0004-637X/533/1/215/pdf/0004-637X_533_1_215.pdf
  6. ↑ http://www.eso.org/public/germany/news/eso1302/
  7. ↑ 47 Tuc - a large globular cluster - Astronomy Picture of the Day from August 26, 2008.
  8. ↑ X-Ray Stars of 47 Tuc - Astronomy Picture of the Day of July 21, 2005 (English).
  9. ↑ Fermi's Gamma-Ray Sky - Astronomy Picture of the Day of March 21, 2009.