User:Bay Flam/note001

From Wikipedia, the free encyclopedia

NGC 104

NGC 104- Image mosaic by E. Kopan (IPAC).

(Field size 19.2´ × 23.3´.)
Observation data (J2000 epoch)
Class III
Constellation Tucana
Right ascension 00h 24m 05.67s[1]
Declination -72° 04′ 52.6″[1]
Distance 13.4 ± ? kly[citation needed] (4.1 ± ? kpc)
Apparent magnitude (V) +4.91[1]
Apparent dimensions (V) 30′.9
Physical characteristics
Mass kg (? M{\odot})
Radius 60 ± ? ly[2]
VHB 14.2
Estimated age ? Gyr
Notable features 2nd brightest globular cluster
after Omega Centauri
Other designations 47B.Tuc, 51G.Tuc, ξ Tuc (Xi Tucanae), BAC 85, L 80, CD -70°12, NGC 104, Mel.1[1], C 106
See also: Globular cluster, List of globular clusters
This box: view • talk • edit


NGC 104 is a globular cluster located in the constellation Tucana. It is about 13,400 light years away from the Sun. It can be seen with the naked eye with a visual magnitude of 4.0, and is the second brightest globular cluster in the sky (after Omega Centauri).

It is also known as 47 Tucanae (or just 47 Tuc), but wrong. it is not Flamsteed designation, becaouse it is not visible under the horizon at Greenwich in England. Correctly it as 47B.Tuc. It is ordered the 47th of Tucana in Bode's star catalogue. Later, Gould listed it ordered the 51st of Tucana in his catalogue, and designated as ξ Tuc (Xi Tucanae).

NGC 104 was discovered by Frederick de Houtman as a star, but he located it the 8th of Hydrus in his star catalogue, its southern location having hidden it from European observers until then. Nicolas Louis de Lacaille noted it as a nebula in 1751. It next cataloged by James Dunlop in 1826, and John Herschel in 1834. The cluster appears roughly the size of the full moon in the sky.

It is noted for having a very bright and dense core. It has 22 known millisecond pulsars, and at least 21 blue stragglers near the core.[3]

NGC 104 is included in Sir Patrick Moore's Caldwell catalogue as C106.

[edit] See also

[edit] References

  1. ^ a b c d SIMBAD Astronomical Database. Results for NGC 104. Retrieved on 2006-11-17.
  2. ^ distance × sin( diameter_angle / 2 ) = 60 ly. radius
  3. ^ "NASA's Hubble Space Telescope Finds "Blue Straggler" Stars in the Core of a Globular Cluster", Hubble News Desk, 1991-07-24. Retrieved on 2006-05-24. 

[edit] External link


Category:Globular clusters
Category:Tucana constellation
Category:NGC objects
Category:Bayer objects