Omega Centauri
From Wikipedia, the free encyclopedia
A small region at the heart of Omega Centauri, |
|
| Observation data: J2000 epoch | |
|---|---|
| Class: | Globular Cluster |
| Constellation: | Centaurus |
| Right ascension: | 13h 26m 45.89s[1] |
| Declination: | -47° 28′ 36.7″[1] |
| Distance: | 18.3 ± 1.1 kly[2] (5.6 ± 0.3 kpc) |
| Apparent magnitude (V): | 3.7[3] |
| Apparent dimensions (V): | 36′.3 |
| Physical characteristics | |
| Mass: | ( M☉) |
| Radius: | 97 ± 6 ly[4] |
| VHB: | |
| Estimated age: | ~12 Gyr[citation needed] |
| Notable features: | |
| Other designations: | NGC 5139,[1] GCl 24,[1] ω Centauri[2] |
| See also: Globular cluster, List of globular clusters | |
Omega Centauri or NGC 5139 is a globular cluster of stars discovered by Edmond Halley in 1677. It orbits our galaxy, the Milky Way. One of the few that can be seen with the naked eye, it is the largest known globular cluster associated with the Milky Way. Omega Centauri is located about 18,300 light-years (5,600 pc) from Earth and contains several million Population II stars. The stars in its center are so crowded that they are believed to be only 0.1 light years away from each other. It is about 12 billion years old.
Though it is not a star, Omega Centauri was given a Bayer designation. Unlike other globular clusters, it contains several generations of stars. Laura Stanford, a graduate student in the Research School of Astronomy and Astrophysics at Australian National University, speculates that it is the core of a dwarf galaxy several hundred times its present size which was ripped apart and absorbed by our Milky Way galaxy. Theoretical modeling by Dr Glenn van de Ven at Leiden University supports her suspicions.
[edit] See also
[edit] External links
- Hubblesite - Peering into the core of a globular cluster
- Omega Centauri: Former Core of a Dwarf Galaxy?
- Omega Centauri: Proud Cluster or Sad Remnant?
- Omega Centauri at ESA/Hubble
[edit] References
- ^ a b c d SIMBAD Astronomical Database. Results for NGC 5139. Retrieved on 2006-11-16.
- ^ a b van de Ven, G.; van den Bosch, R. C. E.; Verolme, E. K.; de Zeeuw, P. T. (January II 2006). "The dynamical distance and intrinsic structure of the globular cluster ω Centauri". Astronomy and Astrophysics 445 (2): 513-543.
- ^ [1]
- ^ distance × sin( diameter_angle / 2 ) = 97 ± 6 kly. radius
