| 47 Tucanae | |
|---|---|
 After Omega Centauri, 47 Tucanae is the brightest globular cluster in the night sky.[1] | |
| Observation data (J2000 epoch) | |
| Class | III[2] |
| Constellation | Tucana |
| Right ascension | 00h 24m 05.67s[3] |
| Declination | −72° 04′ 52.6″[3] |
| Distance | 4.45 ± 0.01 kpc (14,500 ± 32.6 ly)[4][5] |
| Apparent magnitude (V) | +4.09[3] |
| Apparent dimensions (V) | 43.8′ |
| Physical characteristics | |
| Mass | 7.00×105[6] M☉ |
| Radius | 60 ly[7] |
| VHB | 14.2 |
| Metallicity | = −0.78[8] dex |
| Estimated age | 13.06 Gyr[8] |
| Notable features | 2nd brightest globular cluster after Omega Centauri |
| Other designations | ξ Tuc, NGC 104, Caldwell 106, Mel 1,[3] GCl 1, 1RXS J002404.6-720456 |
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47 Tucanae or 47 Tuc (also designated as NGC 104 and Caldwell 106) is a globular cluster located in the constellation Tucana. It is about 4.45 ± 0.01 kpc (15,000 ± 33 ly) from Earth,[9][4] and 120 light years in diameter.[10] 47 Tuc can be seen with the naked eye, with an apparent magnitude of 4.1.[3] It appears about 44 arcminutes across including its far outreaches. Due to its far southern location, 18° from the south celestial pole, it was not catalogued by European astronomers until the 1750s, when the cluster was first identified by Nicolas-Louis de Lacaille from South Africa.
47 Tucanae is the second brightest globular cluster after Omega Centauri, and telescopically reveals about ten thousand stars, many appearing within a small dense central core. The cluster may contain an intermediate-mass black hole.[11][12]
- ^ "Retirement in the suburbs". Retrieved 12 June 2015.
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- ^ a b Cite error: The named reference
mnras404_3_1203was invoked but never defined (see the help page). - ^ McLaughlin, D.E.; et al. (2006). "Hubble Space Telescope Proper Motions and Stellar Dynamics in the Core of the Globular Cluster 47 Tucanae". Astrophysical Journal Supplement Series. 166 (1): 249–297. arXiv:astro-ph/0607597. Bibcode:2006ApJS..166..249M. doi:10.1086/505692. S2CID 116985213.
- ^ "47 Tuc: A Great Globular Cluster of Stars". Astronomy Picture of the Day. August 26, 2008. Retrieved 25 May 2017.
- ^ Kızıltan, Bülent; Baumgardt, Holger; Loeb, Abraham (2017). "An intermediate-mass black hole in the centre of the globular cluster 47 Tucanae". Nature. 542 (7640): 203–205. arXiv:1702.02149. Bibcode:2017Natur.542..203K. doi:10.1038/nature21361. PMID 28179649. S2CID 1289123.
- ^ Freire, Paulo; Ridolfi, Alessandro; Kramer, Michael (2017). "Long-term observations of the pulsars in 47 Tucanae - II. Proper motions, accelerations and jerks". Monthly Notices of the Royal Astronomical Society. 471 (7640): 857–876. arXiv:1706.04908. Bibcode:2017MNRAS.471..857F. doi:10.1093/mnras/stx1533.