47 Tucanae
globular cluster in the constellation Tucana
Key facts
- Class
- III
- Constellation
- Tucana
- Right ascension
- 00 24 05.539
- Declination
- −72 ° 04 ′ 53.20 ″
- Distance
- 4.45 ± 0.01 kpc (14,500 ± 32.6 ly )
- Apparent magnitude v
- +4.09
- Apparent dimensions v
- 43.8 ′
- Mass
- 7.00 × 10 M ☉
- Radius
- 60 ly
- Metallicity
- [ Fe/H ] = −0.78 dex
- Estimated age
- 13.06 Gyr
- Notable features
- 2nd brightest globular cluster after Omega Centauri
- Other designations
Article
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 (14,500 ± 32.6 ly) from Earth, and 120 light years in diameter. 47 Tuc can be seen with the naked eye, with an apparent magnitude of 4.1. 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.