47 Tucanae - NGC 104

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 Tucanae is the second brightest globular cluster after Omega Centauri, and telescopically reveals about ten thousand stars, many appearing within a small, very dense central core. The cluster may host an intermediate-mass black hole at its centre.

47 Tucanae contains at least two populations of stars, of different ages or metallicities. The dense core contains a number of exotic stars of scientific interest, including at least 21 blue stragglers - stars that are bluer and more luminous than their mass would normally suggest. Globular clusters efficiently sort stars by mass, with the most massive stars falling towards the center.

Although 47 Tuc appears adjacent to the Small Magellanic Cloud, the latter is some 200,000 light years distant, and thus is over fifteen times farther than 47 Tuc.