47 Tucanae (NGC 104)
Distance: 15,650 Light Years

Right Ascension: 00 : 24.1 (hours : minutes)
Declination: -72 : 05 (degrees : minutes)

The concentrated light of one million stars packed into a volume of space 120 light years across makes 47 Tucanae the second brightest globular cluster in the sky, surpassed only by Omega Centauri. If earth were placed near the center of 47 Tucanae the collective starlight would create a nighttime as bright as day. Although it is the classic metal rich cluster, its metal abundance is still only 25% that of our sun. Metal abundance appears to have implications regarding a stars suitability to form planets. A concerted effort was made by the Hubble Space Telescope to search for planets within 47 Tucanae but failed to find any. The lack of planets in this compact star system supports the belief that metal poor stars in general are not conducive to planet formation. Recent work though has astronomers reconsidering this conclusion as there may still be a strong possibility of gas-giant planets located much further out from stars in globular clusters.

The crowded core of 47 Tucanae is a virtual laboratory of exotic objects such as millisecond pulsars (neutron stars rotating from 100 to 1000 times per second), compact binary systems and possibly even stellar mass black holes. 47 Tucanae has the highest number of known radio pulsars of any cluster. Strong evidence exists for stellar collisions within the tight confines of the compact core. A subset of enigmatic blue stars known as "Blue Stragglers", first described by Alan Sandage in 1953, have been identified in the overcrowded cluster core of 47 Tucanae. These mysterious stars received their name because they appear to be "straggling" away from the evolutionary path of normal stars. They are twice as massive and one fifth the age as typical stars in the cluster. Their age, mass and location in the densest regions of the cluster center suggests that they formed from collisions and mergers of lower mass stars.