See article in The Uinverse Today
Discovered by Abbe Nicholas Louis de Lacaille on September 14, 1751.
NGC 104, better known as 47 Tucanae, is the second largest and second brightest globular cluster in the skies, outshone only by another southern globular, Omega Centauri, NGC 5139. This image is ~ 32′ x 32′.
The stars of 47 Tucanae are spread over a volume nearly 120 light years across. At their distance of 13,400 light years, they still cover an area of the sky of about the same apparent diameter as the full moon, about 30 minutes of arc. Globular cluster 47 Tucanae is approaching us at roughly 19 km/s.
New Chandra observations give the best information yet on why such neutron stars, called millisecond pulsars, are rotating so fast. The key, as in real estate, is location, location, location – in this case the crowded confines of the globular star cluster 47 Tucanae, where stars are less than a tenth of a light year apart. Almost two dozen millisecond pulsars are located there. This large sample is a bonanza for astronomers seeking to test theories for the origin of millisecond pulsars, and increases the chances that they will find a critical transitional object such 47 Tuc W.
47 Tuc W stands out from the crowd because it produces more high-energy X-rays than the others. This anomaly points to a different origin of the X-rays, namely a shock wave due to a collision between matter flowing from a companion star and particles racing away from the pulsar at near the speed of light. Regular variations in the optical and X-ray light corresponding to the 3.2-hour orbital period of the stars support this interpretation.
Registar counts 17,012 stars in this image!