Stellar sorting in globular cluster 47 Tucanae: A seven year study with the NASA/ESA Hubble Space Telescope has provided astronomers with the best observational evidence yet that globular clusters sort out stars according to their mass, governed by a gravitational billiard ball game between stars. Heavier stars slow down and sink to the cluster's core, while lighter stars pick up speed and move across the cluster to its periphery. This process, called "mass segregation", has long been suspected for globular star clusters, but has never before been directly seen in action. [Left] - A photo of the globular star cluster 47 Tucanae taken with the Very Large Telescope, in Chile. It is one of the densest globular clusters in the Southern hemisphere. The cluster contains one million stars. [Right] - An NASA/ESA Hubble Space Telescope colour photo of the core of 47 Tucanae. Multiple photos of this region allowed astronomers to track the "beehive swarm" motion of stars. Precise velocities were obtained for nearly 15,000 stars in this cluster. This image was taken with Hubble's Advanced Camera for Surveys. The international team was made of the following scientists: D.E. McLaughlin (University of Leicester, UK), J. Anderson (Rice University, USA), G. Meylan (?cole Polytechnique Federale de Lausanne, Switzerland), K. Gebhardt (University of Texas at Austin, USA), C. Pryor (Rutgers University, USA), D. Minniti (Pontifica Universidad Catolica, Chile), and S. Phinney (Caltech, USA).

Name: 47 Tucanae
Type: Milky Way : Star : Grouping : Cluster : Globular
Category: Star Clusters
Distance: 15000 light years
Release date: 24 October 2006, 16:00
Credit: [Left]: Very Large Telescope/European Southern Observatory, R. Kotak and H. Boffin (ESO). [Right]: NASA, ESA, and G. Meylan (?cole Polytechnique Federale de Lausanne)

Stellar sorting in globular cluster 47 Tucanae: A seven year study with the NASA/ESA Hubble Space Telescope has provided astronomers with the best observational evidence yet that globular clusters sort out stars according to their mass, governed by a gravitational billiard ball game between stars. Heavier stars slow down and sink to the cluster's core, while lighter stars pick up speed and move across the cluster to its periphery. This process, called "mass segregation", has long been suspected for globular star clusters, but has never before been directly seen in action. This image shows the core of 47 Tucanae. Multiple photos of this region allowed astronomers to track the "beehive swarm" motion of stars. Precise velocities were obtained for nearly 15,000 stars in this cluster. This image was taken with Hubble's Advanced Camera for Surveys.

Name: 47 Tucanae
Type: Milky Way : Star : Grouping : Cluster : Globular
Category: Star Clusters
Constellation: Tucana
Distance: 15000 light years
Release date: 24 October 2006, 16:00
Credit: NASA, ESA, and G. Meylan (École Polytechnique Fédérale de Lausanne)

Globular cluster 47 Tucanae [VLT view]: A photo of the globular star cluster 47 Tucanae taken with the Very Large Telescope, in Chile. It is one of the densest globular clusters in the Southern hemisphere. The cluster contains one million stars.

Name: 47 Tucanae
Type: Milky Way : Star : Grouping : Cluster : Globular
Category: Star Clusters
Constellation: Tucana
Distance: 15000 light years
Release date: 24 October 2006, 16:00
Credit: Very Large Telescope/European Southern Observatory, R. Kotak and H. Boffin (ESO)

Globular cluster 47 Tucanae (ground-based image): This image of 47 Tucanae is a colour composite taken by the Digitized Sky Survey (DSS), the field of view is 2.4x2.8 degrees.

Name: 47 Tucanae
Type: Milky Way : Star : Grouping : Cluster : Globular
Category: Star Clusters
Constellation: Tucana
Distance: 15000 light years
Release date: 24 October 2006, 16:00
Credit: ESA/Hubble (Davide De Martin), the ESA/ESO/NASA Photoshop FITS Liberator & Digitized Sky Survey 2

Globular cluster 47 Tucanae and the Small Magellanic Cloud (ground-based image): This photo was taken by the Japanese astrophotographer Akira Fujii and shows a wide-angle view of the globular cluster 47 Tucanae and the Small Magellanic Cloud.

Name: 47 Tucanae, Small Magellanic Cloud
Type: Milky Way : Star : Grouping : Cluster : GlobularLocal Universe : Galaxy : Size : Dwarf
Category: GalaxiesStar Clusters
Release date: 24 October 2006, 16:00
Credit: Akira Fujii