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.

Credit:

NASA, ESA, and G. Meylan (?cole Polytechnique Federale de Lausanne)

About the Image

NASA press release
NASA caption
Id:heic0616b
Type:Observation
Release date:24 October 2006, 16:00
Related release:heic0616
Size:3143 x 2482 px

About the Object

Name:47 Tucanae
Type:• Milky Way : Star : Grouping : Cluster : Globular
Distance:15000 light years

Colours & filters

BandWavelengthTelescope
Optical
B
475 nm Hubble Space Telescope
ACS
Optical
V
555 nm Hubble Space Telescope
ACS
Infrared
I
814 nm Hubble Space Telescope
ACS

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