News Release Archive:

News Release 166 of 1006

May 30, 2012 01:00 PM (EDT)

News Release Number: STScI-2012-25

Stellar Archaeology Traces Milky Way's History


Image: Structure of Milky Way's Halo (Artist's Illustration)

Structure of Milky Way's Halo (Artist's Illustration)STScI-PRC2012-25a

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This illustration shows the Milky Way galaxy's inner and outer halos. A halo is a spherical cloud of stars surrounding a galaxy. Astronomers have proposed that the Milky Way's halo is composed of two populations of stars. The age of the stars in the inner halo, according to measurements by the Paranal Observatory, is 11.5 billion years old. The measurements suggest the inner-halo stars are younger than the outer-halo population, some of which could be 13.5 billion years old.

Object Name: Milky Way

Image Type: Illustration

Credit: NASA, ESA, and A. Feild (STScI)


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