Milky Way Leftover Shell Stars Discovered In Galactic Halo

This illustration shows the disk of our Milky Way galaxy, surrounded by a faint, extended halo of old stars. Astronomers using the Hubble Space Telescope to observe the nearby Andromeda galaxy serendipitously identified a dozen foreground stars in the Milky Way halo. They measured the first sideways motions (represented by the arrows) for such distant halo stars. The motions indicate the possible presence of a shell in the halo, which may have formed from the accretion of a dwarf galaxy. This observation supports the view that the Milky Way has undergone continuing growth and evolution over its lifetime by consuming smaller galaxies.
Illustration Credit: NASA, ESA, and A. Feild (STScI)

2013-02-21 14:31:55

Source: http://www.universetoday.com/100158/milky-way-leftover-shell-stars-discovered-in-galactic-halo/