spacetoday.net: Stars found in eccentric orbits around galaxy

Posted: Fri, Jun 12, 2009, 7:45 AM ET (1145 GMT)
Ultracool subdwarf orbits (MIT)

Astronomers announced this week the discovery of a family of stars in unusual eccentric orbits around the galaxy, including one star that may have originated in another galaxy. These stars, called ultracool subdwarfs, are small, low-temperature stars with low concentrations of heavy elements. Astronomers found that these stars occupy unusual orbits compared to other stars in the Milky Way: some are in elliptical orbits that dip into the heart of the galaxy and extend to great distances beyond, while others are in much wider orbits outside the galaxy's disk. One such star, 2MASS 1227-0447, has an orbit that takes it 200,000 light-years beyond the center Milky Way, nearly 10 times as far as the Sun. Astronomers speculate that this star might have been captured from another galaxy that approached too close to the Milky Way and torn apart by the Milky Way's gravity.