By Ron Cowen
Astronomers have discovered a star so speedy that it will eventually leave the Milky Way and venture into the void of intergalactic space.
Using the Multiple Mirror Observatory in Tucson, Ariz., researchers measured the velocity of the star by recording the shift of its light toward longer, redder wavelengths. Traveling the distance between Cleveland and New York City each second, the star is moving twice as fast as the velocity required to escape the Milky Way’s gravity. Warren Brown of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and his colleagues will report their findings on the star, cataloged as SDSS J090745.0+24507, in an upcoming Astrophysical Journal Letters.
The star’s speed and direction—almost straight out from the galaxy’s center—suggest that the star once had a partner, and that the pair passed near the supermassive black hole at the Milky Way’s core. In this scenario, the companion was swallowed by the black hole in a way that propelled the other star toward the abyss, the team proposes.
