A Nearby Hypervelocity Star
In 1988, Jack Hills predicted the existence of a star whose velocity was greater than the escape velocity of the galaxy. Such a star, a hypervelocity star (HVS), was first discovered in 2005. Since then, about 20 hypervelocity stars have been found. Recently, another HVS was found using the LAMOST survey. This is the closest HVS that we currently know.
This HVS, known as J091206.52+091621.8, or LAMOST-HVS1, is the first hypervelocity star to be discovered with the LAMOST survey. The star has an apparent magnitude of 13, which is brighter than Pluto. LAMOST-HVS1 is an early B-type star with a strong helium presence. Comparing to our Sun, LAMOST-HVS1 is larger, brighter, and hotter.
LAMOST-HVS1 is found in the same area as the other known HVSs. The data gathered on the star suggests that it originated near the galactic center. With further measurements, the exact origin of LAMOST-HVS1 can be identified.
Image: An artist’s impression of a hypervelocity star (Credit: Ben Bromley, University of Utah)