CfA OIR Division Lunch Talks

October 21, 1999 Pratt Conference Room, Perkin G-04, 12:30 pm

Optical and Infrared Astronomy Division Talk


The Characteristics of Binaries
in the Halo and Disk Populations of the Galaxy

Dr. David Latham, CfA

One way to study the formation and early history of the Galaxy is to look at the kinematics and chemistry of old stars that just happen to be passing through the solar neighborhood. The stars with the highest velocities and weakest metallicities belong to the halo of the Galaxy. For many years it was the standard wisdom that binaries are very rare in the halo. Our survey of a large sample of stars selected for high proper motions has shown that the old ideas are wrong, and that the spectroscopic binaries in the halo have characteristics similar to the disk populations, with a few intriguing differences that can be understood as the result of stellar evolution.