The Rotation Measurement of 12 Late-Type Binaries

Twelve late-type binaries have been observed with the same instrumental configuration at Kitt Peak National Observatory,USA.The rotational velocities of 15 components in the 12 binaries are determined,including 5 stars whose V sin i are reported for the fist time. with the rotatonal velocities measured by ourselves,we discuss the synchronization in these binary systems.Basically,we find that all components with the orbital period ≤9 days are synchronized.