摘要：Snowden & Young suggested that the reason why there are GK subgiants is because they are members of binaries, which would bring them above the main sequence in an Hertzsprung–Russell (HR) diagram. They studied a sample of 30 G0-K1 IV stars and were disappointed to find only two to be spectroscopic binaries. With more accurate radial velocities I found seven binaries in their samples of subgiants and control stars; orbital elements are given for those seven. Using Hipparcos parallaxes and SIMBAD data, I found that nearly all of the G0-K1 IV stars fall on the evolutionary tracks by Garardi et al. for Population I stars with masses of 0.9–1.9 M e and ages of up to 10 10 yr, which are normal parameters for nearby field stars. Therefore there is no problem regarding the existence of GK subgiants.
