The Age Range of Hyades Stars

Abstract

On the basis of canonical models, the age of Hyades supercluster stars, whether in the Hyades and Praesepe clusters or the noncluster field, ranges from (5-6) x 10^8 to 10^9 yr. The difference between the parallax derived from the supercluster motion and that obtained from Hipparcos observations has a dispersion only twice that of the mean dispersion of the individual Hipparcos values. The supercluster appears not to contain red giants on the first ascent of the red giant branch, but only asymptotic giant branch (``clump'') stars. The masses obtained for individual components of binary stars in the supercluster show a dispersion of less than 10% when compared with model predictions.