 Theory predicts that a young cluster of this size should give birth to stars and substellar objects of all spectral types, from huge, hot O stars down to dim brown dwarfs.However, studies of the Hyades show that it is deficient in stars at both extremes of mass.At an age of 625 million years, the cluster's main sequence turn-off is about , meaning that all heavier stars have evolved into subgiants, giants, or white dwarfs, while less massive stars continue fusing hydrogen on the main sequence.