The figure to the right shows the age calibration currently used by the HK Project. Activity is on the y axis and age is on the x axis. Clusters with known age and some measured activity are shown with bold letters. The smaller symbols correspond to the age and activity of binaries of known age. Ages in the solar neighborhood Derived ages of dwarf stars in the solar neighborhood.
Lines connect binaries.
The series of filled circles show the Sun at different phases of its activity. The figure at left shows the distribution of age of dwarfs stars near the Sun's mass in the solar neighborhood. Younger stars are at the top. Lines connect stars in binary systems. Since all the stars in the plot could also be varying, the distribution of observed age differences in these binary systems gives us an indication of the precision of our age calibration.