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. For the most part, the age difference is less than 1 billion years, and is typically below 500 million years. While this isn't incredibly accurate, it suggests that even one measurement of a star's activity should be useful in determining if the star is old or young. The filled circles in the figure show the Sun at different phases of its activity variations.