against rotation period. The area of the filled circles is proportional to the stellar mass, with the gray circle representing one star that only has a photometric parallax (Lépine & Gaidos 2011) and consequently a poorly determined mass. saturates for P_rot< 10 d, and then decreases as an approximately linear function of log (P_rot). For illustration, the upper x-axis displays the Rossby number (Ro = P_rot/τ_c) for an assumed τ_c = 70 d.