The rotation periods of the BSSs and blue lurkers (BLs) vs. T_eff. BSSs and BLs with known rotation periods are plotted with green circles and yellow diamonds, respectively. BSSs with a measured ﹩v\sin i﹩ have a maximum rotation period and are plotted with downward blue triangles. BSSs with ﹩v\sin i﹩ < 10 km s⁻¹ have a known lower limit on their maximum rotation period and are plotted with upward red triangles. Using MIST evolutionary tracks, we mapped the T_eff of main-sequence stars that are halfway through their main-sequence lifetimes to their radii at that time. We can then calculate the rotation periods of these stars for a given equatorial velocity (i.e., ﹩v\sin i﹩ at an inclination of 90°); we show these velocities as dashed lines. The radius of a star grows throughout its main-sequence lifetime, so these lines will shift lower for a star that is closer to the ZAMS and higher for a star closer to the TAMS.