Upper panel: distribution of rotation periods of Argus association (blue squares) and IC 2391 (black circles) members versus B − V color. Confirmed and likely periods are plotted with filled symbols, uncertain periods with open symbols. Data are taken from Messina et al. (2010b). HD 61005 is represented by the (red) star symbol. The dashed and dotted lines represent the upper bounds of the period distribution of Pleiades members (from Barnes 2003).