Debiased J- (left) and Z-band (right) linear polarization degree as a function of projected rotational velocity. Our data are plotted as black dots and data from the literature (see text) as open diamonds (the arrow stands for an upper limit on v sin i). Positive detection of linear polarization (P/σ ≥ 3) is indicated by open circles surrounding the black dots. Some objects are labeled. For LP 415−20AB we plotted the average v sin i since both components share similar values; for the LP 349−25 binary system both components are plotted separately given their differing spectroscopic rotational velocities. Velocity measurements and their associated error bars are taken from the literature as explained in the text and Table 1.