Figure 17.

Properties of the surface distribution of the magnetic field (derived from Zeeman–Doppler Imaging) of the M dwarfs observed with the spectropolarimeters ESPaDOnS (Canada–France–Hawaii Telescope) and NARVAL (Télescope Bernard Lyot) as a function of rotation period and mass. Larger symbols indicate stronger fields, symbol shapes depict the degree of axisymmetry of the reconstructed magnetic field (from decagons for purely axisymmetric to sharp stars for purely non-axisymmetric), and colours the field configuration (from blue for purely toroidal to red for purely poloidal). Solid curves represent contours of constant Rossby number Ro=0.1 (saturation threshold) and 0.01. The theoretical full-convection limit (0.35 M_⊙) is plotted as a horizontal dashed line, and the approximate limits of the three stellar groups discussed in the text are represented as horizontal solid lines. Compiled from the studies by Morin et al. [192,195,196], Donati et al. [197] and Phan-Bao et al. [198].