Astrometric jitter and comparison to solar values. First panel: Astrometric jitter (rms) in the X direction, for ΔT_spot1 (black dots) and ΔT_spot2 (orange dots). The median values are indicated by circles of the same colour (open circles correspond to stars outside the B-V range of our simulations). The green lines correspond to the solar value from Lagrange et al. (2011) at 10 pc (dotted line)and scaled to the distance of each star (solid line). Upward arrows mean that the rms are lower limits (active stars), while downward arrows correspond to upper limits (quiet stars, mostly subgiants). Second panel: Percentage of simulations with rms larger than the solar values of Lagrange et al. (2011) scaled to the distance of each star, for ΔT_spot1 (black) and ΔT_spot2 (orange). Open circles correspond to stars outside the B-V range of our simulations. Third panel: Same as first panel for the Y direction. Fourth panel: Same as second panel for the Y direction.