Contour plots showing the confidence with which we can exclude a model with specific parameters for the mass distribution power law (α, from  −1.5 to 1.5, top to bottom), the semimajor axis distribution power law index (β, from  −2.5 to 0.2) and the semimajor axis distribution power law cutoff (a_cutoff, from 10 to 320 AU). The hatched grey area corresponds to the values of a_cutoff within the separation of the known planet HR 8799 b (dashed line). Given the existence of the planet at a separation of  ~68 AU, values of a_cutoff below that separation are de facto excluded. The best fit values of Cumming et al. (2008) for solar-type stars in terms of mass and semimajor axis are α =  −1.31 and β =  −0.61. Bowler et al. (2010a) report a 50% confidence for values of β higher than zero.