Minimum mass vs. orbital period for the known planets around M-dwarf stars. The red empty dot shows the position of GJ 536 b. Horizontal dashed lines show the mass of the solar system planets for comparison. On the edges of the figure the distribution for each parameter is shown. The cyan shape shows the region where a second planet could exist around GJ 536 (upper limit of the band) and could be detectable given the typical uncertainty of the measurements (lower limit of the band). The green shapes show the habitable region around the star GJ 536. Horizontal lines show the broad scenario, while inclined lines show the narrow one.