Top panel: synthetic radial velocity dataset (black points) superimposed with the circular orbit model (red line) used to generate the data. This model shows only a linear drift during the timespan of the observations. Bottom panel: the 99.7% confidence region of the posterior distribution for the orbital period versus the radial velocity semi-amplitude (black line). The modelled orbit is marked with the red circle. The upper limit in the radial velocity amplitude (at 10 km s^-1) comes from the prior.