Mass-mass diagram of 47 Tuc ai. The plot on the left shows M_c as a function of cos i, while i is the inclination of the system. The plot on the right shows M_c as a function of M_p. The grey region in the left plot is excluded, as it implies negative M_p. For the plot on the right, the grey region is excluded by the mass function and the constraint that sin i ≤ 1. The red lines in both the plots show nominal values and the total mass derived from $\dot{\omega }=0.1601\pm 0.0046$ deg yr⁻¹ (see Sect. 3.5). From these, we inferred that M_tot = 2.41 ± 0.11 M_⊙, M_c, min ≥ 0.7 M_⊙, and M_p, max ≤ 1.7 M_⊙.