Plane with coordinates of frequency (in c/d, abscissa) and radial-velocity amplitude (in km s⁻¹, ordinate). The data axis provides the number of frequency–amplitude data pairs resulting from circular orbits fitted to the radial velocities in Table 4, as described in Sect. 3.1. Each spike has a footprint of dimensions 0.008 c/d and 0.1 km s⁻¹; only for better visibility were they enlarged. The floor level is ≤30 ± 6 data points per pixel.