Top: convergence of the mean values of inclination (blue curves) and longitude of node multiplied with a sine of inclination (red curves) for Hobson family members in the base model with planetary perturbations alone. The time at abscissa extends to the past, and the ordinate shows difference of the respective variable with respect to the orbit of (18777) Hobson. The reference frame is defined by the invariable plane of the Solar System. Bottom: value of the target function ΔV_Z from Eq. (2) computed from the orbits shown in the top panel. The gray horizontal line indicates 5 m s⁻¹, the estimated escape velocity from the family parent asteroid (Sect. 3). Left panels: 12 members with H ≤ 17.75. Right panels: all Hobson members on multi-opposition orbits. The gray Gaussian curve schematically indicates the solution 365 ± 67 kyr for the age of the Hobson family from Rosaev & Plávalová (2017).