Hobson family represented by two possible plane projections of the proper orbital elements: (i) semimajor axis a_P vs. sine of the inclination sinI_P in the top panel, and (ii) semimajor axis a_P vs. eccentricity e_P in the bottom panel. The largest fragments (18777) Hobson (red) and (57738) 2001 UZ160 (blue) are shown by diamonds, and smaller family members are shown by filled circles (gray are the five single-opposition orbits). Vertical and horizontal bars are formal uncertainty values of the respective proper element from Table A.1. The uncertainty in e_P is large due to perturbing effect of the g + g₅ − 2g₆ secular resonance. The gray dashed ellipses indicate proper element zones in which fragments may land if they are ejected isotropically from the barycenter of the family with 4 m s⁻¹ velocity (assuming the true anomaly f = 50° and the argument of perihelion such that ω + f = 0°). The tilt in the bottom panel may be due to the perturbing effect of the g + g₅ − 2g₆ resonance, however. The particular dispersion of the family members in e_P at a_P ≃ 2.5636 au, with the noticeable uncertainty of the a_P values, is due to the perturbation by the 9J-8S-2 three-body mean-motion resonance.