Dissipation quality factor of the Maxwell model as a function of the viscoelastic parameters G and η. Top: for a Jupiter-like two-layer planet tidally perturbed at the Io’s frequency ω ≃ 2.79 × 10^-4   rad   s^-1. Bottom: for a Saturn-like two-layer planet tidally perturbed at the Enceladus’ frequency ω ≃ 2.25 × 10^-4   rad   s^-1. The red dashed line corresponds to the value of (for Jupiter and Saturn, respectively) determined by Lainey et al. (2009–2012). The blue lines corresponds to the lower and upper limits to the reference values taken by the viscoelastic parameters G and η for an unknown mixture of ice and silicates. We assume the values of R_p =  { 10.97,9.14 }  (in units of ), M_p =  { 317.8,95.16 }  (in units of ), and given in Tables 5, 6.