with the constant $Q'$ model used by various authors. In order to allow a direct and immediate comparison with these studies, we will choose the values of the couple $(\dtp,\dts)$ from the relations $(k_2\dtp=\frac{3}{2 n_{\mathrm{obs}} \qp} ,k_2\dts=\frac{3}{2 n_{\mathrm{obs}} \qs} )$, where $(\qp,\qs)$ are the *constant* normalized quality factors used by @MFJ09. This ensures that the effective tidal dissipation function is the same in both calculations for a given planet with its measured orbital parameters.

In order to use the constant *time lag* model, we must consider many values for $\Delta t$. To constrain this parameter, we follow the analysis of @GS66 and use the Io-Jupiter system to infer an upper limit for $\kp\times\dtp$ in giant extrasolar planets. Since Jupiter is rapidly rotating, with $\omega_{\mathrm{J}}>n$ (hereafter, J indices refer to the value for Jupiter), where $n$ is the orbital mean motion of Jupiter’s satellites, tidal transfer of angular momentum drives the satellites of Jupiter [*outwards*]{}, into expanding orbits. Therefore, the presence of Io in a close orbit provides an upper limit for the time lag in Jupiter. Indeed, if $\dtp$ was too large, the backward evolution of the satellites orbits would imply their disappearance within less time than the age of 