of the submillimetric thermal emission properties of planets, an extension to the Wright & Odenwald model [@1976ApJ...210..250W; @1971AJ.....76..719N] was used. The orbital motion of the planets is sufficiently fast such that their movements including their epicyclic motion relative to the Lagrangian point $L_2$, [[*Planck*]{}’s ]{}observing position, has to be taken into account. All planets are imaged twice in approximate half-year intervals due to [[*Planck*]{}’s ]{}scanning strategy, while showing tiny displacements from the ecliptic plane because of the Lissajous-orbit of [[*Planck*]{}]{} around $L_2$ and their orbital inclinations.

The heat balance equation for a planet or asteroid reads as: $$E + F + W \equiv P_\mathrm{emission} = P_\mathrm{absorption} \equiv I + R\mbox{,}$$ where $E$ denotes the heat loss by thermal emission (i.e. the signal for [[*Planck*]{}]{}), $F$ the heat flux outward from the interior of the planet, $W$ is the heat lost by conduction to the planet’s atmosphere, $I$ is the Solar radiation absorbed and $R$ is the heating of the planet caused by the back-scattering of radiation emanating from the surface of the planet by the atmosphere. The definition of these quantities is given by eqns. (\[eqn\_B\_def\]) through (\[eqn\_R\_def\]):

$$\begin{aligned}
E & = & \epsilon\:\sigma\:T_\mathrm{planet}^4\mbox{,}\label{eqn_B_def}\\
F & = & k\cdot\frac{\upartial T_\mathrm{planet}}{\upartial 