tokens: are thought to be representative for larger areas of the comet, locally there may be large deviations from the global value as detected at CG’s final landing site. Figure 18. Diurnal temperature variation for example facet in TM's FOV at 3 au. Thermal inertia: Γ = 67 Jm −2 K −1 s −1/2 . Due to an instrument failure to penetrate the subsurface layers, the depth- and temperature-dependency of the local layering remain unknown. Therefore, in this first refinement study, facet thermal inertia is assumed to be constant. The results for simulation durations of 10 d (without optimized starting conditions) are compared to those of 50 d (with and without optimized starting conditions), one orbit and three orbits. It can clearly be seen that a few comet rotations of simulation time are not sufficient to obtain a converged solution. Increasing the simulation time improves the results, especially when optimized starting conditions are used. Most facets in the TM's FOV require simulation times above 50 up to 200 d, when using appropriate initial conditions. Above a couple of 100 d, the starting conditions begin to lose importance unless the initial guess is rather far off. The limiting factor for a final in-depth TM data analysis lies in the still prevailing uncertainties for the detailed local landing environment and the final lander orientation. The preliminary shape model used in this example does not reflect the correct illumination duration on the lander itself. The model facets in the TM’s FOV are cumulatively illuminated for about the measured amount of time if not the correct time spans, pointing to the wrong lander or individual facet orientation for the preliminary DTM used. 5 CONCLUSIONS Highly resolved celestial body shapes are computationally very demanding when performing a thorough thermophysical investigation. This is especially true for highly non-convex shapes by itself or in combination with disc-integrated data. Also highly resolved local landing sites on nearly convex shapes such as expected to be obtained for Ryugu will benefit from a model that can take into account a local DTM with large detail. A method is presented for efficiently calculating converged surface temperatures and temperature-dependent quantities. While the equations applied solve for subsurface temperatures as well, the method is only applicable to surface temperatures. The software itself can be used to calculate depth profiles as well, losing the method’s advantage, however, of a reduction in computation time. The only speed-enhancing measure in that case is the implemented parallelization. The method presented adds several pre-processing steps to the actual thermophysical modelling. Some calculation steps, however, are fast – the iterative evaluation of the upper boundary condition to obtain starting conditions takes seconds to minutes depending on the size of the shape model. The calculation of illumination conditions is not fast, but is already required as input
ner_tags: O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject O O O O O O O O O O O O B-Instrument O O O O O O B-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula I-Formula O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Instrument O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Instrument O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Instrument O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Model O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-CelestialObject O O O O O O O O O O O O B-Model O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O