Typical surface temperatures of asteroids are of the order of 150 K, and therefore, [[*Planck*]{}]{} is observing their thermal emission in the Rayleigh-Jeans regime. For that reason, the number of detectable asteroids increases with observing frequency. For our sample of $5\cdot10^4$ asteroids of the [*Minor Planet Centre*]{}’s catalogue, we find a couple of asteroids at $\nu=30$ GHz, a few tens of asteroids at $\nu=100$ GHz and up to 100 asteroids in the highest frequency band at $\nu=857$ GHz. Approximately 1200 asteroids will have fluxes above half of [[*Planck*]{}’s ]{}single-band detection limit estimated for ideal observation conditions and thus they constitute an abundant population of point sources that possibly hampers the detection of SZ-clusters.

The prediction of comets is very uncertain for the years 2007 through 2009: Many comets are not detected yet, non-active comets are too faint with few exceptions and the coma thermal emission features of active comets is very complex. For these reasons, they have been excluded from the analysis.

Future work concerning [[*Planck*]{}’s ]{}foregrounds {#foreground_omitted}
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Foreground components not considered so far include microwave point sources, such as infra-red galaxies and microwave emitting AGNs. The emission of infra-red galaxies is associated with absorption of star light by 