We explore the microwave anisotropies on large angular scales produced by the emission from cold and large dust grains, expected to exist in the outer parts of the Solar system, using a simple toy model for this diffuse emission. Its amplitude is constrained in the far–IR by the COBE data and is compatible with simulations found in the literature. We analyse the templates derived after subtracting our model from the WMAP ILC 7-yr maps and investigate on the cosmological implications of such a possible foreground. The anomalies related to the low quadrupole of the angular power spectrum, the two-point correlation function, the parity and the excess of signal found in the ecliptic plane are significantly alleviated. An impact of this foreground on some cosmological parameters characterizing the spectrum of primordial density perturbations, relevant for on-going and future cosmic microwave background anisotropy experiments, is found.

We acknowledge partial support by the ASI/INAF Agreement I/072/09/0 for the Planck LFI Activity of Phase E2 and the ASI contract I/016/07/0 COFIS. MMacknowledges partial support by FFO Ricerca Libera 2009 and 2010. JMD acknowledges support from the project AYA2010-21766-C03-01.

7 páginas, 6 figuras, 1 tabla.-- El Pdf del artículo es la versión pre-print: arXiv:1010.0830v2

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