2017MNRAS.471.3419M

We present an analysis on the potential prevalence of mid-infrared excesses in stars with and without planetary companions. Based on an extended data base of stars detected with the Wide Infrared Survey Explorer (WISE) satellite, we studied two stellar samples: one with 236 planet hosts and another with 986 objects for which planets have been searched, but not found. We determined the presence of an excess over the photosphere by comparing the observed flux ratio at 22 and 12 µm (f₂₂/f₁₂) with the corresponding synthetic value, derived from results of classical model photospheres. We found a detection rate of 0.85 per cent at 22 µm (two excesses) in the sample of stars with planets and 0.1 per cent (1 detection) for the stars without planets. The difference of the detection rate between the two samples is not statistically significant, a result that is independent of the different approaches found in the literature to define an excess in the wavelength range covered by WISE observations. As an additional result, we found that the WISE fluxes required a normalization procedure to make them compatible with synthetic data, probably pointing out a revision of the WISE data calibration.