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We present new thermal IR photometry and spectral energy distributions (SEDs)of eight classical Cepheids (type I) and three type II Cepheids, using VISIRthermal IR photometric measurements, supplemented with literature data. We usedthe BURST mode of the instrument to get diffraction-limited images at 8.59,11.25 and 11.85 {\mu}m. The SEDs show a IR excess at wavelengths longer than10{\mu}m in ten of the eleven stars. We tentatively attribute these excesses tocircumstellar emission created by mass loss from the Cepheids. With somehypotheses for the dust composition, we estimated a total mass of the enveloperanging from 10-10 to 10-8 M\odot. We also detect a spatially extended emissionaround AX Cir, X Sgr, W Sgr, Y Oph and U Car while we do not resolve thecircumstellar envelope (CSE) for the other stars. The averaged circumstellarenvelope brightnesses relative to the stellar photosphere are {\alpha}(AX Cir)= 13.8\pm2.5%, {\alpha}(X Sgr) = 7.9\pm1.4%, {\alpha}(W Sgr) = 3.8\pm0.6%,{\alpha}(Y Oph) = 15.1\pm1.4% and {\alpha}(U Car) = 16.3\pm1.4% at 8.59 {\mu}m.With this study, we extend the number of classical Cepheids with detected CSEsfrom 9 to 14, confirming that at least a large fraction of all Cepheids areexperiencing significant mass loss. The presence of these CSEs may also impactthe future use of Cepheids as standard candles at near and thermal infraredwavelengths.

Thermal infrared properties of classical and type II Cepheids Diffraction limited 10 microns imaging with VLT/VISIR