SIMBAD references

We have gathered from the literature near and mid infrared (photometric and spectroscopic) data for Galactic planetary nebulae, with special attention to planetary nebulae surrounding Wolf-Rayet type central stars ([WR]PN). These data have been analyzed to obtain insight into the dust-properties of [WR]PN and their evolutionary status. We have found that a sizeable fraction of [WR]PN seems to contain hot dust (1000-2000K), probably located in the winds of the central stars. The mean dust temperature is shown to decrease with decreasing [WC] spectral type. This is in line with suggestions that the [WC] sequence is an evolutionary sequence from late to early types. [WR]PN in different diagrams, when compared to those of non-[WR]PN, suggest that [WR]PN form a homogeneous class of planetary nebulae. There is an unusually large proportion of [WR]PN showing PAH features in their spectra.