8-13 m spectra of very late type Wolf-Rayet stars

8–13 μm spectra are presented of the late Wolf–Rayet stars, Ve 2-45 (WC9), CRL 2104 (WC8), He 2-113 (WC10) and CPD–56° 8032 (WC10). Both WC10 stars show the unidentified feature at 11.25 μm and one of them that at 8.6 μm; their spectra resemble those of some planetary nebulae. These features are absent in the WC8/9 stars, whose spectra, together with their infrared photometric data, can be understood in terms of ∼ 900 K blackbody spectra subject to some interstellar silicate absorption and with a small excess beyond 10 μm, perhaps due to SiC grains. The WC10 objects are characterized by much lower dust temperatures and their evolutionary status appears to be very different from that of the WC8/9 stars.