Observations of the Dust Around Evolved Stars

Abstract

ISOPHOT has been used to obtain low resolution spectra from 2.5µm to 5µm and 5.8µm to 11.6µm and multi-aperture photometry at 60µm of several evolved stars; oxygen-rich and carbon-rich (including the peculiar carbon-rich stars R CrB and RY Sgr). R CrB was observed early in the ISO mission, 3 weeks after it had been at minimum light. Another spectrum was obtained several months later. The second spectrum shows that the broad plateau (from around 6µm to 8µm) is still present but the flux density has declined from 60Jy to 50Jy. The spectrum for RY Sgr shows the same type of plateau. The multi-aperture data suggest that the dust shells are resolved around R CrB, RY Sgr, Y CVn and RS Lib.