Extended Nebulae Around WC11 Stars: IRAS 17514-1555

Extract

Imaging and long–slit spectroscopy of the nebula surrounding the WC11 star IRAS 17514–1555 are presented that allow, for the first time, the nebula to be studied without contamination from the underlying WC11 star. These data show that the nebula is photoionized and does not appear to have an obvious scattering component. The nebula consists of two shells: a low density outer region (diameter 18 arcsec) where n_e ∼ 100cm⁻³ and an unresolved inner nebula (diameter < 1.5 arcsec) where n_e > 10⁴cm⁻³. The abundances in the nebula are similar to those found in Type I PN (He and N enriched). Simple models are constructed which demonstrate that the nebula is probably in equilibrium with the central star (T_∗ ∼ 30,000 K). The nebular and stellar properties are compared to those of other late–type WC stars and the evolutionary status of IRAS 17514–1555 discussed.