2009ApJ...707L..27F

We present new far-ultraviolet (far-UV) spectra of an oxygen-rich knot in the Large Magellanic Cloud supernova remnant N132D, obtained with the Hubble Space Telescope (HST)-Cosmic Origins Spectrograph (COS). Moderate-resolution (Δv ~ 200 km/s) spectra in the HST far-UV bandpass (1150 Å ≲ λ ≲ 1750 Å) show emission from several ionization states of oxygen as well as trace amounts of other species. We use the improvements in sensitivity and resolving power offered by COS to separate contributions from different velocity components within the remnant, as well as emission from different species within the oxygen-rich knot itself. This is the first time that compositional and velocity structure in the ultraviolet emission lines from N132D have been resolved. No nitrogen is detected in N132D, and multiple carbon species are found at velocities inconsistent with the main oxygen component. We find helium and silicon to be associated with the oxygen-rich knot and use the reddening-corrected line strengths of O III], O IV], O V, and Si IV to constrain the composition and physical characteristics of this oxygen-rich knot. We find that models with a silicon-to-oxygen abundance ratio of N(Si)/N(O) = 10^–2 can reproduce the observed emission for a shock velocity of ∼130 km/s, implying a mass of ∼50 M_☉ for the N132D progenitor star.