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W.P. Blair, R. Sankrit, P. Ghavamian (JHU/CAS), J.C. Raymond (SAO), J.A. Morse (ASU)
The Puppis A supernova remnant (SNR) is unique among galactic SNRs in showing optical, high-velocity O-rich ejecta knots in conjunction with a much larger shell due to a circumstellar/interstellar interaction. At a distance of 2 kpc, the full extent of Puppis A (55 arcmin) corresponds to 32 pc, and the kinematic age (based on the fast-moving O-rich material) corresponds to 3700 years. Previous optical and UV observations of the shell show the extinction to be moderately high but patchy. A bright shocked cloud on the eastern limb of the SNR was detected with the Hopkins Ultraviolet Telescope in 1995, but very little ultraviolet work has been done on Puppis A.
We have used the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite to make the first successful FUV observation of the O-rich material in Puppis A. We observed two separate emission knots within the ejecta, including the so-called `omega' filament, obtaining kinematically resolved line profiles for C~III \lambda977 and O~VI \lambda\lambda1032,1038. C~III is the strongest line observed at both positions and the line profile is very significantly impacted by self-absorption (implying even stronger intrinsic emission than observed). The O~VI doublet lines are weaker but clearly detected at both positions, appearing in a peculiar ratio of 1032/1038 < 1 (the optically thick ratio of the doublet). The lines at both positions are broadened well above the ~100 km/s resolution of FUSE with the LWRS aperture, with the omega filament showing full widths near 400 km/s and the second knot showing 300 km/s. Material at these velocities could easily account for the observed O~VI emission lines. Although a detailed models are needed, the presence of strong C~III emission in the shocked ejecta point clearly to carbon in the O-rich ejecta. Comparison to stellar evolution models thus seem to point toward an intermediate (~15-20 solar mass) precursor for this SNR.
This research is supported by NASA grant NAS-532985 to the Johns Hopkins University.
The author(s) of this abstract have provided an email address for comments about the abstract: wpb@pha.jhu.edu
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.