AAS 201st Meeting, January, 2003
Session 89. Planetary Nebulae and Dusty Clouds
Poster, Wednesday, January 8, 2003, 9:20am-6:30pm, Exhibit Hall AB

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[89.01] Sulfur, Chlorine, and Argon Abundances in Planetary Nebulae III: Observations and Results for a Final Sample

J.B. Milingo (Gettysburg College), K.B. Kwitter (Williams College), R.B.C. Henry (University of Oklahoma)

This poster addresses heavy element ratios based upon new spectro-photometric observations of 20 Galactic Type II PNe with spectral coverage from 3700-9600 Å. A major feature of our observations throughout this study has been the inclusion of the near-infrared lines of [S III] at 9069 and 9532 Å, which allows us to calculate accurate S+2 abundances to either improve upon or confirm results of earlier sulfur abundance studies. For this sample we calculate ratios of S/O, Cl/O, and Ar/O and find average values of S/O=1.1x10-2 ± 1.1x10-2, Cl/O=4.2x10-4 ± 5.3x10-4, and Ar/O=5.7x10-3 ± 4.3x10-3.

We present a comparison of heavy element ratio averages for this sample, a separately observed sample of northern hemisphere PNe, southern hemisphere PNe, and two samples of Galactic Type II PNe taken from the literature. For six objects we are able to compare abundances of S+3 calculated directly from available [S IV] 10.5\mu measurements with those inferred directly from the values of the ionization correction factors for sulfur. The final paper of this study will compile results from a total sample of 86 Galactic PNe, evaluate trends, and use chemical abundance models to interpret results. This research is supported by NSF grant AST-9819123.

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