AAS 198th Meeting, June 2001
Session 13. Planetary Nebulae
Display, Monday, June 4, 2001, 9:20am-6:30pm, Exhibit Hall

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[13.01] Testing Nucleosynthesis Theory of S, Cl & Ar Using Planetary Nebulae. I: Abundances in the Northern Sample

K.B. Kwitter (Dept. of Astronomy, Williams College), R.B.C. Henry (Dept. of Physics & Astronomy, U. Oklahoma)

This paper is the first in a series which studies specifically the abundances of sulfur, chlorine, and argon in Type~II planetary nebulae (PNe) in the Galactic disk, extending over a broad range in galactocentric distance. Ratios of S/O, Cl/O, and Ar/O constitute important tests of differential nucleosynthesis of these elements and serve as strict constraints on massive-star yield predictions. We present new ground-based optical spectra extending from 3600-9600{Å} for a sample of 19 northern Type~II PNe. Observation of the strong lines of [S~III] \lambda\lambda9069,9532, allows us to extensively test their effectiveness as S abundance indicators. We also present a new sulfur ionization-correction factor, based on a grid of photoionization models, that includes the effects of matter-boundedness on the relative ionization state distributions. For this northern sample, we find average values of S/O=1.2E-2±0.7E-2, Cl/O=2.8E-4±1.3E-4, and Ar/O=6.3E-3±5.4E-3.

We gratefully acknowledge support from the National Science Foundation through grant AST-9819123.

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