NOAO >   Observing Info >   Approved Programs >   2012B-0405

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Proposal Information for 2012B-0405


PI: Ting-Hui Lee, Western Kentucky University, ting-hui.lee@wku.edu
Address: Physics Department, 1906 College Heights Blvd, Bowling Green, KY 42101, USA

CoI: Richard A. Shaw, National Optical Astronomy Observatory
CoI: Letizia Stanghellini, National Optical Astronomy Observatory

Title: Chemical Abundances of Compact Planetary Nebulae in the Galactic Disk

Abstract: We propose to observe 20-30 compact planetary nebulae (PNe) in the Galactic disk using the SOAR Goodman spectrograph to derive their chemical abundances. We seek moderate-resolution spectra (R ~ 1500) of these young PNe from (lambda)=3700 Ato 7400 \AA, as they are the best objects for studying the impact of metallicity and dust on PN morphology. This is a pilot program to assess the feasibility of eventually obtaining optical spectra for 150 compact PNe using SOAR and other telescopes to build a complete database of chemical abundances for compact PNe in the Galactic disk. Our analysis will incorporate IR collisional excitation lines from \it Spitzer, which will give more reliable abundances for some ions. Our scientific goals include constraining stellar evolution models, quantifying the contribution of low- to intermediate-mass stars to chemical enrichment, and investigating the apparent under-abundant sulfur anomaly in PNe. We will compare these abundances to those in a similar study of ours on Magellanic Cloud PNe to assess chemical enrichment in a low-metallicity environment. We request 2 nights for this pilot project.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2012B-0405

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