RUI: Proto-Planetary Nebulae - High-Resolution Studies with Enlarged Sample

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The goal of this program is to better understand proto-planetary nebulae, objects in transition as evolved stars from the asymptotic giant branch to the planetary nebula phase, by determining their physical properties. These objects represent an important but poorly understood phase in the evolutionary cycle of stars. The project is enlarging the sample of confirmed proto-planetary nebulae, to carry out high-resolution spectral and spatial observations of them, especially using molecular hydrogen emission, to investigate their properties. The results of a unique, decade-long NSF-supported study of pulsational variability in these objects, a study being continued and extended, are being analyzed and prepared for publication. The program here involves the following: (1) an analysis of an enlarged sample of proto-planetary nebulae candidates chosen with different properties from most of those studied thus far; (2) high-resolution spectroscopy of molecules to study the chemistry and dynamics of the circumstellar envelopes; (3) high-resolution infrared imaging of proto-planetary nebulae to study the dust directly from its thermal emission; (4) a high- resolution chemical abundance study of the central stars to investigate the effects of nucleosynthesis on the asymptotic giant branch; and (5) analysis and continuation of the unique light variability study of proto-planetary nebulae being carried out at Valparaiso University. A significant amount of the observational data is already in hand. Additional data will be acquired with telescopes and instruments at the national astronomical observatories.Broader Impacts: This activity has a very positive impact on the training of science students, the education of liberal arts students, and on the infrastructure for science at Valparaiso University. Three students each year serve as research assistants on the project. They are trained in the use of modern astronomical equipment, taught to carry out the observations and reduce the data, and learn how to analyze the data and prepare the results for dissemination. They experience almost all phases of a research program and present their results at conferences. Women and minorities are actively sought as participants, and the project director has a strong record of having women students participate in his research. The excitement of this research project is integrated into the general education astronomy classes and some of the real data used in laboratory research experience. The research infrastructure at Valparaiso University, an undergraduate institution, is enhanced by the continued vitality of the astronomy program that this project provides. The program provides a more modern CCD detector and new computers for data