Circumstellar Matter: Neutral Envelopes and Planetary Nebula Formation

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AST 0307277PI HugginsThis is a project studying the matter ejected during the red giant expansion phase of stars as they transition into their final shrunken white dwarf forms, the crucial stage of stellar evolution that terminates the normal lives of all low and intermediate mass stars. The mass ejected by the stars forms an expanding circumstellar envelope of neutral gas and dust that develops into a planetary nebula. Observations are being used to address key aspects of this evolutionary sequence, such as the ways in which stars lose mass toward these end stages of their lives, to help identify the mechanisms governing the mass-loss process, how the complex symmetries of planetary nebulae are imprinted on their neutral circumstellar envelopes by high velocity bipolar jets, and how the neutral envelopes of evolved planetary nebulae fragment into arrays of numerous cometary globules. Basic gas dynamical models are being tested in the course of this work.Broader impacts: The broader impacts of the proposed work have a strong educational focus. They include the direct training of students in research and the synergistic professional development of the principle investigator which includes the mentoring of students, contributing to the training of K-12 science teachers, and the development of new facilities and curricular materials for the teaching of astronomy. This program also fosters international cooperation, and the results will be widely disseminated within and beyond the discipline.