Date of Award

1-1-2011

Document Type

Thesis

Degree Name

M.S.

Department

Physics and Astronomy

First Advisor

Toshiya Ueta

Keywords

AGB stars, mass loss

Abstract

We provide high-resolution maps of the circumstellar dust shells of several dozen Asymptotic Giant Branch (AGB) stars using data from the Spitzer space telescope Multiband Imaging Photometer (MIPS) imaged at 70&mu m. AGB stars are the major contributors of chemical elements such as carbon, oxygen and silicon, which are essential to the existence of life in the universe, through mass loss processes that take place at the surface of the star. We probe the spatial distribution of cold (~40 K) dust grains in order to trace the history of mass loss from the observed radial density variation in these shells. Our images illustrate that different morphologies may evolve because AGB stars can already interact with the interstellar medium (ISM) that surrounds them even at these early stages of the AGB mass loss history. Relative motion of the star as well as the ISM with respect to the local environment may be of particular importance for shell structure evolution.

Provenance

Recieved from ProQuest

Rights holder

Kathleen Marie Geise

File size

169 p.

File format

application/pdf

Language

en

Discipline

Astrophysics

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