Date of Award

Spring 4-2-2012

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

First Advisor

Douglas R. Gies

Second Advisor

Harold A. McAlister

Third Advisor

Todd J. Henry

Fourth Advisor

Misty C. Bentz

Fifth Advisor

Brian D. Thoms

Sixth Advisor

Nancy D. Morrison

Abstract

Massive stars are rare, but emit most of the light we observe in the Universe and create many of the heavy elements. New observational approaches and long time-series are utilized in order to examine the basic observable properties of the stars and the mass lost during their lifetimes. In order to study the winds and the long-term changes of the stars, hot stars with some of the strongest winds (the luminous blue variables) were studied in detail with optical spectroscopy and photometry. A 25-year survey on the prototype P Cygni is presented, where the long-term changes are documented for many parameters that have not been examined before. In addition, we present a detailed study of the H-band emitting region through interferometric imaging with the CHARA Array as well as spectrophotometry. A detailed study of the Hα line variability of the LBV η Carinae near its recent periastron is presented. The LBV candidate HDE 326823 is found to be a binary system with variability driven by the close binary companion and Roche lobe overflow. Finally, I present a three-year study of many LBVs in the Milky Way Galaxy and Magellanic Clouds for a statistically significant survey of the long-term variability properties of these rare stars as a population. Future studies of LBV winds are outlined, as well as a short discussion of Georgia State University’s Hard Labor Creek Observatory for these types of studies.

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