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Spectroscopy and Interferometry of the Winds of Luminous Blue Variables Georgia State University ScholarWorks @ Georgia State University Physics and Astronomy Dissertations Department of Physics and Astronomy Spring 4-2-2012 Spectroscopy and Interferometry of the Winds of Luminous Blue Variables Noel D. Richardson Center for High Angular Resolution Astronomy Follow this and additional works at: https://scholarworks.gsu.edu/phy_astr_diss Recommended Citation Richardson, Noel D., "Spectroscopy and Interferometry of the Winds of Luminous Blue Variables." Dissertation, Georgia State University, 2012. https://scholarworks.gsu.edu/phy_astr_diss/52 This Dissertation is brought to you for free and open access by the Department of Physics and Astronomy at ScholarWorks @ Georgia State University. It has been accepted for inclusion in Physics and Astronomy Dissertations by an authorized administrator of ScholarWorks @ Georgia State University. For more information, please contact [email protected]. SPECTROSCOPY AND INTERFEROMETRY OF THE WINDS OF LUMINOUS BLUE VARIABLES by NOEL DOUGLAS RICHARDSON Under the Direction of Douglas R. Gies ABSTRACT Massive stars are rare, but emit most of the light we observe in the Universe and create many of the heavy elements in the Universe. In this dissertation, I explore the winds of the massive luminous blue variable (LBV) stars. 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. The mass lost through a hot star’s wind impacts its long-term evolution. 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 or LBVs) 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 and the MIRC beam combiner 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. These results show that all the sample stars exhibit similar types of variability, although with different amplitudes. 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. INDEX WORDS: Circumstellar matter, Stars, Emission-line, Be, Winds, Outflows, Early type, Evolution, Spectroscopic binaries SPECTROSCOPY AND INTERFEROMETRY OF THE WINDS OF LUMINOUS BLUE VARIABLES by NOEL DOUGLAS RICHARDSON A Dissertation Submitted in Partial Fulfillment of Requirements for the Degree of Doctor of Philosophy in the College of Arts and Sciences Georgia State University 2012 Copyright by Noel D. Richardson 2012 SPECTROSCOPY AND INTERFEROMETRY OF THE WINDS OF LUMINOUS BLUE VARIABLES by NOEL DOUGLAS RICHARDSON Committee Chair: Douglas R. Gies Committee: Harold A. McAlister Todd J. Henry Misty C. Bentz Brian D. Thoms Nancy D. Morrison Electronic Version Approved: Office of Graduate Studies College of Arts and Sciences Georgia State University May 2012 iv 0 Dedication This dissertation is dedicated to my family, especially my wonderful wife Kristy and our newest addition, Hailey. Our next chapter is about to begin. v 0 ACKNOWLEDGMENTS This dissertation has taken a large effort to collect and analyze the necessary data. I could not have done this without a large amount of support. First, I would like to thank my wonderfully patient wife, Kristy. She has supported me through the large changes that have occurred over the previous six years, kept me on track when I couldn’t see what to do, and listened to me as graduate school caused stress. She was incredibly understanding as I went on observing runs to the CHARA Array or Lowell Observatory, traveled to conferences, or on collaborative trips. I owe much of this work to her support, and could never thank her enough. Her dedication to the final work in this dissertation is fundamentally important, as she often cared for our daughter so I could write. The rest of my family has also been supportive through this process. My mother encour- aged me through my education, and I wish she were still here so that she would be able to see this final stage. My father has supported me in many ways, and has always listened when I needed to talk. My sisters have been there through it as well, listening to my frustrations and aspirations. During this research, I have gone to Boston twice to work on things with Dan Clemens (BU) and my aunt and uncle in Boston have graciously helped me out at those times by providing a place to stay and transportation while I was there. Doug Gies has been an extraordinary advisor who has allowed me to shape this disser- tation in my own manner from the beginning. He encouraged me to take on projects and did not ever tell me not to pursue work on LBVs, despite his lack of former experience with these stars. He has supported the projects with grants, time, dedication, and enthusiasm. I cannot thank him enough for that. My committee has offered advice related to my career, the dissertation, and helped with acquiring telescope time. In particular, Hal McAlister has encouraged me with CHARA work, even if the PAVO project I undertook did not ever make it far off the ground (due to vi software development issues). Also, Todd Henry encouraged me to apply for SMARTS time, which led to the development of Chapters 4–6 of this dissertation. Nancy Morrison advised me with my undergraduate and M.S. research at the University of Toledo. The methods she taught me provided a solid basis for this research. Her long-term monitoring projects at Ritter Observatory allowed for the development of Chapter 2, which has interesting aspects of LBV physics from an in-depth study of the wind of P Cygni. I appreciate her advice, her time, and her travel for this dissertation. Chapter 2 also benefited greatly by the advice and help of several people. Nevena Markova provided many useful comments, as well as her earlier published data on the star (both spectroscopy and photometry). Erica Hesselbach provided new reduced observations of the star made at Ritter Observatory. John Percy provided additional archival photometry and great advice in the early stages of the project. CHARA observations of P Cygni are shown in Chapter 3. Early CHARA observations of this star developed my interest in LBVs, so special thanks to Peter Tuthill (University of Sydney) and Theo ten Brummelaar for that help. The MIRC observations and analysis presented in Chapter 3 began with the help of Gail Schaefer. Early analysis was performed with her assistance as well as that of John Monnier and Yamina Touhami. Rob Parks performed additional imaging tests at that time. This work continues with help from Fabien Baron. The CHARA Array relies on the additional help of Chris Farrington, P.J. Goldfinger, Sandy Land, Judit Sturmann, Laszlo Sturmann, Nils Turner, and Larry Webster. As previously mentioned, the CTIO 1.5 m telescope operated by the SMARTS Consor- tium was the main facility used for Chapters 4–6 of this thesis. Time was awarded by both the SMARTS Consortium and NOAO. SMARTS time was locally allocated by Todd Henry. The last 1.5 years were allocated by the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy, under contract with the National Science Foundation. Fred Walter managed the queue scheduling of these vii observations, which was certainly difficult with the η Carinae program, and all data were masterfully scheduled. The η Carinae project (Chapter 4) benefited from advice from Mike Corcoran, Kris Davidson, Ted Gull, Roberta Humphreys, Tom Madura, Krister Nielsen, and Julian Pittard. Roberta Humphreys was also a great help in the early stages of my LBV survey. She provided a few targets that I had overlooked and that are certainly interesting in their own respect. Some spectra were obtained at GSU’s Hard Labor Creek Observatory. This facility has come a long way over the time I have spent at GSU. Our department chairman, Dick Miller, has certainly been instrumental in these upgrades and improvements. The new 20 inch telescope was also helped along by Hal McAlister. The installation of this telescope was done with the help of Charles Hopper and Nic Scott, with some additional help from the instrument shop, John Wilson, and many other people in the department. The spectrograph saw first light last summer, which was overseen by many of the people already listed in this paragraph. Additional support for that project came from Ben Jenkins, who completed his M.S. thesis with that instrument. However, I must acknowledge Emily Aldoretta who spent her summer and fall semesters learning the instrument and telescope, the data reduction, and performing some analysis for her undergraduate thesis. Her help was instrumental in showing how much work can be done with that telescope and spectrograph. I am grateful for permission to reproduce figures from other publications. Permissions were granted from Roberta Humphreys, Kerstin Weis, Joseph Cassinelli, Nathan Smith, and Rens Waters. This research has made use of the data archive for the HST Treasury Program on Eta Carinae (GO 9973) which is available online at http://etacar.umn.edu.
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