INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedtbrougb, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely. event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. U·M·I University Microfilms International A Bell & Howell Information Company 300 North Zeeb Road. Ann Arbor. M148106-1346 USA 313/761-4700 800/521-0600 Order Number 9416060 Stellar oxygen abundances King, Jeremy R., Ph.D. University of Hawaii, 1993 U·M·I 300 N. Zeeb Rd. Ann Arbor,MI48106 STELLAR OXYGEN ABUNDANCES A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAII IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN ASTRONOMY DECEMBER 1993 By Jeremy R. King Dissertation Committee: Ann M. Boesgaard, Chairperson James N. Heasley Barry J. Labonte Alan N. Stockton Lawrence J. Wallen © Copyright 1993 by Jeremy R. King III Acknowledgements An undertaking such as this is not possible without the help and support of many people. First and foremost of these was my advisor Dr. Ann Boesgaard. Much of what I have learned about stellar spectroscopy over the past five years was from her. The responsibilities she assigned me and the trust she placed in me during this time were valued and her patient and friendly manner were much appreciated. When I originally approached Ann about doing an observational thesis on oxygen, she responded enthusiastically and included expanded support for this work in her proposal to NSF; I am grateful to her for giving me such freedom in the choice of a thesis topic. Additionally, Ann gratefully provided me with brief respites from my research by allowing me to look after her house, which has such a lovely and peaceful ocean view. I also much enjoyed tending to Daiquiri, her "astronomical cat", whose persitent and best efforts could not permanently keep me on an early rising schedule. Many thanks and much aloha, Ann, for your encouragement, genuine interest, and the opportunity to work with you. Dr. James Heasley is the person most responsible for me coming (and, ironically, almost not coming) to Hawai'i. He has given me much guidance while Ann Boesgaard was a visiting scientist at CFHT and Eberly chair at Penn State. Although it is not completely clear to me, I have probably benefited from the many times he has grumbled at me, my thesis, and my TeX skills. The idea to observe oxygen in open clusters was one he pushed strongly for and originally suggested. Many thanks to Dr. Barry Labonte for his humor, his valued input, and his broad knowledge of stellar astronomy. It was Barry's idea to use the 400 mm camera on the FOS to perform most of the stellar oxygen observations when I was seemingly out of options. Barry also accompanied me to Mees Solar Observatory and carried out the lion's share of the solar observations there. Dr. Alan Stockton made the stellar observations a reality by designing and directing the construction of the camera mount and the appropriate slit. He also contributed financially to that effort and I am very grateful to him. Dr. Larry Wallen graciously accepted the task of being the outside member on my committee. For the past two years, I have also been fortunate enough tc work with Dr. Constantine Deliyan­ nis. I appreciate his enthusiastic interest ill my thesis work and his constant encouragement. He has given me useful feedback and detailed comments on practically all the material in this dissertation. I have certainly benefited from discussions with him concerning stellar models, primordial Li, and cos­ mology. He also kindly provided one of the isochrones shown in Chapter 3. I also thank him for his undying patience when my attention could not be focussed on our collaborative projects unrelated to my thesis. Additionally, I am grateful for his time and effort in writing job recommendations for IV me. Most of all, I have valued his friendship in offering me counsel, advice, and opinion. His and his wife Deborah's hospitality on several occasions have provided needed and enjoyable diversions from ordinary graduate student life. Also I should like to thank him for an enjoyable observing run in Chile and for preserving my life via his nimble (harrowing?) driving through the deathtraps that are the streets of Santiago. I have been financially supported the past three years by NSF grant AST-9016778 to Dr. Ann Boesgaard. CCD astronomy at the UH 2.2-m is supported by NSF grant AST-9020680. Mees Solar Observatory is supported by NSF grant AST-91l5038 and NASA grant NAGW 1542. Additionally, it is a genuine pleasure to acknowledge the gracious financial support of the Honolulu chapter of the ARCS Foundation, Inc. during my first four years at UH. Mss. Diane Tokumura and Georgette Albert are to be thanked for insulating me, to the extent possible, from the usual reams of senseless, onerous bureaucracy and getting me to where I had to go. The UH 2.2-m telescope operators, Mssrs. Dave Woodworth and Frank Cheigh, skillfully and repeatedly placed my objects on a 0.7" slit and offered much additional assistance. Dr. Andrew Pickles, the UH 2.2-m day crew, and the IfA machine shop also played important roles in making the UH 2.2-m observations discussed here possible. Dr. Richard Canfield allowed used of Mees Solar Observatory to obtain the solar observations discussed in Chapter 5; additionally, I am grateful to him for providing travel support to obtain the observations. Ms. Kristin Blais helped me utilize the IDL software package in the reduction of the solar data and wrote several useful codes for my benefit. She also bore the frustrating burden of trying to explain spatially scanning spectroscopy to a point-source spectroscopist. During my dissertation research, I have made extensive use of the SIMBAD database, operated at CDS, Strasbourg, France. I am grateful to the Kitt Peak National Observatory TAC for granting me time to perform the Hydra multi-object spectrograph observations. Full support of travel and observing expenses by KPNO is gratefully acknowledged. Dr. Sam Barden answered many qustions about Hydra prior to the run and his guidance during the early observations is appreciated. The KPNO observations would not have gone as smoothly as they did without the competent assistance of the LTO, Ms. Jennifer Hedden. Dr. Jeanette Barnes spent the good part of a day in Tucson leading me through the Hydra reductions. She and Dr. Caty Pilachowski also have answered numerous questions over the past few years concerning the reduction of spectra using IRAF. Dr. Kenneth Janes, who initially kindled my interest in stellar astronomy, kindly provided a CCD image of NGC 188 which allowed me to obtain the astrometry for the Hydra observations. He also provided me with his unpublished photometry of NGC 188. v I am extremely grateful to Dr. Robert Kurucz, who unselfishly provided me with his unpublished model atmospheres, colors, and Fe log gf values, with which much of the analysis presented here was conducted. Thanks are also due Dr. Monique Spite and Dr. Lewis Hobbs for providing me with several of their halo star spectra. Dr. Spite also aIIowed the use of and provided guidance with her LTE abundance software package, RAllO. Dr. Michael BesseII kindly provided me with several pages of his personal notes concerning the reanalysis of 0 abundances in giants. Dr. Eric Feigeison made his SLOPES software package available to me to perform the regressions discussed in Chapter 4. Dr. Pierre Demarque made his isochrones for NGC 188 available for my use in Chapter 6. Dr. Jocelyn Tomkin provided me with his LTE and NLTE solar calculations for the 0 I triplet. FinaIIy, I must express my appreciation to my family and friends. I have managed to maintain my (in)sanity over the past five years with the support, concern, and valued friendship of Kristin Blais, Dave Kane, Niki Kapsambelis, Nancy Kohrs, Emma Murray, Mark Nadeau, and Ron and Diane Nadeau. I wish to thank my extended family for their interest and support, which were valued more than they probably knew. Special thanks go to my sister Kathy. AdditionaIIy, my delightful nieces Janna and Jaime and my nephew Nathan have been a source of enduring inspiration as well as pride to me. Lastly, I should like to dedicate this dissertation to my parents, Philip and Millideen, who were (and are) the most influential teachers in my life. Their wisdom, encouragement, interest, and love have been immeasurably important to me.