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Laboratory Spectroscopy and Radio Astronomical MILLIMETER WAVE STUDIES OF CIRCUMSTELLAR CHEMISTRY Item Type text; Electronic Dissertation Authors Tenenbaum, Emily Dale Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 08/10/2021 19:59:58 Link to Item http://hdl.handle.net/10150/194941 1 MILLIMETER WAVE STUDIES OF CIRCUMSTELLAR CHEMISTRY by Emily Dale Tenenbaum _____________________ A Dissertation Submitted to the Faculty of the DEPARTMENT OF CHEMISTRY In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 2010 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Dissertation Committee, we certify that we have read the dissertation prepared by Emily Dale Tenenbaum entitled Millimeter Wave Studies of Circumstellar Chemistry and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy _______________________________________________________________________ Date: April 12, 2010 Dr. Lucy M. Ziurys _______________________________________________________________________ Date: April 12, 2010 Dr. Andrei Sanov _______________________________________________________________________ Date: April 12, 2010 Dr. Oliver Monti _______________________________________________________________________ Date: April 12, 2010 Dr. Chris Walker _______________________________________________________________________ Date: April 12, 2010 Dr. John H. Bieging Final approval and acceptance of this dissertation is contingent upon the candidate’s submission of the final copies of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement. ________________________________________________ Date: April 12, 2010 Dissertation Director: Dr. Lucy M. Ziurys 3 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at the University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author. Emily Dale Tenenbaum 4 ACKNOWLEDGEMENTS I would like to acknowledge my advisor Prof. Lucy Ziurys for her guidance, encouragement, passion for scientific discovery, and friendship. I am grateful for my husband, Michele, for his companionship, support, positive outlook, and humor. Also for my daughter Francesca, whose excellent behavior and pleasant demeanor has made the timely completion of this dissertation possible. And also for my parents, Ellen and Bernie, and siblings, Danny and Karen, for all the fun-filled visits they paid to Tucson. I acknowledge the other members of the Ziurys group, current and former, for their friendship, training, answering questions, and being good company down in the basement of Steward Observatory. In particular I thank Robin Pulliam for helping with the ZnCl project, Mike Flory for training me in the lab, Stefanie Milam for training me to use the telescopes, and DeWayne Halfen and Aldo Apponi for instruction in many areas of research including the use of fitting programs, observing with the IRAM 30 m, and rotational diagrams. Finally I acknowledge the ARO telescope operators, engineers, and support staff for keeping the SMT and 12 m running while I collected data. I will always remember lively conversations up on Mt. Graham and Kitt Peak with the operators Bob Moulton., John Downey, Sean Keel, Mike Begam, Mike Soukup, Ron Mastaler, and Patrick Fimbres. Thank you to Tom Folkers for cheerily responding to all my reports of problems, and the engineers George Reiland, Bob Freund, Dave Forbes, and Martin McColl for their helpful explanations of instrumentation, and skilled maintenance and upgrade efforts on the telescopes. 5 TABLE OF CONTENTS LIST OF FIGURES ........................................................................................................... 7 LIST OF TABLES ............................................................................................................. 8 ABSTRACT ........................................................................................................................9 CHAPTER 1. INTRODUCTION ................................................................................... 10 CHAPTER 2. TELESCOPE INSTRUMENTATION..................................................... 13 a. The Submillimeter Telescope………………………..................................... 13 b. Beam Efficiency Measurements at the Submillimeter Telescope ................. 15 CHAPTER 3. RADIATIVE TRANSFER ANALYSIS ..……………………………....18 a. Rotational Diagram Method ...………………………………………………18 b. Non-Local Thermodynamic Equilibrium Modeling ...………………………30 CHAPTER 4. CHEMISTRY IN CIRCUMSTELLAR ENVELOPES ...……………….33 a. 1 mm Survey of IRC +10216 and VY Canis Majoris ...…………………….34 b. New Molecules – PO, AlOH, AlO, PH3, CH2NH... ………………………...37 CHAPTER 5. CHEMISTRY IN AN EVOLVED PLANETARY NEBULA ………….40 CHAPTER 6. COMMERCIAL POTENTIAL OF THz SPECTROSCOPY……………42 a. Technology Behind THz Spectroscopy……………………………………...42 b. Applications in Pharmaceutical Manufacturing……………………………..45 c. Case Study: Teraview………………………………………………………..47 APPENDIX A. DETECTION OF C3O IN IRC +10216: OXYGEN-CARBON CHAIN CHEMISTRY IN THE OUTER ENVELOPE …....................................50 APPENDIX B. A SEARCH FOR PHOSPHINE IN CIRCUMSTELLAR ENVELOPES: PH3 IN IRC +10216 AND CRL 2688?............…....................................55 APPENDIX C. MILLIMETER DETECTION OF AlO (X2∑+): METAL OXIDE CHEMISTRY IN THE ENVELOPE OF VY CANIS MAJORIS ...........60 2 APPENDIX D. IDENTIFICATION OF PHOSPHORUS MONOXIDE (X ∏r) IN VY CANIS MAJORIS: DETECTION OF THE FIRST P-O BOND IN SPACE……………………………………………………………..........66 APPENDIX E. EXOTIC METAL MOLECULES IN OXYGEN-RICH ENVELOPES: DETECTION OF AlOH (X1∑+) IN VY CANIS MAJORIS....................71 6 TABLE OF CONTENTS - Continued APPENDIX F. CARBON CHEMISTRY IN THE ENVELOPE OF VY CANIS MAJORIS: IMPLICATIONS FOR OXYGEN-RICH EVOLVED STARS…………………………………………………………………..77 APPENDIX G. MOLECULAR SURVIVAL IN EVOLVED PLANETARY NEBULAE: DETECTION OF H2CO, c-C3H2, AND C2H IN THE HELIX….….......88 APPENDIX H. THE ARIZONA RADIO OBSERVATORY 1 MM SPECTRAL SURVEY OF IRC +10216 AND VY CANIS MAJORIS (215-285 GHZ)…………………………………………………………………….94 APPENDIX I. THE COMPARATIVE CHEMISTRIES OF OXYGEN-RICH VS. CARBON-RICH CIRCUMSTELLAR SHELLS: VY CANIS MAJORIS AND IRC +10216 AT 215-285 GHZ…………………………….……216 APPENDIX J. THE PURE ROTATIONAL SPECTRUM OF ZnCl (X2∑+): VARIATIONS IN ZINC HALIDE BONDING……………………….240 REFERENCES ...............................................................................................................247 7 LIST OF FIGURES Figure 1. Design of the SMT 1 mm Sideband Separating Mixer..................................... 14 Figure 2. SMT Beam Efficiencies Across the 1 mm Band……....................................... 17 Figure 3. Basic Schematic of Radiative Transfer………………..................................... 18 Figure 4. Rotational Diagram of C3O Emission in IRC +10216...................................... 29 Figure 5. Overview of the 1 mm Survey of IRC +10216 and VY CMa........................... 35 Figure 6. Diagram of a Terahertz Spectrometer Design………....................................... 44 Figure 7. Terahertz Spectra of Common Powder Explosives…....................................... 44 8 LIST OF TABLES Table 1. SMT 1 mm Receiver Beam Efficiencies………………………….................... 17 Table 2. Expressions of the Dipole Moment Matrix Element for Different Molecular Geometries……………………………......……………………….................... 27 9 ABSTRACT Millimeter wave studies of molecules in circumstellar envelopes and a planetary nebula have been conducted. Using the Submillimeter Telescope (SMT) of the Arizona Radio Observatory (ARO) on Mt. Graham, a comparative spectral survey from 215-285 GHz was carried out of the carbon-rich asymptotic giant branch star IRC +10216 and the oxygen-rich supergiant VY Canis Majoris. A total of 858 emission lines were observed in both objects, arising from 40 different molecules. In VY Canis Majoris, AlO, AlOH, and PO were detected for the first time in interstellar space. In IRC +10216, PH3 was detected for the first time beyond the solar system, and C3O, and CH2NH were found for the first time in a circumstellar envelope. Additionally, in the evolved planetary nebula, the Helix, H2CO, C2H, and cyclic-C3H2 were observed using the SMT and the Kitt Peak 12 m telescopes. The presence of these three molecules in the Helix suggests that relatively complex chemistry occurs in planetary nebulae, despite the harsh ultraviolet field. Overall, the research on molecules in circumstellar and planetary nebulae furthers
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