CARBON-MONOXIDE ABSORPTION IN K AND M GIANTS AND THE CARBON-12/CARBON-13 ABUNDANCE RATIO Item Type text; Dissertation-Reproduction (electronic) Authors Bailey, Wayne Lewis, 1942- 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 23/09/2021 15:08:21 Link to Item http://hdl.handle.net/10150/290269 71-24,887 BAILEY, Wayne Lewis, 1942- CARBON MONOXIDE ABSORPTION IN K AND M GIANTS AND THE C12/C13 ABUNDANCE RATIO. The University of Arizona, Ph.D., 1971 Astrophysics University Microfilms, A XEROX Company, Ann Arbor, Michigan THIS DISSERTATION HAS BEEN MICROFILMED EXACTLY AS RECEIVED CARBON MONOXIDE ABSORPTION IN K AND M GIANTS AND THE C12/C13 ABUNDANCE RATIO by Wayne Lewis Bailey A Dissertation Submitted to the Faculty of the DEPARTMENT OF ASTRONOMY In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 19 7 1 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE I hereby recommend that this dissertation prepared under my direction by Wayne Lewis Bailey entitled Carbon Monoxide Absorption in K and M Giants and the C*VC*3 Abundance Ratio be accepted as fulfilling the dissertation requirement of the degree of Doctor of Philosophy Dissertation Director f Date/7 After inspection of the final copy of the dissertation, the following members of the Final Examination Committee concur in its approval and recommend its acceptance:* P {.i/flo. * /9 ftpJL 1971 —j-—~ •jr-.yj ^./ 7 19^1 "This approval and acceptance is contingent on the candidate's adequate performance and defense of this dissertation at the final oral examination. The inclusion of this sheet bound into the library copy of the dissertation is evidence of satisfactory performance at the final examination. PLEASE NOTE: Some pages have small and indistinct type. Filmed as received. University Microfilms 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 bor­ rowers 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 re­ production 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 judgment the proposed use of the material is in the in­ terests of scholarship. In all other instances, however, permission must be obtained from the author. SIGNED: ACKNOWLEDGMENTS The author would like to express his gratitude to the following people who have provided assistance in the completion of this disserta­ tion: The staff of the University of Arizona Computer Center and particularly Mr. Steve Jay for their assistance with the computation of the synthetic spectra; Mr. Richard I. Mitchell for his assistance in preparing the stellar spectra for analysis; Dr. Thomas L. Swihart for supplying advice and encouragement while the work was being carried out and for critically reading the manu­ script and offering many useful suggestions for its improvement; Dr. Harold L. Johnson for supplying the stellar spectra as well as his advice and encouragement throughout all phases of the work; Dr. Rodger I. Thompson, the dissertation director, for his enthusiasm and advice while the work was in progress as well as offer­ ing many suggestions for improvement of the manuscript; and my wife, Deborah, for her assistance with the tedious, mechanical details involved in the completion of this dissertation and for cheerfully tolerating the disruptions to a normal existence that are a part of any PhD program. iii TABLE OF CONTENTS Page LIST OF ILLUSTRATIONS vi LIST OF TABLES ix ABSTRACT x INTRODUCTION ! The Carbon Isotope Abundances 3 The CNO Bi-cycle 6 Carbon Monoxide 7 The Present Investigation 9 THE SYNTHETIC SPECTRA 12 Theory of the Curve of Growth 13 Procedure 19 Blended Lines 21 Interpretation of a 21 The Grid of Synthetic Spectra 23 The Curves of Growth 34 THE STELLAR SPECTRA 50 Sources of Error 52 Noise 52 Other Absorptions 53 Placement of the Continuum 54 The Method of Analysis 56 The Isotope Ratio analysis 76 Results 76 Alpha Bootis 79 Gamma Draconis 80 Alpha Tauri. 82 Delta Ophiuchi 83 Beta Pegasi 83 Eta Geminorum 84 Mu Geminorum 85 iv V TABLE OF CONTENTS—Continued Page Rho Persei 8® R Lyrae 86 EU Delphini 87 Alpha Orionis 88 Alpha Scorpii 88 Mu Cephei 89 Delta2 Lyrae 90 Alpha Herculis 91 SUMMARY AND CONCLUSIONS 93 The Carbon Isotope Ratio 93 The Carbon Monoxide Abundance 95 The Assumption of Local Thermodynamic Equilibrium ... 95 The Continuous Opacity 96 Results 98 Relation to Theoretical Models 98 Nucleosynthesis 100 Convection • 104 Results 106 Summary and Suggestions for Further Research 107 APPENDIX A: CALCULATION OF Sm AT ARBITRARY TEMPERATURES ANDC^/C13, 016/018 RATIOS 110 APPENDIX B: PARTITION FUNCTIONS FOR CARBON MONOXIDE .... 113 APPENDIX C: BAND ORIGINS AND BAND HEADS FOR THE FIRST AND SECOND OVERTONE VIBRATION-ROTATION BAND OF C12C16, C13016 AND C12018 115 REFERENCES 118 LIST OF ILLUSTRATIONS Figure Page 1. Milne-Eddington Curves of Growth 18 2. Synthetic Spectra; Temperature Sequence with log a = -3 ... 24 31. Synthetic Spectra; Temperature Sequence with log a= -1 ... 25 4. Synthetic Spectra; Damping Parameter Sequence 26 5. Synthetic Spectra;, Microturbulent Velocity Sequence 27 6. Synthetic Spectra; Temperature Sequence with Linear Curve of Growth 28 7. Synthetic Spectra; Abundance Sequence with T = 2500 K . ... 29 8. Synthetic Spectra; Abundance Sequence with T =4500 K. 30 9. Synthetic Spectra; Isotope Ratio Sequence 31 10. Curve of Growth for the Region 4036-4360 cm-* with T = 2500 K 35 11. Curve of Growth for the Region 4036-4360 cm~* with T = 3500 K 36 12. Curve of Growth for the Region 4036-4360 cm~* with T = 4500 K 37 13. Curve of Growth for the C^O^ (3-1) Band Head with T = 2500 K 40 14. Curve of Growth for the C^O^ (3-1) Band Head with T = 3500 K 41 15. Curve of Growth for the C^O*® (3-1) Band Head with T = 4500 K . 42 vi vii LIST OF ILLUSTRATIONS—Continued Figure Page 16. Curve of Growth for the C*30^ (2-0) Band Head with T = 2500 K 43 17. Curve of Growth for the C*30^ (2-0) Band Head with T = 3500 K 44 18. Curve of Growth for the C*30*® (2-0) Band Head with T = 4500 K 45 19. W13/W12 - C12/C13 for a Linear Curve of Growth 46 20. W13/W12 - C12/C13 for T = 2500 K 47 21. W13/W12 - C12/C13 for T = 3500 K 48 22. W13/W12 - C12/C13 for T = 4500 K 49 23. C*2/C*3 - log i ; Alpha Bootis 57 24. C*2/C*3 - log ; Gamma Draconis and Alpha Scorpii .... 58 25. C12/C13 - log •> ; Alpha Tauri 59 26. C12/C13 - log <» ; Delta Ophiuchi 60 27. C12/C13 - log i ; Beta Pegasi 61 28. C*2/C*3 - logi ; Eta Geminorum .............. 62 29. C12/C13 - log*) ; Mu Geminorum 63 30. C^2/C^3 - log ; Rho Persei 64 31. Cl2/Cl3 - log^ ; R Lyrae 65 32- C12/C13 - log•) ; EU Delphini . 66 33. C12/C13 - log>? ; Alpha Orionis 67 viii LIST OF ILLUSTRATIONS—Continued Figure Page 34. C12/C13 - log 7 ; Mu Cephei 68 35. C12/C13 - log ^ ; Delta2 Lyrae 69 36. C^2/cl3 - log tj ; Alpha Herculis 70 37. Log <7 - Alpha Bootis, Gamma Draconis, Alpha Tauri and Delta Ophiuchi 71 38. Log - BQ/B^; Beta Pegasi, Eta Geminorum, Mu Geminorum and Rho Persei 72 39. Log ^ - BQ/BJ; R Lyrae, EU Delphini, Alpha Orionis and Alpha Scorpii 73 40. Log fj - BQ/BJ ; Mu Cephei, Delta2 Lyrae and Alpha Herculis 74 41. Carbon Isotope Ratios in Stars 94 42. Fractional Equilibrium Abundances of CNO Nuclei 102 43. Equilibrium Isotope Ratios of CNO Nuclei 103 44. Fractional Abundances of CNO Nuclei During the Approach to Equilibrium 105 LIST OF TABLES Table Page 1. Polynomial Approximations to the Curves of Growth 17 2. Spectra Used in this Investigation 51 3. Measured Equivalent Widths of CO AV = 2 Band Sequence and the Ratio of the Cl3c>16 and q12o16 Band Heads • • 77 4. Stellar Results 78 5. The CNO Bi-cycle 101 ix ABSTRACT The second overtone vibration-rotation bands of carbon monox- 1 0 1 ide are used to determine the C /C abundance ratio in fifteen stars of spectral types K2 through M6, luminosity classes III through la. The relation of the results to theoretical studies of the structure of evolved stars is discussed. Twenty three spectra of the fifteen stars, covering the wavenumber region 3900-8200 cm-* or 2400-8200 cm~* with a resolution of 8 cm~* are analyzed. A grid of synthetic carbon monoxide spectra is calculated using 1 n 1 O a Milne-Eddington curve of growth, for various values of C /C ratio, temperature, microturbulent velocity and damping parameter. These synthetic spectra are used to construct curves of growth for the band heads which are used to determine the C^/C-^ ratio from the stellar spectra. The C12/C13 ratio is significantly lower than the terrestrial value in all stars studied. This is interpreted as an indication that material, which has been processed through the CNO bi-cycle, has been transported from the interiors to the surfaces of the stars.