Observations and Models of Infrared Debris Disk Signatures and Their Evolution
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Observations and Models of Infrared Debris Disk Signatures and their Evolution Item Type text; Electronic Dissertation Authors Gaspar, Andras 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 07/10/2021 14:47:51 Link to Item http://hdl.handle.net/10150/202982 OBSERVATIONS AND MODELS OF INFRARED DEBRIS DISK SIGNATURES AND THEIR EVOLUTION by Andr´as G´asp´ar 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 2011 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Dissertation Committee, we certify that we have read the dissertation prepared by Andr´as G´asp´ar entitled “Observations and models of infrared debris disk signatures and their evolution” and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy. Date: 3 November 2011 Dr. George Rieke Date: 3 November 2011 Dr. Dimitrios Psaltis Date: 3 November 2011 Dr. Feryal Ozel¨ Date: 3 November 2011 Dr. Kate Y. L. Su Date: 3 November 2011 Dr. D´aniel Apai Final approval and acceptance of this dissertation is contingent upon the candi- date’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: 3 November 2011 Dissertation Director: Dr. George Rieke 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 Univer- sity Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permis- sion, 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. SIGNED: Andr´as G´asp´ar 4 ACKNOWLEDGMENTS The path one walks down to reach the stage in life where they can actually sit down to write an acknowledgment for their doctoral thesis is extremely long, full of curves and obstacles. Along the way, I have met so many people that have influenced, guided, and helped me that listing them all is mere impossible and would over-tower the thesis itself. The credit for teaching me how to write properly goes out to my Mother, who put a lot of effort into teaching me about languages and literature. Obviously, the biggest influence was that of my Father, who being a physical-chemist him- self, always bestowed the logic of a scientist on me and allowed me to pursuit and nurtured all of the interests I developed over the years. My elementary and high school physics teachers, Mih´aly Kotorm´an and Dr. Ervin Szegedi, were also invaluable in opening my eyes to the wonderful world of physics. I have great deal of appreciation for all my previous advisors who took upon the task of advising me. If it were not for Dr. L´aszl´oL. Kiss, I would definitely not have started doing research as early as I have and maybe not even in astronomy. He taught me all the initial tools an astronomer needs to know and that I still use today. Dr. Zolt´an Balog was not only a great advisor, but also a friend who I could and still can count on. It was absolutely his influence that I started working in infrared astronomy and that I applied to the University of Arizona later on. I am also thankful for Dr. Melvin G. Hoare for giving me an opportunity to work on the Science Verification phase of the UKIDSS project in Leeds, in the summer of 2005. I also thank Kate Su for the help she gave with my first two papers at Steward. I am grateful to Dr. Dimitrios Psaltis and Dr. Feryal Ozel¨ for teaching me how to correctly and professionally approach a numerical coding project and for devoting all the time they did to the final part of my thesis. Without their help this thesis would have turned out differently. I do have many people to thank and acknowledge. One special person how- ever, my advisor Dr. George Rieke, does stands out from the crowd. He has, next to his vast amount of duties, somehow always found time to advise me. He always gave just the right amount of a push to get me going and always took interest in my personal problems. He is someone who genuinely cares how his students are doing. He always has and always will inspire me. Last, but not least, I thank all my friends who have been part of my life and supported me over the years. Zolt´an Makai, Suresh Sivanandam, Dennis Just, Alan Cooney and many others, thank you for all the fun times! And thank you, my best friend, my dear wife, Bori, for everything, for your support, your under- standing and all the joy I have gotten over the years. You make all this work and invested time have a meaning. Thank you. 5 DEDICATION I dedicate this thesis to my past, my present and my future. My past being my grandparents, who have all taught me so many valuable lessons in life and how to be a good person. They will always be an example to follow. My present being my mother, Ir´en, my father, Vilmos, my sister, Judit and my wife, Bori. You have been with me throughout the struggles and the joyous moments. You have encouraged me and given me goals to reach. And my future being our little baby, whom I don’t even know yet, but cannot wait to see in February. You and Mommy are the single reason this is all worth doing. 6 TABLE OF CONTENTS LIST OF FIGURES ................................ 9 LIST OF TABLES ................................. 11 ABSTRACT .................................... 12 CHAPTER 1 INTRODUCTION .......................... 14 1.1 Motivation................................. 14 1.2 Extrasolarplanets............................. 15 1.3 Starandplanetformation . 18 1.4 Circumstellardebrisdisks . 24 1.5 Thesolarsystem’sdebrisdisk . 26 1.6 Outlineofthethesis............................ 27 CHAPTER 2 FALSE SIGNS OF DEBRIS DISKS .................. 29 2.1 Introduction ................................ 29 2.2 ObservationsandDataReduction . 32 2.3 TheBowShockModel .......................... 37 2.3.1 Physicaldescriptionofthemodel . 38 2.3.2 ModelGeometryandParameters. 40 2.3.3 Results............................... 42 2.4 Discussion ................................. 50 2.4.1 BowShockModelResults . 50 2.4.2 ISMInteractions ......................... 52 2.4.3 Implications for Diffusion/Accretion Model of λ Bo¨otis Phe- nomenon.............................. 54 2.5 Summary.................................. 55 CHAPTER 3 DEBRIS DISK STUDY OF PRAESEPE ................ 57 3.1 Introduction ................................ 58 3.2 Observations, data reduction, and photometry . .... 61 3.3 Catalogsurveysandthefinalsample. 64 3.4 Results ................................... 74 3.4.1 Color-colorselection . 74 3.4.2 TheSEDfitselection . 81 3.4.3 Praesepewhitedwarfs. 81 3.4.4 DebrisDiskCandidates . 81 3.5 Discussion ................................. 84 3.5.1 Calulatingerrorsondebrisdiskfractions . .. 85 3.5.2 The decay of the debris disk fraction in early-type stars... 86 3.5.3 The decay of the debris disk fraction for solar-type stars .. 89 7 TABLE OF CONTENTS — Continued 3.5.4 Evolutionary differences between the debris disks around early-andsolar-typestars . 92 3.5.5 The results in context with the Late Heavy Bombardment . 95 3.6 Summary.................................. 97 CHAPTER 4 MODELING COLLISIONAL CASCADES IN DEBRIS DISKS .... 102 4.1 Introduction ................................102 4.2 The physical and numerical challenges of modeling debrisdisks . 105 4.2.1 Collisionaloutcomes . 110 4.2.2 Incorporating the complete redistribution integral ...... 112 4.2.3 Theeffectofradiationforces . 112 4.3 Thecollisionalmodel. 113 4.3.1 Theevolutionequation . 114 4.3.2 Thecollisionalterm . 118 4.3.3 Collisionoutcomes . 120 4.3.4 The initial distribution and fiducial parameters . 125 4.4 SimplifiedDynamics . 125 4.4.1 Collisionalvelocities . 128 4.4.2 Reduced collisional probabilities of β critical particles . 129 4.4.3 Reduced collisional probabilities of the largest particles . 131 4.5 Results ...................................132 4.5.1 ComparisontoTh´ebaultetal.(2003) . 133 4.5.2 Comparison to L¨ohne et al. (2008) and Wyatt et al. (2011) . 137 4.6 Conclusions ................................145 CHAPTER 5 STEEP DUST-SIZE DISTRIBUTIONS ................ 146 5.1 Introduction ................................146 5.2 Numericalmodeling . 147 5.2.1 Evolutionofthereferencemodel . 148 5.2.2 The dependence of the steady-state distribution function on thecollisionparameters . 152 5.2.3 The dependence of the steady-state distribution function on systemvariables . .. .. .. .. .. .. 156 5.2.4 The dependence of the steady-state distribution function on numericalparameters . 157 5.2.5 Thetimetoreachsteady-state. 158 5.2.6 Therobustnessofthesolution . 159 5.3 SyntheticSpectra ............................