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Proquest Dissertations Constraints on the surface composition of Trojan asteroidsfrom near infrared (0.8-4.0 μm) spectroscopy and spectral modeling Item Type text; Dissertation-Reproduction (electronic) Authors Emery, Joshua P. 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 06/10/2021 12:07:38 Link to Item http://hdl.handle.net/10150/280170 INFORMATION TO USERS This manuscript has t)een 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 bleedthrough, 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. ProQuest Information and Learning 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 800-521-0600 NOTE TO USERS Page(s) missing in number only; text follows. The manuscript was microfilmed as received. 12 This reproduction is the best copy available. UMI' CONSTRAINTS ON THE SURFACE COMPOSITION OF TROJAN ASTEROIDS FROM NEAR INFRARED (0.8 - 4.0 ^m) SPECTROSCOPY AND SPECTRAL MODELING by Joshua Patrick Emery A Dissertation Submitted to the Faculty of the DEPARTMENT OF PLANETARY SCENCES In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 2002 UMI Number; 3073216 ® UMI UMI Microform 3073216 Copyright 2003 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor. Ml 48106-1346 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Final Examination Committee, we certify that we have read the dissertation prepared by Joshua P. Emery entitled Constraints on the Surface Composition of Troian Asteroids from Near Infrared (0.8 - 2.4 Lim) Spectroscopy and Spectral Modeling and recommend that it be accepted as fulfilling the dissertation requirements for the Degree of Doctor of Philosophy // R. Date 0 Date /2.•/uh?. Date Date 11-AJosf C. G. Chase Date Final approval and acceptance of this dissertation is contingent upon the candidate's submission of the final copy of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommerjj^hat it be accept^ as fulfilling the dissertation requirement. Dissertation Director Dafe 3 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of the 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 acknowledgement 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 interest of scholarship. In all other instances, however, permission must be obtained from the author. SIGNED: 4 ACKNOWLEDGEMENTS Before and during my tenure at LPL. my family and friends had often asked me exactly what the point of graduate school is. Initially I'd just shrug, with a vacant, unknowing expression on my face. After a few years. I might mumble something about gaining experience and intuition or learning to perform independent scientific research. Now that I'm at the end of my graduate career, however. I can clearly see that graduate school is just one prolonged psychological experiment. The PhD is only bestowed when you're no longer entirely (or even mostly) sane. As such, the support, care, guidance, motivation, and friendship of many people have been recognized, and some undeniably insufficient acknowledgement for those efforts is given here, though undoubtedly some will be left out. First and foremost. Karen has been a part of my life ever since I entered graduate school. She provided love and support throughout my time at LPL. It's hard to imagine what the past n years may have been like without her. and I will be forever grateful. My advisor. Bob Brown, gave me the latitude and time to discover my own interests and confidence in my research. In a remarkable balancing act, he was also always open with his time and advice. I would also like to acknowledge Ann Sprague. who proved to be a wonderful friend and colleague. She provided helpful advice and a listening ear for both scientific and personal issues, and has exuded an excitement for science (especially Mercury!) that is refreshing and motivating. Several people graciously accepted a free trip to Hawaii to help me at the telescope and are partially responsible for the good data and fully responsible for any bad data, so thank you Andy. Matt. Pete, and Dave. George and Marcia Rieke. the staff of the IRTF. especially the telescope operators, and the staff at the MMT were also kindly assisted with the data collection. I've had three interestingly unique office mates here at LPL. Unfortunately, this often led to more conversing than working in the office. Without Pete, I probably would have finished 2 years earlier and 50% less insane, and I'll never look at chicken wings or pianos the same again. Eric's romantic exploits gave Pete and I much needed entertainment. Jonathan's sense of humor, contagious laughter, and shared interest in golf and baseball have been a fine counterbalance to Pete's insanity. There are. of course, many others. The Everyday Beers crowd: Ralph, Pete, Dave, Jason. Fred. Gwen. Carl, Curtis, Joe, Rob, Ingrid, Gareth, and Jani. The softball crowd: Jonathan. Jason, the guys from the Red Garter, and the Sunday morning crew. Other remarkable friends: Greg, Nancy. Dave, Cynthia, Ron. Betty. Zibi, Paul, Matt. Matt, .Abby. Devon, Barb, Rachel, Ross, Kevin, and all those I've left out because I'm writing this at the last minute. Last, but certainly not least, my family is a remarkably stable and enduring source of support, even when they (and sometimes I) don't understand quite what it is I'm doing. They may not realize it. but many of the qualities that have led to success for me so far have been instilled by them. So Mom, Dad, Cathy Ann, Mary, Ruth, and Skye, thank you. 5 TABLE OF CONTENTS LIST OF RGURES 8 LIST OF TABLES 11 ABSTRACT 13 1 INTRODUCTION 15 1.1 Motivation 15 1.2 Overview of the Solar System 16 1.3 Previous Studies of Asteroids and Other Small Bodies 21 1.4 Previous Studies of Trojan Asteroids 27 1.5 Chemistry of the Solar Nebula 29 1.6 Outline of Present Work 32 2 OBSERVATIONS OF TROJAN ASTEROIDS 35 2.1 Introduction 35 2.2 Observations 37 2.3 Data Reduction 40 2.4 Description of Data 46 2.4.1 IRTF Fall 1999-NSFCAM 46 2.4.2 IRTF Fall 2000 - SpeX 52 2.4.3 IRTF Spring 2001-SpeX 52 2.4.4 MMT Spring 2001 - SpeX 58 2.4.5 IRTF Fall 2001 - SpeX 59 2.4.6 IRTF Spring 2002 - SpeX 61 2.5 Analysis 68 2.5.1 Possible Surface Components 68 2.5.2 Absorption features in Trojan Spectra 75 2.5.2.1 617Patroclus 76 2.5.2.2 J- and H-band 79 2.5.2.3 5144 Achates 81 2.5.2.4 588 Achilles 81 2.5.2.5 911 Agamemnon 83 2.5.2.6 2797 Teucer 85 2.5.3 Multiple Spectra of the Same Object 86 2.5.4 Spectral Slope 91 2.5.5 K- and L-band Sums 98 2.6 Discussion 100 2.6.1 Space Weathering 101 2.6.2 Water Ice 103 2.6.3 Hydrated Silicates 104 2.6.4 Possible Absorptions 105 2.6.5 Spectral Slope 107 2.7 Conclusion 108 6 TABLE OF CONTENTS - Continued 3 SPECTRAL MODELING OF TROJAN ASTEROID DATA Ill 3.1 Introduction Ill 3.2 Model Description 114 3.2.1 Hapke Scattering Theory 114 3.2.2 Phase Functions/Phase Reddening 120 3.2.3 Optical Constants 121 3.2.4 Technique 123 3.3 Data 125 3.4 Model Runs 128 3.4.1 Pure Materials and Grain Diameter Dependences 128 3.4.1.1 Pyroxene 129 3.4.1.2 Olivine 134 3.4.1.3 Carbon Species 136 3.4.1.4 Organics 138 3.4.1.5 Water Ice and Hydrated Silicates 142 3.4.2 Three-Component Data Fits 145 3.4.2.1 624Hektor 147 3.4.2.2 588 Achilles 155 3.4.2.3 617Patroclus 157 3.4.2.4 911 Agamemnon 159 3.4.2.5 1143 Odysseus 161 3.4.2.6 lI72Aneas 163 3.4.2.7 1437 Diomedes 164 3.4.2.8 1867 Deiphobus 166 3.4.2.9 2759 Idomeneus 168 3.4.2.10 2797Teucer 170 3.4.2.11 3540 Protesilaos 172 3.4.2.12 3793 Leonteus 173 3.4.2.13 4060Deipylos 175 3.4.2.14 4063 Euforbo 176 3.4.2.15 4835 1989 BQ 178 3.4.2.16 5144 Achates 179 3.4.2.17 5254 Ulysses 181 3.4.3 Discussion of Three-Component Model Results 183 3.4.4 Four-Component Models 189 3.4.5 Limits on Organic Abundance 194 3.4.6 Limits on Water Ice and Hydrated
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