Orbit-Dependent Spectral Trends for the Near-Earth Asteroid Population
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Orbit-Dependent Spectral Trends for the Near-Earth Asteroid Population Item Type text; Electronic Dissertation Authors Fevig, Ronald Adrey 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 02/10/2021 02:26:09 Link to Item http://hdl.handle.net/10150/195785 ORBIT-DEPENDENT SPECTRAL TRENDS FOR THE NEAR-EARTH ASTEROID POPULATION by Ronald Adrey Fevig _____________________ A Dissertation Submitted to the Faculty of the DEPARTMENT OF PLANETARY SCIENCES In Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY In the Graduate College THE UNIVERSITY OF ARIZONA 2006 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Dissertation Committee, we certify that we have read the dissertation prepared by Ronald Fevig entitled "Orbit-Dependent Spectral Trends for the Near-Earth Asteroid Population" and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy _______________________________________________________________________ Date: November 16, 2006 Uwe Fink _______________________________________________________________________ Date: November 16, 2006 Dante Lauretta _______________________________________________________________________ Date: November 16, 2006 Robert Brown _______________________________________________________________________ Date: November 16, 2006 Timothy Swindle _______________________________________________________________________ Date: November 16, 2006 Tom Gehrels 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: November 16, 2006 Dissertation Director: Uwe Fink 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. SIGNED: _________________________________ Ronald Adrey Fevig 4 ACKNOWLEDGEMENTS I thank my advisor, Dr. Uwe Fink, for patiently guiding me through the work associated with this dissertation. I thank NASA for funding this research through NASA Grants NAG 53937, NAG5- 12858 and NASA Training Grant NGT 550243. I thank Michael Hicks and Jim Scotti for many helpful conversations about near-Earth asteroids. I thank the faculty and staff of the Department of Planetary Sciences for providing an excellent research environment. I thank John Downs and Fred Floan for fostering my early educational development. I thank all of my family and friends who have supported and encouraged my endeavors. I thank my wife, Beth, for her patience and understanding while I pursued this degree. I thank my two daughters, Abigail and Nora. Their lessons have taught me volumes about life. 5 TABLE OF CONTENTS LIST OF FIGURES .............................................................................................................6 LIST OF TABLES...............................................................................................................8 ABSTRACT.........................................................................................................................9 1 INTRODUCTION .........................................................................................................11 2 OBSERVATIONS AND DATA REDUCTIONS.........................................................18 2.1 Instrumentation .......................................................................................................18 2.2 Observations ...........................................................................................................21 2.3 Data reduction.........................................................................................................23 3 SPECTRA AND THEIR CLASSIFICATION ..............................................................40 3.1 Method of classification..........................................................................................41 3.2 Spectra.....................................................................................................................50 3.3 The Bus classification method and Principal Component Analysis .......................56 4 ANALYSIS OF OUR SPECTRAL DATA ...................................................................59 4.1 The continuum of spectral types between OC-like and S-type NEAs....................60 4.2 Size-dependent trends .............................................................................................60 4.3 Orbit-dependent trends............................................................................................63 4.4 Summary.................................................................................................................73 5 OC-LIKE AND S-TYPE NEAS IN BINZEL ET AL. (2004a).................................... 75 5.1 Combining Binzel’s and our data into one data set using 40 NEAs observed in common by the two groups.....................................................................................76 5.2 Tabular form of asteroid classification comparison and statistical check ..............84 5.3 Classifying OC-like and S-type NEAs in Binzel et al. (2004a) using Principal Component Analysis by Bus (1999) of Gaffey (1976) meteorite data ...................89 5.4 The achondrite ambiguity .......................................................................................95 6 EXTINCT COMETS AMONG THE NEAR-EARTH ASTEROIDS...........................98 6.1 Trends in orbital inclination for Extinct Comet Candidates in our NEA dataset and Binzel et al.’s (2004a) ..................................................................................... 99 6.2 Extinct Comets within the NEA population .........................................................106 6.3 Conclusion ............................................................................................................112 6.4 Summary...............................................................................................................117 7 SUMMARY AND FUTURE WORK .........................................................................119 APPENDIX A: NEA SPECTRA FROM OUR SURVEY .............................................121 APPENDIX B: NOTES ON TAXONOMIC CLASSIFICATION ................................130 REFERENCES ................................................................................................................138 6 LIST OF FIGURES 2.1 CCD image showing object and sky windows ...........................................................27 2.2 Spatial profile..............................................................................................................29 2.3 Processing a CCD image ............................................................................................30 2.4 Preliminary spectrum..................................................................................................32 2.5 Ratioed spectra............................................................................................................34 2.6 Examples of high SNR spectra ...................................................................................36 2.7 Examples of low SNR spectra ....................................................................................37 3.1 Illustration of our spectral parameters ........................................................................42 3.2 NEA classification method .........................................................................................45 3.3 Examples of OC-like, S-type and meteorite spectra...................................................48 3.4 OC-like and R-type spectra grouped according to spectral parameters......................52 3.5 S-type and BOC-like spectra grouped according to spectral parameters ...................53 3.6 Spectra of objects which do not exhibit a 1-μm absorption........................................54 4.1 Slope vs. size and band depth vs. size for our NEAs..................................................62 4.2 Eccentricity vs. semi-major axis for S-type and OC-like NEAs (1).......................... 64 4.3 Aphelion distance vs. perihelion distance for S-type and OC-like NEAs (1) ........... 65 5.1 Principal Component plot of NEAs observed by both us and Binzel et al. (2004a) .....................................................................................................................................77 5.2 Classification