Georgia State University ScholarWorks @ Georgia State University Physics and Astronomy Theses Department of Physics and Astronomy 12-3-2007 SLOWMO: A Search for Nearby Stars Misty Adana Brown Follow this and additional works at: https://scholarworks.gsu.edu/phy_astr_theses Part of the Astrophysics and Astronomy Commons, and the Physics Commons Recommended Citation Brown, Misty Adana, "SLOWMO: A Search for Nearby Stars." Thesis, Georgia State University, 2007. https://scholarworks.gsu.edu/phy_astr_theses/4 This Thesis is brought to you for free and open access by the Department of Physics and Astronomy at ScholarWorks @ Georgia State University. It has been accepted for inclusion in Physics and Astronomy Theses by an authorized administrator of ScholarWorks @ Georgia State University. For more information, please contact [email protected]. SLOWMO: A Search for Nearby Stars by Misty Brown Under the Direction of Todd Henry Abstract I report on suspected nearby stars with proper motions 1.000 > µ ≥ 0.500/yr in the southern sky (DEC = −90◦ to 00◦). This sample of slow-motion (SLOWMO) stars complements the work of Jao (2004), who reported on faster moving stars with µ ≥ 1.000/yr in the entire sky for his doctoral dissertation, and the work of Finch et al. (2007), who uncovered stars moving slower than 0.500/yr between declinations −90◦ and −47◦. Characterizations of SLOWMO systems include trigonometric parallaxes, optical and infrared photometry. For stars without trigonometric parallaxes, colors and apparent magnitudes are used to calculate photometric distance estimates and the statistics of this population of stars are analyzed. The SLOWMO sample is comprised of 1906 total stars − 560 estimated to be less than 25 parsecs away, and 245 stars without parallaxes estimated to be within 25 parsecs. Index Words: Nearby Stars, Proper Motion Stars, Solar Neighborhood SLOWMO: A Search for Nearby Stars by Misty Brown A Thesis Presented in Partial Fulfillment of Requirements for the Degree of Master of Science in the College of Arts and Sciences Georgia State University 2007 Copyright by Misty Brown 2007 SLOWMO: A Search for Nearby Stars by Misty Brown Major Professor: Todd Henry Committee: Hal McAlister David Wingert Electronic Version Approved: Office of Graduate Studies College of Arts & Sciences Georgia State University December 2007 iv { 0 { Dedication This thesis is dedicated to my mother, who has made constant sacrifices so that I could be here. Also, in memory of Jeffrey Lynn Brown, Alfred John Wilbur, Douglas Elton Wilbur, and Samuel Paul Brown. Forever in my heart. v { 0 { Acknowledgments I wish to extend my sincere gratitude and appreciation to the multitude of people who helped make this dissertation possible. A very special thanks go to my adviser, Todd Henry, who allowed me the honor of working with such a talented group of astronomers. Without Dr. Henry's guidance, support and patience I would never be here, let alone have made it through. He is not only a stellar astronomer (ridiculous pun intended), but he is also one of the finest humans I have ever known. His enthusiasm for teaching, learning, and living are unbounded. I'd like to thank Dr. David Wingert and Dr. Hal McAlister, who were kind enough to agree to be on my committee. Although both men are very busy, they always answered questions promptly and were incredibly patient. Wei-Chun Jao and John Subasavage have been helpful since my very first day as an undergraduate working with Dr. Henry and have always been able to answer any question I have, even about things they're not responsible for! (e.g. The SIMBAD and 2MASS databases). John and Wei-Chun are also very helpful with anything having to do with linux, iraf, idl, etc. Also, a special thanks to Charlie Finch who has been particularly helpful in the nuts and bolts of the thesis as he went through this process just a few months earlier. He was like a mini-advisor! Justin Cantrell and Adric Riedel were extremely helpful in checking over JHK magnitudes for hundreds vi of stars and I wouldn't have been able to do it without them. I also want to thank Jen Winters for teaching me about photometry reduction and also for directing me to parallax papers. Nigel C. Hambly was always responsive to my queries regarding SuperCOSMOS. He generously provided all BRI magnitudes for my sample. I hear he also plays a mean saxophone. I'd like to thank Alvin Das for creating the LaTeX template for GSU astronomy dissertations and theses. He reinvented the wheel so I don't have to, and all future astronomy grad students will be indebted to him as well! He is also a great cook and was a wonderful roommate! Initially, I'd just intended to thank Raj Deo for keeping our computers running smoothly. That in itself is no small feat, especially for someone trying to meet his own dissertation deadlines. However, almost immediately after my thesis defense, our server had a meltdown and I was afraid I'd lost significant amounts of data. Raj had already moved to his new job, but he went out of his way to recover the data for me and I'm forever grateful to him for this. I am sure that in the chaos of thinking I had lost several days worth of very important work on this thesis and trying to redo it, more mistakes were made than I would have liked. The subsequent merging of new things I'd done without access to my old data was not helpful when dealing with ∼2000 stars, but I would have been infinitely worse off if Raj hadn't been able to get my data back and he is therefore my hero! Although pretty much everyone I vii know had to hear about this from me, I'd like to thank Kesh Harrison for patiently humoring me as I vented my frustrations about that situation and others. I would also like to give a super special thanks to David O'Brien for his endless love and personal support. He bore the brunt of my stress and took it all in stride. He is my rock. If that weren't enough, he even helped with checking JHK magnitudes and many other little things along the way, including some proofreading. I must also thank all of my family for being supportive and understanding through- out my schooling. I am very fortunate to have a close family that I can call on for pretty much anything at any time. I need to thank my mother Anita especially, but also my father, Danny. My mother instilled in me the belief that I could be whatever I wanted to be and always does everything she can to help me realize my goals. She is truly my best friend. My sister Julie is the best sister anyone could ask for and she proved it by bringing me care packages during some of the busier times. I also need to give special thanks to my second \mother", Aunt Brenda, and my grandmothers Muriel and Delilah, who always believed in me. The rest of my family − from cousins to aunts and uncles have also had a tremendous impact on my life and I wouldn't trade any of them for anything. Last but certainly not least, I'd like to thank all of the astronomers that came before me, especially those working on nearby stars. Without their careful recording and photographing of stars, my thesis would be empty. viii { 0 { Contents Acknowledgments . v List of Tables . x List of Figures . xvi Abbreviations and Acronyms . xvii 1 Introduction . 1 1.1 Proper Motion . 9 1.2 Trigonometric Parallax . 12 1.3 Photometric Distance Estimates . 13 1.4 Goals and Motivation . 14 2 Creating a Comprehensive List of SLOWMO Stars . 16 2.1 The Surveys . 16 2.2 Why this Range of Proper Motions and Declinations for SLOWMO? . 19 3 The Data . 26 3.1 Background . 26 3.2 Collected Data . 27 3.2.1 Coordinates . 27 3.2.2 BRI Photometry from plates . 28 3.2.3 V RI Photometry from CCDs . 30 3.2.4 JHK Photometry from 2MASS . 30 3.2.5 Trigonometric Parallaxes . 31 ix 3.3 New Data . 32 3.3.1 VRI Photometry from CTIO . 32 3.3.2 Trigonometric Parallaxes from CTIO . 51 4 Analysis . 53 4.1 Distance Estimates using BRIJHK . 53 4.2 Distance Estimates using V RIJHK . 55 4.3 Population Statistics . 57 4.4 Multiple Systems . 60 5 Discussion . 63 5.1 New Common Proper Motion Companions to Previously Known Stars 64 5.2 Stars Previously Unknown to be Within 25 pc . 65 5.3 Newly Discovered White Dwarfs . 67 5.4 Subdwarfs . 68 5.5 Just Passing Through the Galaxy? . 70 5.6 Conclusions . 72 References . 75 Appendices . 81 A Statistics at a Glance . 82 B Photometry, Astrometry, and Photometric Distance Estimates for the SLOWMO Sample . 83 C Finders Charts for Multiple Star Systems and Stars of Interest. 138 x { 0 { List of Tables 1.1 Extrasolar Planets Summary. 7 2.1 Proper Motion Surveys and Number of Stars in SLOWMO Sample. 18 3.1 Photometry and Distance Estimates for Members of the SLOWMO Sample Estimated to be within 25 pc using BRIJHK Photometry, and comparisons to distances using V RIJHK Photometry and Trigono- metric Parallaxes . 34 B.1 Photometry, Astrometry, and Photometric Distance Estimates for the SLOWMO Sample . 84 xi { 0 { List of Figures 1.1 An Example of a Star showing proper motion- Proxima Centauri . 11 2.1 Sky Distribution of SLOWMO Stars. 19 3.1 Parallax coverage of SLOWMO Sample . 52 4.1 Photometric Distance Estimates of SLOWMO Sample .