Milliarcsecond Resolution Infrared Observations of the Recurrent Nova RS Ophiuchi and Low Mass Stellar Systems by Richard Keith Barry, Jr. A dissertation submitted to The Johns Hopkins University in conformity with the requirements for the degree of Doctor of Philosophy. Baltimore, Maryland January, 2008 c Richard Keith Barry, Jr. 2008 All rights reserved Abstract We introduce the method of long-baseline stellar interferometry starting with the fundamental combination of electric fields. We describe beam combination techniques and how they are realized at the observatories used in the conduct of this research. We subsequently give a mathematical description of the Keck Interferometer Nuller and describe our pathfinder effort to produce the first science with this instrument. We present the results of a 2.5 year observing campaign using four different observatories; the Spitzer Space Telescope, the Infrared and Optical Telescope Array on Mt. Hop- kins, Arizona, the Palomar Testbed Interferometer on Mt. Palomar, California, and the Keck Interferometer on Mauna Kea, Hawaii. We describe our observations of a broad array of low-mass binary stars and the recurrent nova RS Ophiuchi in outburst — a candidate Type Ia supernova progenitor. We present calculations that suggest a new paradigm for dust creation in recurrent novae. We explore this paradigm through analysis of line and continuum emission from near peak brightness to quiescence. We report radial velocity and astrometric model fitting on the low-mass M-dwarf binary Gliese 268. We derive masses of the constituent stars with 0.5% uncertainty. ii Dissertation Advisors Dr. William C. Danchi • Prof. Holland C. Ford • Dissertation Defense Committee Prof. Charles L. Bennett • Dr. William C. Danchi • Prof. Holland C. Ford • Dr. Matthew A. Greenhouse • Prof. Colin A. Norman • iii Acknowledgements I am grateful to Dr. William C. Danchi, Senior Astrophysicist in the Exoplanets and Stellar Astrophysics Laboratory of NASA/GSFC for his direct patronage and to Holland C. Ford, Professor of Physics and Astronomy at The Johns Hopkins Uni- versity and PI of the Hubble Space Telescope, Advanced Camera for Surveys for his guidance in my scientific research. I am further indebted to Dr. Damien S´egransen, Dr. Didier Queloz, and Brice-Oliver Demory of Observatoire de Gen`eve, Switzerland for their advice and collaboration in reduction of IOTA and ELODIE data and fitting of binary orbits and to Dr. Guillermo Torres of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA for his patient tutelage regarding binary stars and stellar astrophysics. I am also grateful to Professor Augustin Skopal of the Astronom- ical Institute, Slovak Academy of Sciences for his help and collegial encouragement as I struggled to learn about the physics of continuum emission in novae. I would like to thank Dr. Wesley Traub, Chief Scientist of the Navigator Program at NASA’s Jet Propulsion Laboratory and Project Scientist for the Terrestrial Planet Finder Coron- agraph, who helped me to formulate my thesis and made it possible for me to obtain iv the first science data from the Keck Interferometer Nuller. His general benevolence helped me survive some pretty rough spots, too. I am grateful to Mr. Gerald L. Van Deusen, my high school biology teacher. His love of science and deep respect for nature had a very strong influence on me early in my life. I would also like to thank Dr. Marc Lacasse for his help with instrument engineering issues on Mt. Hopkins and Dr. Ben Lane of the Massachusetts Institute of Technology and Prof. John Monnier of the University of Michigan for their help and guidance in the analysis of early data on the nova RS Ophiuchi. I would like to thank Charles Bennett, Professor of Physics and Astronomy at The Johns Hopkins University and PI of the Microwave Anisotropy Probe, Dr. Matthew Greenhouse, deputy project scientist for the James Webb Space Telescope at NASA/GSFC and Dr. John C. Mather, PI of the Cosmic Background Explorer/FIRAS and senior project scientist for JWST for their early encouragement of my thoughts of going back to graduate school in astrophysics and to Dr. William R. Oegerle, Director of the Astrophysics Science Division, NASA/GSFC for our many productive talks. I would like to thank the many scientists, engineers and technicians who designed, built and maintained the several observatories that I used to get the data I needed for this research. I have personally experienced many of these jobs and I know how terribly difficult it can be! With the greatest possible humility I would like to extend my very real gratitude to these colleagues - many of whom are unknown to me - for their countless hours of hard, quite often thankless, work. v I want to thank — no! to praise! — my family for their steadfast support. They were always there for me and helped me to face the many grim months I spent on the mountain struggling to obtain my thesis data. That was awfully hard for all of us, but we survived! ———————————————————————– Lastly, and most importantly, I want to thank my kids; Madeleine, whose love of life is a very real inspiration, and Finnian, who tried to be good. vi For Rebecca vii Contents Abstract ii Acknowledgements iv List of Tables xi List of Figures xii 1 Introduction 1 2 The Technique of Long-baseline Stellar Interferometry 11 2.1 Young’sExperiment ........................... 12 2.2 BeamCombination ............................ 14 2.2.1 AMathematicalIntroduction . 14 2.2.2 Visibility.............................. 20 2.2.3 BeamCombinationMethods. 23 2.2.4 Multiple Baselines and Closure Phase . 26 2.3 InterferometricObservatories . .. 28 2.3.1 The Infrared and Optical Telescope Array . 28 2.3.2 The Palomar Testbed Interferometer . 32 2.3.3 The Keck Interferometer Nuller . 33 2.4 Mathematical Nulling Interferometry . ... 38 3 The Recurrent Nova RS Ophiuchi 42 3.1 TaxonomyRSOph ............................ 43 3.2 Interferometric Observations of RS Oph -Epoch1 ................................. 47 3.2.1 Observations ........................... 49 3.2.2 Analysis .............................. 52 3.2.3 Discussion............................. 55 viii 3.3 Interferometric Observations of RS Oph -Epoch2 ................................. 57 3.3.1 Observations ........................... 58 3.3.2 Analysis .............................. 60 3.3.3 Discussion............................. 64 3.4 OntheDistancetoRSOph ....................... 73 3.4.1 TheHistoricalRecord . 74 3.4.2 Epoch2006 ............................ 82 3.4.3 Outstanding Issues and a Distance Estimate . 88 3.4.4 Suggested Observations to Resolve the Distance Issue ..... 92 3.5 Conclusion................................. 93 4 Observations of RS Oph with the Keck Interferometer Nuller 96 4.1 The Keck Interferometer Nuller . 98 4.2 Observations................................ 101 4.3 DataandAnalysis ............................ 105 4.4 A New Physical Model of the Recurrent Nova . 123 4.4.1 LuminosityEvolution. 133 4.5 Supporting Evidence for the Proposed Dust Creation Paradigm . 140 4.5.1 Spitzer Observations ....................... 141 4.5.2 Discussion of Spitzer Observations . 143 5 The Continuum of RS Oph 151 5.1 SymbioticStellarSystems . 152 5.2 The Continua of Symbiotic Stellar Systems . ... 157 5.2.1 Methodology for Analysis of Continua . 158 5.3 AnalysisoftheContinuumofRSOph . 170 5.3.1 FittingtheSED.......................... 172 5.3.2 OntheDetectionofDust . 181 5.3.3 Implications for the KIN Outer Spatial Regime Data . 187 5.3.4 Evolution of the Spectral Energy Distribution . ... 189 5.3.5 Summary of the Continuum Analysis . 194 6 Stellar Masses from Spectroscopy and Interferometry 195 6.1 The Importance of Stellar Mass andLuminosity .............................. 196 6.2 Scientifically Interesting Binary Stars . ..... 199 6.3 TheAstrometricObservingProgram . 203 6.4 AnApproachtoDeterminationofMass. 204 6.5 A Brief Review of Radial Velocity Orbits . 207 6.6 Measurement Error and Derived StellarParameters ............................ 213 ix 6.6.1 LineBlending ........................... 214 6.6.2 Starspots ............................. 215 6.7 TheM-dwarfbinaryGliese268 . 217 6.7.1 Orbitalsolution. .. .. 226 6.7.2 ModelTesting........................... 230 6.7.3 Conclusion............................. 232 Bibliography 233 Vita 253 x List of Tables 3.1 Epoch 1 interferometer observing log for RS Oph . ... 49 3.2 Epoch1modelfitparametersforRSOph . 53 3.3 Epoch 2 interferometer observing log for RS Oph . ... 59 3.4 Epoch 2 elliptical gaussian model fits . .. 61 3.5 Distance determinations for the recurrent nova RS Oph . ...... 87 4.1 KINobservinglogforRSOph. 102 4.2 RSOphmodelfittingresults. 107 4.3 Mid-infrared Spitzer linelist:N-band. 113 4.4 Continuum-normalized KIN emission source identification....... 114 4.5 Post-outburst evolution of the white dwarf star in RS Oph ...... 134 6.1 Programstars............................... 205 6.2 OrbitalandbinaryelementsofGL268 . 228 6.3 Physical parameters of the GL268 system and individual components 229 xi List of Figures 2.1 ThomasYoung’sexperiment . 13 2.2 Schematic representation of an interferometer . ...... 15 2.3 Corrugated interferometer acceptance pattern . ...... 18 2.4 Polychromaticfringecoherence . 19 2.5 UVcoverageofKeckInterferometer . 20 2.6 Sample visibilities using the Keck Interferometer . ........ 21 2.7 Beamcombinationmethods . 23 2.8 Fiberbeamcombination . .. .. 25 2.9 Closurephase ............................... 27 2.10IOTAObservatory ............................ 29