Double Trouble: The Impact of Binarity on Large Stellar Rotation Datasets DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Gregory Vahag Aghabekian Simonian Graduate Program in Astronomy The Ohio State University 2019 Dissertation Committee: Professor Marc Pinsonneault, Advisor Professor Donald Terndrup Professor Todd Thompson Copyright by Gregory Vahag Aghabekian Simonian 2019 Abstract The Kepler satellite revolutionized our understanding of stellar rotation by providing tens of thousands of rotation periods for stars in the Kepler field, including a substantial fraction of rapid rotators. I explore the nature of the rapid rotators there both using Gaia parallazes and spectra from APOGEE. One expected source of rapid rotators in the Kepler field is a population of tidally-synchronized binaries. I test the binary nature of the Kepler rapid rotators using Gaia parallaxes to distinguish photometric binaries (PBs) from single stars on the unevolved lower main sequence, and compare their distribution of rotation properties to those of single stars both with and without APOGEE spectroscopic characterization. I find that 59% of stars with 1:5 day < P < 7 day lie 0.3 mag above the main sequence, compared with 28% of the full rotation sample. The fraction of stars in the same period range is 1:7 ± 0:1% of the total sample analyzed for rotation periods. Both the photometric binary fraction and the fraction of rapid rotators are consistent with a population of non-eclipsing short period binaries inferred from Kepler eclipsing binary data after correcting for inclination. This suggests that the rapid rotators are dominated by tidally-synchronized binaries rather than single-stars obeying traditional angular momentum evolution. This finding provokes ii caution against interpreting rapid rotation in the Kepler field as a signature of youth. Following up this new sample of 217 candidate tidally-synchronized binaries will help further understand tidal processes in stars. I also use the 5466 spectroscopic v sin i measurements of Kepler dwarfs and subgiants from the APOGEE survey to explore stellar rotation in late-type dwarfs. I find a detection threshold of 10 km/s, which also allows me to explore the spindown of intermediate-mass stars leaving the main sequence, merger products, young stars, and tidally-synchronized binaries. I use Gaia parallaxes and APOGEE temperatures to calculate radii and to search for photometric binaries. For the unevolved lower main sequence, I see the same concentration toward rapid rotation in photometric binaries as that observed in rotation period data, but at an enhanced rate. I attribute this difference to unresolved spectroscopic binaries with velocity displacements on the order of the APOGEE resolution, which can spuriously overestimate rotational broadening. Among cool, unevolved stars where rapid single star rotation is not expected, I find an excess detection rate of 4 ± 1%, which I argue is a measure of the impact of this phenomenon. For the subgiants, I use asteroseismic data to demonstrate that period and v sin i methods agree, indicating the v sin i measurements are less impacted by the presence of binaries for these targets. There is clear evidence for a transition between rapid and slow rotation on the subgiant branch in the domain predicted by modern angular momentum evolution models, with detections on the hot side much larger than the background iii from binary stars. I also find substantial agreement between the spectroscopic and photometric properties of KIC targets added by Huber et al. (2014) based on 2MASS photometry. iv Dedication To Armin´efor supporting me on my journey to make this dream come true v Acknowledgments I wish to thank my advisor, Marc Pinsonneault, for his unflinching support and advocacy in getting me through my dissertation. I also thank my committee, Don Terndrup and Todd Thompson, for their scientific as well as emotional support and for continually reminding me that this work itself is a contribution to scientific knowledge. I also acknowledge emotional support from the other faculty at OSU, especially Paul Martini, who advised my first-year project leading to a publication, and Kris Stanek who showed me the value of having a side-project to work on when I hit a wall with my main project. I also thank my family, both in California and in Ohio, for always cheering me on and encouraging me to follow my dream. My mother and father, Alice and Matzak, as well as my mother-in-law and father-in-law, Kevork and Svetlana. I'm also extremely grateful for the advise and support of my siblings and their spouses, Vicken and Cristina as well as Tatevik and Mitch, who have always had an open ear. Thanks as well to my niece little Viona, who can always brighten up a heavy day. Thanks to all of you, I made it! vi This dissertation also wouldn't have been possible without the graduate students, especially Jamie Tayar and Stacy Kim, in the OSU Astronomy Department always willing to have interesting conversations to break from research. I also have drawn support from fellow officers of the Armenian Student Association, especially Tatevik Broutian and Mary Sagatelova, who made the graduate school experience more enjoyable. The support I've had at OSU has been a privilege. The research behind this work also benefitted from the financial support of the undergraduates at The Ohio State University, NASA ADP Grant NNX15AF13G and from the National Science Foundation via grant AST-1411685 to The Ohio State University. Last, but certainly not least, this dissertation would have been substantially more difficult without the support of my wife, Armin´eEmma Aghabekian Simonian. Our hard work has paid off! vii Vita August 3, 1991 . Born { Los Angeles, CA 2013 . B.S. Astrophysics, California Institute of Technology 2013 { 2019 . Graduate Teaching and Research Associate, The Ohio State University Publications Research Publications 1. S.J. Schmidt . and G.V.A. Simonian \The Largest M Dwarf Flares from ASAS-SN", ApJ, 876, 115, (2019). 2. D.S. Aguado, . , G. Simonian, . \The Fifteenth Data Release of the Sloan Digital Sky Surveys: First Release of MaNGA-derived Quantities, Data Visualization Tools, and Stellar Library", ApJS, 240, 23, (2019). 3. G.V.A. Simonian, M.H. Pinsonneault, D.M. Terndrup \Rapid Rotation in the Kepler Field: Not a Single Star Phenomenon", ApJ, 871, 174, (2019). 4. G. De Rosa, . , G.V. Simonian, . \Velocity-resolved Reverberation Mapping of Five Bright Seyfert 1 Galaxies", ApJ, 866, 133, (2018). 5. M.M. Fausnaugh, . , G.V. Simonian, . \Continuum Reverberation Mapping of the Accretion Disks in Two Seyfert 1 Galaxies", ApJ, 854, 107, (2018). 6. S.J. Swihart, . , G.V. Simonian, . \2FGL J0846.0+2820: A New Neu- tron Star Binary with a Giant Secondary and Variable γ-Ray Emission", ApJ, 851, viii 31, (2017). 7. S. Mathur, . , G.V. Simonian, . \Space Telescope and Optical Rever- beration Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy", ApJ, 846, 55, (2017). 8. T.W.S. Holoien, . , G.V. Simonian, . \The ASAS-SN bright supernova catalogue - II. 2015", MNRAS, 467, 1098, (2017). 9. M.M. Fausnaugh, . , G.V. Simonian, . \Reverberation Mapping of Op- tical Emission Lines in Five Active Galaxies", ApJ, 840, 97, (2017). 10. L. Pei, . , G.V. Simonian, . \Space Telescope and Optical Reverbera- tion Mapping Project. V. Optical Spectroscopic Campaign and Emission-line Analysis for NGC 5548", ApJ, 837, 131, (2017). 11. G.V. Simonian and P. Martini \Circumstellar dust, PAHs and stellar populations in early-type galaxies: insights from GALEX and WISE", MNRAS, 464, 3920, (2017). 12. T.W.S. Holoien, . , G.V. Simonian, . \ The ASAS-SN bright super- nova catalogue - I. 2013-2014", MNRAS, 464, 2672, (2017). 13. B.J. Shappee, . , G.V. Simonian, . \The Young and Bright Type Ia Supernova ASASSN-14lp: Discovery, Early-time Observations, First-light Time, Distance to NGC 4666, and Progenitor Constraints", ApJ, 826, 144, (2016). 14. S. Dong, . , G.V. Simonian, . \ASASSN-15lh: A highly super-luminous supernova" Science, 351, 257, (2016). 15. T.W.S. Holoien, . , G.V. Simonian, . \Six months of multiwavelength follow-up of the tidal disruption candidate ASASSN-14li and implied TDE rates from ASAS-SN", MNRAS, 455, 2918, (2016). 16. A. Pastorello, . , G.V. Simonian, . \Massive stars exploding in a He- rich circumstellar medium - VII. The metamorphosis of ASASSN-15ed from a narrow line Type Ibn to a normal Type Ib Supernova", MNRAS, 453, 3649, (2015). 17. H.C. Campbell, . , G. Simonian, . \Total eclipse of the heart: the AM CVn Gaia14aae/ASSASN-14cn", MNRAS, 452, 1060, (2015). 18. D. Levitan, . , G.V. Simonian, . \Five new outbursting AM CVn sys- ix tems discovered by the Palomar Transient Factory", MNRAS, 430, 996, (2013). Fields of Study Major Field: Astronomy x Table of Contents Abstract ......................................... ii Dedication ........................................ v Acknowledgments ................................... vi Vita ............................................. viii List of Tables ...................................... xiv List of Figures ...................................... xv Chapter 1: Introduction ............................... 1 1.1 Kepler Rotation Periods . 3 1.2 Spectroscopic v sin i ............................ 5 Chapter 2: The Kepler Rotation Periods ................... 8 2.1 Catalog Data . 8 2.1.1 Default Stellar Parameters . 9 2.1.2 Astrometric Data . 9 2.1.3 Photometric Data . 10 2.1.4 Rotation Data . 11 2.1.5 Spectroscopic Parameters . 12 xi 2.1.6 Eclipsing Binaries . 14 2.2 Data Analysis . 15 2.2.1 Stellar Model . 16 2.2.2 Isolating Unevolved Stars . 16 2.2.3 Metallicity Distribution . 18 2.2.4 Correcting Metallicity Trends . 19 2.2.5 Temperature Corrections . 20 2.2.6 The Impact of Metallicity on the Main Sequence Width . 21 2.2.7 Characterizing the EB Distribution . 22 2.2.8 Binarity and Temperature Estimation . 24 2.3 Results and Discussion .