Compilation of Nearby Brown Dwarfs and Ultracool Stars
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Mississippi State University Scholars Junction Theses and Dissertations Theses and Dissertations 1-1-2012 The Hinterland: Compilation of Nearby Brown Dwarfs and Ultracool stars Christopher David Ramos Follow this and additional works at: https://scholarsjunction.msstate.edu/td Recommended Citation Ramos, Christopher David, "The Hinterland: Compilation of Nearby Brown Dwarfs and Ultracool stars" (2012). Theses and Dissertations. 4481. https://scholarsjunction.msstate.edu/td/4481 This Graduate Thesis - Open Access is brought to you for free and open access by the Theses and Dissertations at Scholars Junction. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of Scholars Junction. For more information, please contact [email protected]. The hinterland: compilation of nearby brown dwarfs and ultracool stars By Christopher David Ramos A Thesis Submitted to the Faculty of Mississippi State University in Partial Fulfillment of the Requirements for the Degree of Master of Science in Physics in the Department of Physics and Astronomy Mississippi State, Mississippi December 2012 Copyright by Christopher David Ramos 2012 The hinterland: compilation of nearby brown dwarfs and ultracool stars By Christopher David Ramos Approved: Angelle M. Tanner David L. Monts Assistant Professor of Professor and Graduate Coordinator of Physics and Astronomy Physics and Astronomy (Director of Thesis) (Committee Member) Wenchao Ma R. Gregory Dunaway Professor of Professor and Interim Dean Physics and Astronomy College of Arts & Sciences (Committee Member) Name: Christopher David Ramos Date of Degree: December 15, 2012 Institution: Mississippi State University Major Field: Physics Major Professor: Dr. Angelle M. Tanner Title of Study: The hinterland: compilation of nearby brown dwarfs and ultracool stars Pages of Study: 122 Candidate for Degree of Master of Science This work is a compilation and analysis of ultracool dwarfs (UCDs) and brown dwarfs within 25 parsecs. It supplements the work of Stauffer et al. [2010] who updated the reputable and widely relied upon Third Catalog of Nearby Stars [Gliese & Jahreiß 1991] with revised coordinates and cross-matched each object with the 2MASS point source catalog [Cutri et al. 2003]. I began by incorporating newly discovered (post 1991) cool companions to Gliese-Jahreiß stars that had been previously undetectable. I then expanded the compilation to include isolated UCDs and other nearby systems with at least one UCD component. Multiple systems are a panacea for astrophysical problems: by applying Kepler’s laws, the model-independent mass of brown dwarfs and low mass stars can be determined and hence serve to constrain theory. This work puts this data into context by exploring the history of brown dwarf theory and reviewing open questions concerning their nature. Key words: brown dwarfs, binaries, low-mass, stars, thesis DEDICATION A world full of fear and despair cries out for the uplifting light of knowledge. To hold up the torch, burn away the ignorance, and reach down with an empathetic hand is the obligation of the learned` natural philosopher. One is a bridge for the many; the many the support of one. I’ll always reach for the stars; but no matter how far I get, I’ll never forget where I came from and who I left. I dedicate this thesis to my family and friends. While science and reason guide me, my love for them is what drives me. ii ACKNOWLEDGEMENTS This research has made use of the SIMBAD and VizieR services, operated at CDS, Strasbourg, France. This research has made use of NASA’s Astrophysics Data System. This research has made use of the resources provided at dwarfarchives.org. This research has made use of the Washington Double Star Catalog maintained at the U.S. Naval Ob- servatory; and this publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This work also makes use of data provided by the Research Consortium on Nearby Stars; thank you Dr. Henry and Dr. Riedel. iii TABLE OF CONTENTS DEDICATION . ii ACKNOWLEDGEMENTS . iii LIST OF TABLES . vi LIST OF FIGURES . .x NOMENCLATURE . xi CHAPTER 1. THE NATURE OF BROWN DWARFS: AN OVERVIEW . .1 1.1 What is a brown dwarf? – a provisional definition . .1 1.2 Motivation . .2 1.3 Discovery! . .4 1.4 Evolution . .5 1.5 Formation . 10 2. THE PROJECT . 17 2.1 Gliese, Jahreiß, and Woolley revisited . 17 2.2 Ultracool Companions to GJ and Other Nearby Stars . 18 3. THE DWARFS . 82 3.1 Methodology . 82 3.2 Statistics and Comparisons . 85 4. CONCLUSIONS . 93 REFERENCES . 94 iv APPENDIX A. NOTABLE OBJECTS . 108 A.1 GD 165 B (1988) . 109 A.2 ISO-Oph 102 (1992) . 109 A.3 GJ 229 B (1995) . 110 A.4 PPL 15 and Teide 1 (1996) . 110 A.5 Kelu-1 AB (1997) . 110 A.6 GJ 4052 C (2001) . 110 A.7 GJ 845 BaBb (2003) . 111 A.8 GJ 164 B (2004) . 111 A.9 GJ 9492 B (2004) . 112 A.10 SCR 1845-6357 B (2006) . 112 A.11 GJ 758 B (2009) . 112 A.12 UGPS J072227.51-054031.2 (2010) & WISEP J173835.52+273258.9 (2011) . 112 A.13 GJ 240.1 B (2011) . 113 A.14 GJ 3483 B (2011) . 113 A.15 Oph B-11 (2012) . 113 B. DISCREPENCIES . 115 B.1 Simbad . 116 B.2 Confounded Designations . 117 C. PROFILE QUESTIONS . 119 v LIST OF TABLES 2.1 Objects Comprising Nearby Ultracool Systems . 21 2.2 Photometry . 37 2.3 Objects Comprising Gliese-Jahreiß Ultracool Systems . 54 2.4 Objects Comprising Nearby non Gliese-Jahreiß Ultracool Systems . 59 2.5 Component Masses and Orbital Elements of Nearby Ultracool Systems . 71 2.6 Statistics . 81 3.1 The Hierarchical Quintuple System GJ 643/644 . 87 3.2 The Hierarchical Triple System GJ 564 . 87 3.3 Quick Ultracool Dwarf Separations Statistics . 88 vi LIST OF FIGURES 3.1 GJ 643/644 Tree Diagram . 88 3.2 The Spectral Class Distribution of Ultracool Dwarfs: M6–Y2 . 89 3.3 The Separation Distribution of Ultracool Dwarf Binaries . 90 3.4 The Mass-Ratio Distribution of Ultracool Dwarf Binaries . 91 3.5 Scatter Plot of Ultracool Dwarf Binaries . 92 vii NOMENCLATURE a semimajor axis AU the astronomical unit, the ostensible separation between the Earth and the Sun, defined as 149,597,870,700 m B class star with a surface temperature ranging from 10,000 to 31,500 K, identified by neutral helium and strong hydrogen brown dwarf a stellar object unable to sustain core fusion of hydrogen, yet able to fuse deuterium celestial sphere the projection of earth’s latitude and longitude system onto the sky CNS3 the Third Catalog of Nearby Stars DBML the Deuterium Burning Mass Limit, mass threshold for the fusion of deuterium; epoch 2000 refers to coordinates in terms of year 2000 equatorial positions on the celestial sphere GJ Gliese-Jahreiß, catalog acronym for objects in the CNS3 HBML the Hydrogen Burning Mass Limit, mass threshold for the fusion of hydrogen HIRES high resolution echelle spectrometer, instrument of the Keck observatory in Hawaii J2000 an equinox of J2000 refers to an equatorial coordinate system defined by the Earth’s orientation in year 2000 JHKs a set of infrared photometry filter standards, centered on 1.2, 1.6, and 2.2 µm, respec- tively L dwarf with a surface temperature ranging from about 1,300 to 2,200 K, identified by absence of hydrogen and presence of metallic hydrides, alkali metals viii M dwarf with a surface temperature ranging from about 2,200 to 4,000 K, identified by neutral metals and little sign of hydrogen mas milliarcsecond metallicity the proportion of a star made up of elements other than hydrogen and helium M> Earth Mass MJup Jupiter Mass M⊙ Solar Mass Myr megayear, or 1,000,000 years O class star with a surface temperature ranging from about 31,500 to 49,000 K, identified by ionized and neutral helium, weak hydrogen parallax the apparent displacement, in arcseconds, of a star in the sky due to the perpendicular change in position of an Earthbound observer by 1 AU Population I and II stars that are young and metal rich and stars that are old and metal poor, respectively pc parsec, the distance corresponding to a parallax angle of 1,000 mas and approximately equivalent to 3.26 light-years q the stellar mass ratio of secondary to primary QSO quasi-stellar object, very distant and very energetic electromagnetic sources embedded in the cores of young galaxies solar star a star with a spectral falling between F6 and K3 T dwarf with a surface temperature ranging from about 700 to 1,300 K, identified by methane llines UCD ultracool dwarf, a dwarf star with a spectral type later or equal to M6 VLM very low mass, M ≲ 0.1 M . ix V visual photometry standard, Johnson V is centered on 544.8 nm, with a FWHM of 84 nm Y dwarf with a temperature less than about 700 K, identified by ammonia lines x CHAPTER 1 THE NATURE OF BROWN DWARFS: AN OVERVIEW 1.1 What is a brown dwarf? – a provisional definition Brown dwarfs are often described as “failed stars” because, while composed predom- inantly of hydrogen, they lack the mass to sustain core fusion of hydrogen. Shiv Kumar [1963b] originally denoted these objects “black dwarfs” as it was predicted that their low mass would cause them to contract into degenerate objects soon1 after formation; however, the astronomy community decided upon “brown dwarf”2 with the coining of the term by Jill Tarter [1975].