DOCSLIB.ORG

Nofi Hawii 0085A 10821.Pdf

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Nofi Hawii 0085A 10821.Pdf A SEARCH FOR SUBSTELLAR COMPANIONS AROUND PRE-MAIN SEQUENCE STARS USING INFRARED SPECTROSCOPY A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI`I AT MANOA¯ IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN ASTRONOMY September 2020 By Larissa A. Nofi Dissertation Committee: Daniel Huber, Chairperson Klaus Hodapp Andrew Howard Paul Lucey Karen Meech John Rayner c Copyright 2020 by Larissa A. Nofi All Rights Reserved ii This dissertation is dedicated to all those who had confidence in my abilities. Thank you for the support. iii Acknowledgements First and foremost, I would like to acknowledge the mentors and colleagues who supported this work. I am grateful to my advisor, Dan Huber, and my committee for valuable insights and guidance. I wish to express my thanks to the IGRINS team and other collaborators from multiple institutions, all of whom contributed meaningfully to this dissertation. Thank you to my fellow graduate students for your friendship and support, and particularly to Kelly Blumenthal, for being a constant presence and source of motivation. I am so grateful we were able to share every step of this process together. I would also like to acknowledge the efforts of the Lowell Discovery Telescope staff and the use of the Immersion Grating Infrared Spectrometer (IGRINS), developed by a collaboration between University of Texas at Austin and the Korea Astronomy and Space Science Institute (KASI). I acknowledge the gracious support of the Lowell Pre-doctoral Fellowship by the BF Foundation, funding provided by the Visiting Astronomer at the Infrared Telescope Facility program, which is operated by the University of Hawaii under contract 80HGTR19D0030 with the National Aeronautics and Space Administration, and the Institute for Astronomy and University of Hawaii for supporting a graduate scholarship. I am grateful to my long-time mentor, Sloane Wiktorowicz, for consistently inspiring and challenging me, and for being a model of a scientist I wished to become. Thank you to colleagues at Lick Observatory and UC Santa Cruz who encouraged me in my education prior to graduate school, and to the professors at City College of San Francisco who saw potential in me before I was able to see it in myself. This accomplishment belongs to all of you. iv I would particularly like to acknowledge and thank my husband, who never wavered in his support, and who has now moved across an ocean three times with me so that I could make this ambition a reality. v Abstract Observing and characterizing newly-formed planets around young stars is important for developing planet formation and evolution theory. However, given the challenges involved in detecting young planetary systems, current models are primarily based on observed systems that are billions of years old. In this dissertation, I present a survey to characterize pre-main sequence stars, and detect or confirm young substellar companions using the radial velocity (RV) method. This survey used the Immersion Grating Infrared Spectrograph (IGRINS), which was deployed as a visiting instrument at the 4.3-m Lowell Discovery Telescope (LDT). Infrared spectroscopy is preferable to optical because it is less affected by RV variability triggered by stellar activity effects, such as starspots. The initial survey consisted of 70 pre-main sequence stars with ages <5 Myr in the relatively nearby Taurus star-forming region. I measured the projected rotational velocity (v sin i) of these pre-main sequence stars, and related the rotation (and other properties) to young star evolution. Additionally, I investigated a subset of 10 targets to look for substellar companions. The RV survey is generally sensitive to hot Jupiters with mass >6 MJ and brown dwarfs within ∼1 AU. No companions were detected in this sample, however, upper limits on occurrence rates were estimated based on injection/recovery simulations, and are consistent with multiple theories of formation and evolution. Correlations between stellar properties and RV scatter indicate that rotation, stellar activity, and disk accretion are possible contributing factors to RV variability. The average infrared RV scatter is roughly half the typical optical RV scatter for very young stars, confirming the potential of infrared RV surveys to detect young substellar companions. vi Table of Contents Acknowledgements . iv Abstract . vi List of Tables . ix List of Figures . x Chapter 1: Introduction . 1 1.1 Motivation . 1 1.2 Exoplanet Detection Techniques . 5 1.2.1 Direct Imaging Method . 5 1.2.2 Transit Method . 6 1.2.3 Radial Velocity Method . 8 1.3 Substellar Companions Around Young Stars . 12 1.3.1 Formation and Evolution Theory . 12 1.3.2 Occurrence Rates of Substellar Companions . 24 1.3.3 Young Substellar Candidate Discoveries . 29 1.4 Science Objectives . 33 Chapter 2: Survey Overview . 49 2.1 Sample Selection . 49 2.2 Infrared Spectroscopy Survey . 56 2.2.1 Finding Young Substellar Companions: Challenges and Solutions . 56 2.2.2 Observations and Data Reduction . 62 vii 2.3 Prior Optical Spectroscopy Survey . 67 2.4 Optical Photometric Survey . 73 Chapter 3: Stellar Properties of Pre-Main Sequence Stars . 84 3.1 Introduction . 85 3.2 Analysis . 87 3.2.1 Stellar Effective Temperatures . 87 3.2.2 Infrared v sin i .............................. 88 3.2.3 Optical v sin i .............................. 95 3.2.4 Stellar Rotation Periods . 97 3.2.5 Stellar Radius Limits . 98 3.3 Discussion . 98 3.3.1 Distributions of Stellar Parameters . 98 3.3.2 Effects of Multiplicity on v sin i . 100 3.3.3 Comparison of Optical and Infrared v sin i . 103 3.3.4 Correlation of v sin i and Evolutionary States . 109 3.4 Conclusions . 115 Chapter 4: A Search for Substellar Companions around Pre-Main Sequence Stars . 128 4.1 Methodology . 129 4.1.1 Forward Modeling Technique . 129 4.1.2 RV Measurements . 131 4.1.3 RV Precision . 142 4.1.4 Periodogram Analysis . 148 4.1.5 Sources of Spurious RV Signals . 153 4.1.6 Detection Limits from Injection and Recovery Tests . 158 4.2 Results and Discussion . 160 4.2.1 Individual System Results . 160 4.2.2 Discussion . 196 Chapter 5: Conclusions and Summary . 228 viii Appendix: Radial Velocities of Pre-Main Sequence Stars and the RV Standard Star 236 ix List of Tables 2.1 Sample of 70 Pre-Main Sequence Stars . 53 2.2 IGRINS Specifications . 63 2.3 Observations Summary . 65 3.1 K-S and A-D Test Results . 100 3.2 Stellar Properties of Pre-Main Sequence Stars . 117 4.1 RV Target Properties and Observations . 163 4.2 Completeness of Individual RV Target Datasets . 204 4.3 Infrared RV Scatter . 212 A.1 GJ 281 RVs . 236 A.2 CI Tau RVs . 239 A.3 V830 Tau RVs . 242 A.4 DK Tau RVs . 246 A.5 V1075 Tau RVs . 249 A.6 AA Tau RVs . 253 A.7 DM Tau RVs . 255 A.8 GI Tau RVs . 256 A.9 GM Tau RVs . 257 A.10 IQ Tau RVs . 258 A.11 LkCa 15 RVs . 260 x List of Figures 1.1 The Brown Dwarf Desert . 4 1.2 Example of Direct Imaging Detection . 6 1.3 Example Transit Detection . 7 1.4 Example RV Detection . 9 1.5 Comparison of Orbital Eccentricity for Hot and Warm Jupiters . 19 1.6 Formation Scenarios for Hot and Warm Jupiters . 21 1.7 Occurrence Rates of Hot and Warm Jupiters . 28 2.1 K band Magnitudes of the 70 Pre-main Sequence Stars in the Sample . 51 2.2 Color-Magnitude Diagram of Sample . 57 2.3 Hertzsprung-Russell Diagram of Sample . 58 2.4 Diagram Illustrating How Starspots Cause RV Variability . 59 2.5 RVs Measured in Optical and Infrared Wavelengths . 61 2.6 IGRINS Echellogram . 64 2.7 IGRINS Echellograms Before and After Wavelength Calibration and Distortion Correction. 66 2.8 IGRINS Example Spectra . 68 2.9 Example of Line Bisector Analysis . 70 2.10 Detection of a Young Hot Jupiter Candidate, CI Tau b . 72 2.11 Example Lightcurve . 75 3.1 Example Spectra with Various v sin i Estimates . 89 xi 3.2 Relations Between the FWHM of the CCF and v sin i . 91 3.3 Comparison of v sin i Measurements Using Two Different Methods . 94 3.4 Comparison of Stellar Properties . 99 3.5 The v sin i Distribution of Single and Multiple System Pre-Main Sequence Stars . 102 3.6 Comparison of Optical and Infrared v sin i Measurements . 105 3.7 Comparison of Infrared and Literature v sin i Measurements . 108 3.8 Comparison of Infrared and Literature v sin i Measurements Based on Stellar Classification . 109 3.9 The v sin i Distributions for CTTSs and WTTSs . ..
Load more

Recommended publications
  • Curriculum Vitae - 24 March 2020
    Dr. Eric E. Mamajek Curriculum Vitae - 24 March 2020 Jet Propulsion Laboratory Phone: (818) 354-2153 4800 Oak Grove Drive FAX: (818) 393-4950 MS 321-162 [email protected] Pasadena, CA 91109-8099 https://science.jpl.nasa.gov/people/Mamajek/ Positions 2020- Discipline Program Manager - Exoplanets, Astro. & Physics Directorate, JPL/Caltech 2016- Deputy Program Chief Scientist, NASA Exoplanet Exploration Program, JPL/Caltech 2017- Professor of Physics & Astronomy (Research), University of Rochester 2016-2017 Visiting Professor, Physics & Astronomy, University of Rochester 2016 Professor, Physics & Astronomy, University of Rochester 2013-2016 Associate Professor, Physics & Astronomy, University of Rochester 2011-2012 Associate Astronomer, NOAO, Cerro Tololo Inter-American Observatory 2008-2013 Assistant Professor, Physics & Astronomy, University of Rochester (on leave 2011-2012) 2004-2008 Clay Postdoctoral Fellow, Harvard-Smithsonian Center for Astrophysics 2000-2004 Graduate Research Assistant, University of Arizona, Astronomy 1999-2000 Graduate Teaching Assistant, University of Arizona, Astronomy 1998-1999 J. William Fulbright Fellow, Australia, ADFA/UNSW School of Physics Languages English (native), Spanish (advanced) Education 2004 Ph.D. The University of Arizona, Astronomy 2001 M.S. The University of Arizona, Astronomy 2000 M.Sc. The University of New South Wales, ADFA, Physics 1998 B.S. The Pennsylvania State University, Astronomy & Astrophysics, Physics 1993 H.S. Bethel Park High School Research Interests Formation and Evolution
    [Show full text]
  • Open Research Online Oro.Open.Ac.Uk
    Open Research Online The Open University’s repository of research publications and other research outputs What are the hot R Coronae Borealis stars? Journal Item How to cite: De Marco, Orsola; Clayton, Geoffrey C.; Herwig, F.; Pollacco, D. L.; Clark, J. S. and Kilkenny, David (2002). What are the hot R Coronae Borealis stars? Astronomical Journal, 123(6) pp. 3387–3408. For guidance on citations see FAQs. c 2002 The American Astronomical Society Version: [not recorded] Link(s) to article on publisher’s website: http://dx.doi.org/doi:10.1086/340569 http://www.iop.org/EJ/abstract/1538-3881/123/6/3387 Copyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyright owners. For more information on Open Research Online’s data policy on reuse of materials please consult the policies page. oro.open.ac.uk The Astronomical Journal, 123:3370–3379, 2002 June # 2002. The American Astronomical Society. All rights reserved. Printed in U.S.A. EXTENDED NEAR-INFRARED EMISSION FROM CANDIDATE PROTOSTARS IN THE TAURUS-AURIGA MOLECULAR CLOUD Shinae Park Department of Physics, 366 Le Conte Hall, University of California, Berkeley, Berkeley, CA 94720-7300 and Scott J. Kenyon Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 Received 2001 December 17; accepted 2002 February 28 ABSTRACT We describe near-IR imaging data for a sample of 23 Class I sources in the Taurus-Auriga dark clouds. Combining our data with previous photometry, we detect brightness variations of 0.1–0.5 mag in many sources. The near-IR morphologies are consistent with millimeter continuum measurements.
    [Show full text]
  • The Rings and Inner Moons of Uranus and Neptune: Recent Advances and Open Questions
    Workshop on the Study of the Ice Giant Planets (2014) 2031.pdf THE RINGS AND INNER MOONS OF URANUS AND NEPTUNE: RECENT ADVANCES AND OPEN QUESTIONS. Mark R. Showalter1, 1SETI Institute (189 Bernardo Avenue, Mountain View, CA 94043, mshowal- [email protected]! ). The legacy of the Voyager mission still dominates patterns or “modes” seem to require ongoing perturba- our knowledge of the Uranus and Neptune ring-moon tions. It has long been hypothesized that numerous systems. That legacy includes the first clear images of small, unseen ring-moons are responsible, just as the nine narrow, dense Uranian rings and of the ring- Ophelia and Cordelia “shepherd” ring ε. However, arcs of Neptune. Voyager’s cameras also first revealed none of the missing moons were seen by Voyager, sug- eleven small, inner moons at Uranus and six at Nep- gesting that they must be quite small. Furthermore, the tune. The interplay between these rings and moons absence of moons in most of the gaps of Saturn’s rings, continues to raise fundamental dynamical questions; after a decade-long search by Cassini’s cameras, sug- each moon and each ring contributes a piece of the gests that confinement mechanisms other than shep- story of how these systems formed and evolved. herding might be viable. However, the details of these Nevertheless, Earth-based observations have pro- processes are unknown. vided and continue to provide invaluable new insights The outermost µ ring of Uranus shares its orbit into the behavior of these systems. Our most detailed with the tiny moon Mab. Keck and Hubble images knowledge of the rings’ geometry has come from spanning the visual and near-infrared reveal that this Earth-based stellar occultations; one fortuitous stellar ring is distinctly blue, unlike any other ring in the solar alignment revealed the moon Larissa well before Voy- system except one—Saturn’s E ring.
    [Show full text]
  • INAUGURAL – DISSERTATION Dipl.-Phys. Alexander A. Schegerer
    INAUGURAL – DISSERTATION zur Erlangung der Doktorwurde¨ der Naturwissenschaftlich-Mathematischen Gesamtfakult¨at der Ruprecht - Karls - Universit¨at Heidelberg vorgelegt von Dipl.-Phys. Alexander A. Schegerer, geboren in Kaufbeuren Tag der mundlichen¨ Prufung:¨ 17. Oktober 2007 II Struktur- und Staubentwicklung in zirkumstellaren Scheiben um T Tauri-Sterne Analyse und Modellierung hochaufl¨osender Beobachtungen in verschiedenen Wellenl¨angenbereichen Gutachter: Prof. Dr. Thomas Henning Prof. Dr. Wolfgang Duschl IV Meinen Eltern, Maria-Christa und Wolfgang Schegerer, gewidmet. VI Thema Im Zentrum dieser Doktorarbeit steht die Untersuchung der inneren Strukturen zirkumstella- rer Scheiben um T Tauri-Sterne sowie die Analyse zirkumstellarer Staub- und Eisteilchen und ihres Einflusses auf die Scheibenstruktur. Unter Zuhilfenahme von theoretisch berechneten Vergleichsspektren gibt der Verlauf der 10 µm-Emissionsbande in den Spektren junger stellarer Objekte Hinweise auf den Entwick- lungsgrad von Silikatstaub. Die Silikatbanden von 27 T Tauri-Objekten werden analysiert, um nach potentiell vorliegenden Korrelationen zwischen der Silikatstaubzusammensetzung und den stellaren Eigenschaften zu suchen. Analog erlaubt das Absorptionsband bei 3 µm, das dem Wassereis zugeschrieben wird, eine Untersuchung der Entwicklung von Eisk¨ornern in jungen stellaren Objekten. Erstmals ist es gelungen, kristallines Wassereis im Spektrum eines T Tauri-Objektes nachzuweisen. Unser wichtigstes Hilfsmittel zur Analyse der Temperatur- und Dichtestrukturen zirkum- stellarer
    [Show full text]
  • Abstracts of the 50Th DDA Meeting (Boulder, CO)
    Abstracts of the 50th DDA Meeting (Boulder, CO) American Astronomical Society June, 2019 100 — Dynamics on Asteroids break-up event around a Lagrange point. 100.01 — Simulations of a Synthetic Eurybates 100.02 — High-Fidelity Testing of Binary Asteroid Collisional Family Formation with Applications to 1999 KW4 Timothy Holt1; David Nesvorny2; Jonathan Horner1; Alex B. Davis1; Daniel Scheeres1 Rachel King1; Brad Carter1; Leigh Brookshaw1 1 Aerospace Engineering Sciences, University of Colorado Boulder 1 Centre for Astrophysics, University of Southern Queensland (Boulder, Colorado, United States) (Longmont, Colorado, United States) 2 Southwest Research Institute (Boulder, Connecticut, United The commonly accepted formation process for asym- States) metric binary asteroids is the spin up and eventual fission of rubble pile asteroids as proposed by Walsh, Of the six recognized collisional families in the Jo- Richardson and Michel (Walsh et al., Nature 2008) vian Trojan swarms, the Eurybates family is the and Scheeres (Scheeres, Icarus 2007). In this theory largest, with over 200 recognized members. Located a rubble pile asteroid is spun up by YORP until it around the Jovian L4 Lagrange point, librations of reaches a critical spin rate and experiences a mass the members make this family an interesting study shedding event forming a close, low-eccentricity in orbital dynamics. The Jovian Trojans are thought satellite. Further work by Jacobson and Scheeres to have been captured during an early period of in- used a planar, two-ellipsoid model to analyze the stability in the Solar system. The parent body of the evolutionary pathways of such a formation event family, 3548 Eurybates is one of the targets for the from the moment the bodies initially fission (Jacob- LUCY spacecraft, and our work will provide a dy- son and Scheeres, Icarus 2011).
    [Show full text]
  • The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST),
    A&A 468, 353–377 (2007) Astronomy DOI: 10.1051/0004-6361:20065724 & c ESO 2007 Astrophysics The XMM-Newton extended survey of the Taurus molecular cloud Special feature The XMM-Newton extended survey of the Taurus molecular cloud (XEST), M. Güdel1, K. R. Briggs1, K. Arzner1, M. Audard2,, J. Bouvier3, E. D. Feigelson4, E. Franciosini5, A. Glauser1, N. Grosso3, G. Micela5, J.-L. Monin3, T. Montmerle3, D. L. Padgett6, F. Palla7, I. Pillitteri8, L. Rebull6, L. Scelsi8, B. Silva9,10, S. L. Skinner11, B. Stelzer5, and A. Telleschi1 1 Paul Scherrer Institut, Würenlingen and Villigen, 5232 Villigen PSI, Switzerland e-mail: [email protected] 2 Columbia Astrophysics Laboratory, Mail Code 5247, 550 West 120th Street, New York, NY 10027, USA 3 Laboratoire d’Astrophysique de Grenoble, Université Joseph Fourier - CNRS, BP 53, 38041 Grenoble Cedex, France 4 Department of Astronomy & Astrophysics, Penn State University, 525 Davey Lab, University Park, PA 16802, USA 5 INAF - Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy 6 Spitzer Science Center, California Institute of Technology, Mail Code 220-6, Pasadena, CA 91125, USA 7 INAF - Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi, 5, 50125 Firenze, Italy 8 Dipartimento di Scienze Fisiche ed Astronomiche, Università di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy 9 Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150 Porto, Portugal 10 Departamento de Matemática Aplicada, Faculdade de Ciêcias da Universidade do Porto, 4169 Porto, Portugal 11 CASA, 389, University of Colorado, Boulder, CO 80309-0389, USA Received 31 May 2006 / Accepted 5 August 2006 ABSTRACT Context.
    [Show full text]
  • Spitzer Irs Spectra and Envelope Models of Class I Protostars in Taurus E
    The Astrophysical Journal Supplement Series, 176:184Y215, 2008 May A # 2008. The American Astronomical Society. All rights reserved. Printed in U.S.A. SPITZER IRS SPECTRA AND ENVELOPE MODELS OF CLASS I PROTOSTARS IN TAURUS E. Furlan,1,2,3 M. McClure,4 N. Calvet,5 L. Hartmann,5 P. D’Alessio,6 W. J. Forrest,4 D. M. Watson,4 K. I. Uchida,1 B. Sargent,4 J. D. Green,4 and T. L. Herter1 Received 2007 September 11; accepted 2007 November 18 ABSTRACT We present Spitzer Infrared Spectrograph (IRS) spectra of 28 Class I protostars in the Taurus star-forming region. The 5Y36 m spectra reveal excess emission from the inner regions of the envelope and accretion disk surrounding these predecessors of low-mass stars, as well as absorption features due to silicates and ices. Together with shorter and longer wavelength data from the literature, we construct spectral energy distributions and fit envelope models to 22 protostars of our sample, most of which are well constrained due to the availability of the IRS spectra. We infer that the envelopes of the Class I objects in our sample cover a wide range in parameter space, particularly in density and centrifugal radius, implying different initial conditions for the collapse of protostellar cores. Subject headinggs: circumstellar matter — infrared: stars — stars: formation — stars: preYmain-sequence Online material: color figures 1. INTRODUCTION Besides accreting matter, young stars generate powerful out- flows which are launched along magnetic field lines; mass accre- In a now widely accepted evolutionary sequence based on the tion onto the star and mass loss in the form of outflows seem to shape of the spectral energy distribution (SED) in the infrared, be correlated (e.g., Hartigan et al.
    [Show full text]
  • Self-Organizing Systems in Planetary Physics: Harmonic Resonances Of
    Self-Organizing Systems in Planetary Physics : Harmonic Resonances of Planet and Moon Orbits Markus J. Aschwanden1 1) Lockheed Martin, Solar and Astrophysics Laboratory, Org. A021S, Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304, USA; e-mail: [email protected] ABSTRACT The geometric arrangement of planet and moon orbits into a regularly spaced pattern of distances is the result of a self-organizing system. The positive feedback mechanism that operates a self-organizing system is accomplished by harmonic orbit resonances, leading to long-term stable planet and moon orbits in solar or stellar systems. The distance pattern of planets was originally described by the empirical Titius-Bode law, and by a generalized version with a constant geometric progression factor (corresponding to logarithmic spacing). We find that the orbital periods Ti and planet distances Ri from the Sun are not consistent with logarithmic spacing, 2/3 2/3 but rather follow the quantized scaling (Ri+1/Ri) = (Ti+1/Ti) = (Hi+1/Hi) , where the harmonic ratios are given by five dominant resonances, namely (Hi+1 : Hi)=(3:2), (5 : 3), (2 : 1), (5 : 2), (3 : 1). We find that the orbital period ratios tend to follow the quantized harmonic ratios in increasing order. We apply this harmonic orbit resonance model to the planets and moons in our solar system, and to the exo-planets of 55 Cnc and HD 10180 planetary systems. The model allows us a prediction of missing planets in each planetary system, based on the quasi- regular self-organizing pattern of harmonic orbit resonance zones. We predict 7 (and 4) missing exo-planets around the star 55 Cnc (and HD 10180).
    [Show full text]
  • Observing Dust Grain Growth and Sedimentation in Circumstellar Discs Interpretations and Predictions of Their Observable Quantities in a Multi-Wavelength Approach
    Observing dust grain growth and sedimentation in circumstellar discs Interpretations and predictions of their observable quantities in a multi-wavelength approach Dissertation zur Erlangung des Doktorgrades der Mathematisch-Naturwissenschaftliche Fakult¨at der Christian-Albrechts Universit¨atzu Kiel vorgelegt von J¨urgenSauter Kiel, 2011 Referent : Prof. Dr. S. Wolf Koreferent: Prof. Dr. C. Dullemond Tag der m¨undlichen Pr¨ufung: 7. Juli 2011 Zum Druck genehmigt: 7. Juli 2011 gez. Prof. Dr. L. Kipp, Dekan To my growing family Abstract In the present thesis, the observational effects of dust grain growth and sedimentation in circumstellar discs are investigated. The growth of dust grains from some nanometres in diameter as found in the inter- stellar medium towards planetesimal bodies some meters in diameter is an important step in the formation of planets. However, this process is currently not entirely un- derstood. Especially, in the literature several `barriers' are discussed that apparently prohibit an effective growth of dust grains. Hence, it is of particular interest to compare theories and observational data in this respect. State-of-the-art radiative transfer techniques allow one to derive observable quantities from theoretical models that allow this comparison. In this thesis, generic tracers of dust grain growth in spatially high resolution multi-wavelength images are identified for the first time. Further, a possibility to detect a dust trapping mechanism for dust grains by local pressure maxima using the new interferometer, ALMA, is established. By fitting parametric models to new observations of the disc in the Bok globule CB 26, unexpected features of the system are revealed, such as a large inner void and the possibility to interpret the data without the need for grain growth.
    [Show full text]
  • GERSON DE OLIVEIRA BARBOSA Formação Planetária Em Sistemas
    GERSON DE OLIVEIRA BARBOSA Formação Planetária em Sistemas Binários Guaratinguetá - SP 2016 Gerson de Oliveira Barbosa Formação Planetária em Sistemas Binários Trabalho de Graduação apresentado ao Conselho de Curso de Graduação em Licenciatura em Matemática da Faculdade de Engenharia do Campus de Guaratinguetá, Universidade Estadual Paulista, como parte dos requisitos para obtenção do diploma de Graduação em Licenciatura em Matemática. Orientador: Othon Cabo Winter Coorientador: Rita de Cássia Domingos Guaratinguetá - SP 2016 Barbosa, Gerson de Oliveira Formação planetária em sistemas binários / Gerson de Oliveira B238f Barbosa – Guaratinguetá, 2017. 63f. : il. Bibliografia: f. 61-63 Trabalho de Graduação em Licenciatura em Matemática – Universidade Estadual Paulista, Faculdade de Engenharia de Guaratinguetá, 2017. Orientador: Prof. Dr. Othon Cabo Winter Coorientadora: Rita de Cássia Domingos 1. Exoplanetas. 2. Planetas. 3. Sistema binário (Matemática). 4. Sistema solar. I. Título CDU 523.4 DADOS CURRICULARES NOME COMPLETO DO AUTOR NASCIMENTO 17.08.1987 – Guaratinguetá / SP FILIAÇÃO Geraldo Cotta Barbosa Janaína Fabrício de Oliveira Barbosa 2013/2016 Graduado em Licenciatura em Matemática Universidade Estadual Paulista “Júlio Mesquita Filho” - FEG dedico este trabalho de modo especial, à minha família. AGRADECIMENTOS Agradeço a todos que estiveram comigo nessa jornada e que de alguma forma contribuíram para minha formação. Em especial: Aos meus pais Geraldo Cotta Barbosa e Janaína Fabrício de Oliveira Barbosa, que me ensinaram as principais coisas da vida e confiaram cegamente no meu sucesso. Não sei dizer o quanto tenho orgulho de ser filho de vocês, obrigado meus velhos! Ao meu orientador, Prof. Dr. Othon Cabo Winter que me inspira, motiva e orgulha. Fez- me conhecer a coisa que mais gosto de fazer e sempre ocupou a posição de maior estima e referência.
    [Show full text]
  • Resonant Moons of Neptune
    EPSC Abstracts Vol. 13, EPSC-DPS2019-901-1, 2019 EPSC-DPS Joint Meeting 2019 c Author(s) 2019. CC Attribution 4.0 license. Resonant moons of Neptune Marina Brozović (1), Mark R. Showalter (2), Robert A. Jacobson (1), Robert S. French (2), Jack L. Lissauer (3), Imke de Pater (4) (1) Jet Propulsion Laboratory, California Institute of Technology, California, USA, (2) SETI Institute, California, USA, (3) NASA Ames Research Center, California, USA, (4) University of California Berkeley, California, USA Abstract We used integrated orbits to fit astrometric data of the 2. Methods regular moons of Neptune. We found a 73:69 inclination resonance between Naiad and Thalassa, the 2.1 Observations two innermost moons. Their resonant argument librates around 180° with an average amplitude of The astrometric data cover the period from 1981-2016, ~66° and a period of ~1.9 years. This is the first fourth- with the most significant amount of data originating order resonance discovered between the moons of the from the Voyager 2 spacecraft and HST. Voyager 2 outer planets. The resonance enabled an estimate of imaged all regular satellites except Hippocamp the GMs for Naiad and Thalassa, GMN= between 1989 June 7 and 1989 August 24. The follow- 3 -2 3 0.0080±0.0043 km s and GMT=0.0236±0.0064 km up observations originated from several Earth-based s-2. More high-precision astrometry of Naiad and telescopes, but the majority were still obtained by HST. Thalassa will help better constrain their masses. The [4] published the latest set of the HST astrometry GMs of Despina, Galatea, and Larissa are more including the discovery and follow up observations of difficult to measure because they are not in any direct Hippocamp.
    [Show full text]
  • The UV Perspective of Low-Mass Star Formation
    galaxies Review The UV Perspective of Low-Mass Star Formation P. Christian Schneider 1,* , H. Moritz Günther 2 and Kevin France 3 1 Hamburger Sternwarte, University of Hamburg, 21029 Hamburg, Germany 2 Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research; Cambridge, MA 02109, USA; [email protected] 3 Department of Astrophysical and Planetary Sciences Laboratory for Atmospheric and Space Physics, University of Colorado, Denver, CO 80203, USA; [email protected] * Correspondence: [email protected] Received: 16 January 2020; Accepted: 29 February 2020; Published: 21 March 2020 Abstract: The formation of low-mass (M? . 2 M ) stars in molecular clouds involves accretion disks and jets, which are of broad astrophysical interest. Accreting stars represent the closest examples of these phenomena. Star and planet formation are also intimately connected, setting the starting point for planetary systems like our own. The ultraviolet (UV) spectral range is particularly suited for studying star formation, because virtually all relevant processes radiate at temperatures associated with UV emission processes or have strong observational signatures in the UV range. In this review, we describe how UV observations provide unique diagnostics for the accretion process, the physical properties of the protoplanetary disk, and jets and outflows. Keywords: star formation; ultraviolet; low-mass stars 1. Introduction Stars form in molecular clouds. When these clouds fragment, localized cloud regions collapse into groups of protostars. Stars with final masses between 0.08 M and 2 M , broadly the progenitors of Sun-like stars, start as cores deeply embedded in a dusty envelope, where they can be seen only in the sub-mm and far-IR spectral windows (so-called class 0 sources).
    [Show full text]