DOCSLIB.ORG

UNIVERSITY of CALIFORNIA Los Angeles Analyses of Polluted White

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
UNIVERSITY of CALIFORNIA Los Angeles Analyses of Polluted White UNIVERSITY OF CALIFORNIA Los Angeles Analyses of Polluted White Dwarf Stars with Applications to the Geochemistry of Rocky Exoplanets A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Geochemistry by Alexandra Elyse Doyle 2021 © Copyright by Alexandra Elyse Doyle 2021 ABSTRACT OF THE DISSERTATION Analyses of Polluted White Dwarf Stars with Applications to the Geochemistry of Rocky Exoplanets by Alexandra Elyse Doyle Doctor of Philosophy in Geochemistry University of California, Los Angeles, 2021 Professor Edward Donald Young, Chair In this work, exoplanet-research is combined with the study of the solar system in order to assess differences and similarities between rocky bodies in the Milky Way. To evaluate rocky bodies outside of the solar system, I utilize optical spectroscopy to study polluted white dwarf stars, dense stars that show accretion of planetary material. By observing polluted white dwarfs, we can measure elemental abundances from the rocky and icy bodies that previously orbited the star. Specifically, I conduct observations using the KAST Spectro- graph on the Shane 3-meter telescope at Lick Observatory and the High-Resolution Echelle Spectrometer (HIRES) on the Keck I Telescope, as well as evaluate compiled literature data. Generally, the elemental compositions of extrasolar planetesimals closely resemble those of rocky bodies in the solar system. In this work, a more detailed comparison with solar sys- tem meteorites and planets shows that oxidation of planetesimals prior to planet formation is common among extrasolar rocks. Overall, the processes that lead to the geochemistry and much of the geophysics of Earth is normal compared to the current sample of extrasolar planetesimals. Additionally, the origin of excesses in spallogenic nuclides in polluted white dwarfs is investigated. The MeV proton fluence required to form the high Be/O ratio in the accreted parent bodies of two polluted white dwarfs (GALEX J2339-0424 and GD 378) is consistent with irradiation of ice in the rings of a giant planet within its radiation belt, followed by accretion of the ices to form a moon that is later accreted by the WD. ii The dissertation of Alexandra Elyse Doyle is approved. Kevin D. McKeegan Hilke Elisabet Schlichting Benjamin M. Zuckerman Edward Donald Young, Committee Chair University of California, Los Angeles 2021 iii TABLE OF CONTENTS Abstract of the Dissertation :::::::::::::::::::::::::::::::: ii Committee Page :::::::::::::::::::::::::::::::::::::: iii Table of Contents :::::::::::::::::::::::::::::::::::::: iv List of Figures ::::::::::::::::::::::::::::::::::::::: vi List of Tables :::::::::::::::::::::::::::::::::::::::: viii Acknowledgements ::::::::::::::::::::::::::::::::::::: ix Vita ::::::::::::::::::::::::::::::::::::::::::::: xi Chapter 1: Introduction :::::::::::::::::::::::::::::::::: 1 Chapter 1 References :::::::::::::::::::::::::::::::::::: 5 Chapter 2: Oxygen Fugacities of Extrasolar Rocks: Evidence for an Earth-like Geochem- istry of Exoplanets ::::::::::::::::::::::::::::::::::::: 6 Appendix A ::::::::::::::::::::::::::::::::::::::::: 17 Appendix B ::::::::::::::::::::::::::::::::::::::::: 40 Appendix C ::::::::::::::::::::::::::::::::::::::::: 52 Chapter 2 References :::::::::::::::::::::::::::::::::::: 58 Chapter 3: Where are the Extrasolar Mercuries? :::::::::::::::::::: 65 Appendix D ::::::::::::::::::::::::::::::::::::::::: 104 Chapter 3 References :::::::::::::::::::::::::::::::::::: 106 iv Chapter 4: Discovery of Beryllium in White Dwarfs Polluted by Planetesimal Accretion115 Appendix E ::::::::::::::::::::::::::::::::::::::::: 156 Chapter 4 References :::::::::::::::::::::::::::::::::::: 160 Chapter 5: Icy Exomoons Evidenced by Spallogenic Nuclides in Polluted White Dwarfs 173 Chapter 5 References :::::::::::::::::::::::::::::::::::: 195 Chapter 6: Future Work :::::::::::::::::::::::::::::::::: 203 Chapter 6 References :::::::::::::::::::::::::::::::::::: 207 v LIST OF FIGURES 2.1 Bulk compositions of solar system bodies and 6 WDs . 13 2.2 ∆IW at core formation vs today . 14 2.3 Calculated ∆IW for 6 rocky extrasolar bodies . 15 2.4 Summary diagram of bootstrap method . 31 2.5 Comparison of analytical and bootstrap methods . 32 2.6 Frequency distributions from bootstrap analysis for WDs . 33 2.7 Frequency distributions from bootstrap analysis for solar system rocks . 34 2.8 Variations in calculated ∆IW for WD GD 40 . 35 2.9 Logarithm of oxygen fugacity vs temperature . 36 3.1 Bulk compositions of solar system bodies and 16 WDs . 90 rock 3.2 Cumulative frequency distributions for xFeO for 2 WDs . 91 rock 3.3 Comparison of parent body xFeO describing origin of upper limits . 92 3.4 Comparison of parent body ∆IW from our 2 methods . 93 rock 3.5 Cumulative frequency distributions for xFeO for 16 WDs . 94 3.6 ∆IW versus Oxs/Fe.................................. 95 3.7 Model for accretion histories of example DA and DB WDs . 96 3.8 Evolution of ∆IW for CI chondrite material in WDs with various Teff . 97 3.9 Evolution of bulk composition and ∆IW for a reduced body . 98 3.10 Evolution of molar abundances in WD atmosphere for a reduced body . 99 3.11 Evolution of ∆IW for a reduced body in WDs with various Teff . 100 3.12 Evolution of ∆IW for a reduced body with <4% Fe core in WDs with various Teff 101 3.13 Comparison of ∆IW in steady-state vs build-up assumption . 102 4.1 Be II detection in spectrum of GALEX J2339-0424 . 137 vi 4.2 Be II detection in spectrum of GD 378 . 138 4.3 Distribution of radial velocities for GALEX J2339-0424 . 139 4.4 Distribution of radial velocities for GD 378 . 140 4.5 SED for GALEX J2339-0424 . 141 4.6 SED for GD 378 . 142 4.7 Element detections in spectrum for GALEX J2339-0424 . 143 4.8 Lighter element detections in spectra for GD 378 . 144 4.9 Heavier element detections in spectra for GD 378 . 145 4.10 Be II region in spectrum of GD 362 . 146 4.11 Various abundance ratios by number for WDs and solar system objects . 147 5.1 Element/Fe ratios for GALEX J2339-0424 parent body relative to various rocks 190 5.2 Reduced chi-squared for fits of GALEX J2339-0424 parent body to various rocks 191 5.3 Optimal accretion durations vs τdisk . 192 5.4 Diagram of proposed formation environment for ices enriched in Be . 193 6.1 Log abundance by number for Mg and Na normalized to Ca . 206 vii LIST OF TABLES 2.1 Parameters for WDs in Chapter 2 . 16 2.2 Elemental compositions of solar system rocks and WDs . 37 2.3 Input values for solar system rocks and WDs into ∆IW calculation . 38 3.1 Parameters and ∆IW values for WDs in Chapter 3 . 103 4.1 Historical element discoveries in cool polluted WDs . 148 4.2 Absorption Lines in GALEX J2339−0424 . 149 4.3 Absorption Lines in GD 378 . 150 4.4 Parameters for GALEX J2339-0424 and GD 378 . 151 4.5 Be ratios relative to CI chondrite for various astronomical objects . 152 4.6 Elemental abundances for GALEX J2339−0424 . 153 4.7 Elemental abundances for GD 378 . 154 4.8 Be upper limits in polluted WDs . 155 4.9 UV-Optical abundance comparison for GD 378 . 159 5.1 Elemental abundances for GALEX J2339-0424 . 194 viii ACKNOWLEDGMENTS Chapter 2 is a version of Doyle, A. E., Young, E. D., Klein, B., Zuckerman, B., and Schlicht- ing, H. E. (2019) Oxygen fugacities of extrasolar rocks: evidence for an Earth-like geochem- istry of exoplanets. Science, 366, 356-359. DOI: 10.1126/science.aax3901. A.E.D. performed the calculations and co-wrote the manuscript. E.D.Y. conceived of the project, supervised the calculations, and co-wrote the manuscript. B.Z. and B.K. analyzed the WD data. H.E.S. contributed to the statistical analysis. All authors contributed to the interpretation of the data and the preparation of the paper. E.D.Y. acknowledges support from the NASA Exo- planets program grant NNX16AB53G. A.E.D. acknowledges financial support from NASA Space Grant. H.E.S. gratefully acknowledges support from the National Aeronautics and Space Administration under grant 17 NAI18 2-0029 issued through the NExSS Program. Chapter 3 is a version of Doyle, A. E., Klein, B., Schlichting, H. E., and Young, E. D. (2020) Where are the Extrasolar Mercuries? Ap.J., 901, 10. DOI: 10.3847/1538- 4357/abad9a. A.E.D. performed the calculations and analyzed the WD data. B.K. assisted in analysis of WD data. H.E.S. provided the statistical framework for the treatment of WD data. E.D.Y. supervised the calculations. A.E.D. and E.D.Y. co-wrote the manuscript. This work was supported by NASA 2XRP grant No. 80NSSC20K0270 to E.D.Y.. H.E.S. grate- fully acknowledges support from the National Aeronautics and Space Administration under grant No. 17 NAI18 2-0029 issued through the NExSS Program. Chapter 4 is a version of Klein, B., Doyle, A. E., Zuckerman, B., Dufour, P., Blouin, S., Melis, C., Weinberger, A., and Young, E. D. Discovery of Beryllium in White Dwarfs Pol- luted by Accreted Planetesimals. Ap.J., accepted. A.E.D. was involved in observations using the KAST spectrograph, combining and normalizing spectra, iterations of the model atmo- spheres, creating the SED for GALEX J2339-0424 (Figure 4.5), making preliminary line lists (versions of those in Tables 4.2 and 4.3), and co-identifying the Be spectral lines. B.K. was supported by the A.P.S. M. Hildred Blewett Fellowship. A.E.D. and B.K. acknowledge sup- port from the NASA Exoplanets program award number 80NSSC20K0270 to E.D.Y.. Partial support was also provided by other NASA grants to UCLA. S.B. acknowledges support from ix the Laboratory Directed Research and Development program of Los Alamos National Lab- oratory under project number 20190624PRD2. C.M. and B.Z. acknowledge support from NSF grants SPG-1826583 and SPG-1826550. Chapter 5 is a version of Doyle, A. E., Desch, S. J., and Young, E. D. (2021) Icy Ex- omoons Evidenced by Spallogenic Nuclides in Polluted White Dwarfs. Ap.J.L., 907, L35. DOI: 10.3847/2041-8213/abd9ba. A.E.D. performed the composition calculations. S.J.D. suggested the formation environment for the parent body.
Load more

Recommended publications
  • Lurking in the Shadows: Wide-Separation Gas Giants As Tracers of Planet Formation
    Lurking in the Shadows: Wide-Separation Gas Giants as Tracers of Planet Formation Thesis by Marta Levesque Bryan In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy CALIFORNIA INSTITUTE OF TECHNOLOGY Pasadena, California 2018 Defended May 1, 2018 ii © 2018 Marta Levesque Bryan ORCID: [0000-0002-6076-5967] All rights reserved iii ACKNOWLEDGEMENTS First and foremost I would like to thank Heather Knutson, who I had the great privilege of working with as my thesis advisor. Her encouragement, guidance, and perspective helped me navigate many a challenging problem, and my conversations with her were a consistent source of positivity and learning throughout my time at Caltech. I leave graduate school a better scientist and person for having her as a role model. Heather fostered a wonderfully positive and supportive environment for her students, giving us the space to explore and grow - I could not have asked for a better advisor or research experience. I would also like to thank Konstantin Batygin for enthusiastic and illuminating discussions that always left me more excited to explore the result at hand. Thank you as well to Dimitri Mawet for providing both expertise and contagious optimism for some of my latest direct imaging endeavors. Thank you to the rest of my thesis committee, namely Geoff Blake, Evan Kirby, and Chuck Steidel for their support, helpful conversations, and insightful questions. I am grateful to have had the opportunity to collaborate with Brendan Bowler. His talk at Caltech my second year of graduate school introduced me to an unexpected population of massive wide-separation planetary-mass companions, and lead to a long-running collaboration from which several of my thesis projects were born.
    [Show full text]
  • Exomoon Habitability Constrained by Illumination and Tidal Heating
    submitted to Astrobiology: April 6, 2012 accepted by Astrobiology: September 8, 2012 published in Astrobiology: January 24, 2013 this updated draft: October 30, 2013 doi:10.1089/ast.2012.0859 Exomoon habitability constrained by illumination and tidal heating René HellerI , Rory BarnesII,III I Leibniz-Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany, [email protected] II Astronomy Department, University of Washington, Box 951580, Seattle, WA 98195, [email protected] III NASA Astrobiology Institute – Virtual Planetary Laboratory Lead Team, USA Abstract The detection of moons orbiting extrasolar planets (“exomoons”) has now become feasible. Once they are discovered in the circumstellar habitable zone, questions about their habitability will emerge. Exomoons are likely to be tidally locked to their planet and hence experience days much shorter than their orbital period around the star and have seasons, all of which works in favor of habitability. These satellites can receive more illumination per area than their host planets, as the planet reflects stellar light and emits thermal photons. On the contrary, eclipses can significantly alter local climates on exomoons by reducing stellar illumination. In addition to radiative heating, tidal heating can be very large on exomoons, possibly even large enough for sterilization. We identify combinations of physical and orbital parameters for which radiative and tidal heating are strong enough to trigger a runaway greenhouse. By analogy with the circumstellar habitable zone, these constraints define a circumplanetary “habitable edge”. We apply our model to hypothetical moons around the recently discovered exoplanet Kepler-22b and the giant planet candidate KOI211.01 and describe, for the first time, the orbits of habitable exomoons.
    [Show full text]
  • JOHN R. THORSTENSEN Address
    CURRICULUM VITAE: JOHN R. THORSTENSEN Address: Department of Physics and Astronomy Dartmouth College 6127 Wilder Laboratory Hanover, NH 03755-3528; (603)-646-2869 [email protected] Undergraduate Studies: Haverford College, B. A. 1974 Astronomy and Physics double major, High Honors in both. Graduate Studies: Ph. D., 1980, University of California, Berkeley Astronomy Department Dissertation : \Optical Studies of Faint Blue X-ray Stars" Graduate Advisor: Professor C. Stuart Bowyer Employment History: Department of Physics and Astronomy, Dartmouth College: { Professor, July 1991 { present { Associate Professor, July 1986 { July 1991 { Assistant Professor, September 1980 { June 1986 Research Assistant, Space Sciences Lab., U.C. Berkeley, 1975 { 1980. Summer Student, National Radio Astronomy Observatory, 1974. Summer Student, Bartol Research Foundation, 1973. Consultant, IBM Corporation, 1973. (STARMAP program). Honors and Awards: Phi Beta Kappa, 1974. National Science Foundation Graduate Fellow, 1974 { 1977. Dorothea Klumpke Roberts Award of the Berkeley Astronomy Dept., 1978. Professional Societies: American Astronomical Society Astronomical Society of the Pacific International Astronomical Union Lifetime Publication List * \Can Collapsed Stars Close the Universe?" Thorstensen, J. R., and Partridge, R. B. 1975, Ap. J., 200, 527. \Optical Identification of Nova Scuti 1975." Raff, M. I., and Thorstensen, J. 1975, P. A. S. P., 87, 593. \Photometry of Slow X-ray Pulsars II: The 13.9 Minute Period of X Persei." Margon, B., Thorstensen, J., Bowyer, S., Mason, K. O., White, N. E., Sanford, P. W., Parkes, G., Stone, R. P. S., and Bailey, J. 1977, Ap. J., 218, 504. \A Spectrophotometric Survey of the A 0535+26 Field." Margon, B., Thorstensen, J., Nelson, J., Chanan, G., and Bowyer, S.
    [Show full text]
  • Arxiv:2105.11583V2 [Astro-Ph.EP] 2 Jul 2021 Keck-HIRES, APF-Levy, and Lick-Hamilton Spectrographs
    Draft version July 6, 2021 Typeset using LATEX twocolumn style in AASTeX63 The California Legacy Survey I. A Catalog of 178 Planets from Precision Radial Velocity Monitoring of 719 Nearby Stars over Three Decades Lee J. Rosenthal,1 Benjamin J. Fulton,1, 2 Lea A. Hirsch,3 Howard T. Isaacson,4 Andrew W. Howard,1 Cayla M. Dedrick,5, 6 Ilya A. Sherstyuk,1 Sarah C. Blunt,1, 7 Erik A. Petigura,8 Heather A. Knutson,9 Aida Behmard,9, 7 Ashley Chontos,10, 7 Justin R. Crepp,11 Ian J. M. Crossfield,12 Paul A. Dalba,13, 14 Debra A. Fischer,15 Gregory W. Henry,16 Stephen R. Kane,13 Molly Kosiarek,17, 7 Geoffrey W. Marcy,1, 7 Ryan A. Rubenzahl,1, 7 Lauren M. Weiss,10 and Jason T. Wright18, 19, 20 1Cahill Center for Astronomy & Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA 2IPAC-NASA Exoplanet Science Institute, Pasadena, CA 91125, USA 3Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305, USA 4Department of Astronomy, University of California Berkeley, Berkeley, CA 94720, USA 5Cahill Center for Astronomy & Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA 6Department of Astronomy & Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802, USA 7NSF Graduate Research Fellow 8Department of Physics & Astronomy, University of California Los Angeles, Los Angeles, CA 90095, USA 9Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA 10Institute for Astronomy, University of Hawai`i,
    [Show full text]
  • UC Irvine UC Irvine Previously Published Works
    UC Irvine UC Irvine Previously Published Works Title Astrophysics in 2006 Permalink https://escholarship.org/uc/item/5760h9v8 Journal Space Science Reviews, 132(1) ISSN 0038-6308 Authors Trimble, V Aschwanden, MJ Hansen, CJ Publication Date 2007-09-01 DOI 10.1007/s11214-007-9224-0 License https://creativecommons.org/licenses/by/4.0/ 4.0 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Space Sci Rev (2007) 132: 1–182 DOI 10.1007/s11214-007-9224-0 Astrophysics in 2006 Virginia Trimble · Markus J. Aschwanden · Carl J. Hansen Received: 11 May 2007 / Accepted: 24 May 2007 / Published online: 23 October 2007 © Springer Science+Business Media B.V. 2007 Abstract The fastest pulsar and the slowest nova; the oldest galaxies and the youngest stars; the weirdest life forms and the commonest dwarfs; the highest energy particles and the lowest energy photons. These were some of the extremes of Astrophysics 2006. We attempt also to bring you updates on things of which there is currently only one (habitable planets, the Sun, and the Universe) and others of which there are always many, like meteors and molecules, black holes and binaries. Keywords Cosmology: general · Galaxies: general · ISM: general · Stars: general · Sun: general · Planets and satellites: general · Astrobiology · Star clusters · Binary stars · Clusters of galaxies · Gamma-ray bursts · Milky Way · Earth · Active galaxies · Supernovae 1 Introduction Astrophysics in 2006 modifies a long tradition by moving to a new journal, which you hold in your (real or virtual) hands. The fifteen previous articles in the series are referenced oc- casionally as Ap91 to Ap05 below and appeared in volumes 104–118 of Publications of V.
    [Show full text]
  • The Maunder Minimum and the Variable Sun-Earth Connection
    The Maunder Minimum and the Variable Sun-Earth Connection (Front illustration: the Sun without spots, July 27, 1954) By Willie Wei-Hock Soon and Steven H. Yaskell To Soon Gim-Chuan, Chua Chiew-See, Pham Than (Lien+Van’s mother) and Ulla and Anna In Memory of Miriam Fuchs (baba Gil’s mother)---W.H.S. In Memory of Andrew Hoff---S.H.Y. To interrupt His Yellow Plan The Sun does not allow Caprices of the Atmosphere – And even when the Snow Heaves Balls of Specks, like Vicious Boy Directly in His Eye – Does not so much as turn His Head Busy with Majesty – ‘Tis His to stimulate the Earth And magnetize the Sea - And bind Astronomy, in place, Yet Any passing by Would deem Ourselves – the busier As the Minutest Bee That rides – emits a Thunder – A Bomb – to justify Emily Dickinson (poem 224. c. 1862) Since people are by nature poorly equipped to register any but short-term changes, it is not surprising that we fail to notice slower changes in either climate or the sun. John A. Eddy, The New Solar Physics (1977-78) Foreword By E. N. Parker In this time of global warming we are impelled by both the anticipated dire consequences and by scientific curiosity to investigate the factors that drive the climate. Climate has fluctuated strongly and abruptly in the past, with ice ages and interglacial warming as the long term extremes. Historical research in the last decades has shown short term climatic transients to be a frequent occurrence, often imposing disastrous hardship on the afflicted human populations.
    [Show full text]
  • Binocular Double Star Logbook
    Astronomical League Binocular Double Star Club Logbook 1 Table of Contents Alpha Cassiopeiae 3 14 Canis Minoris Sh 251 (Oph) Psi 1 Piscium* F Hydrae Psi 1 & 2 Draconis* 37 Ceti Iota Cancri* 10 Σ2273 (Dra) Phi Cassiopeiae 27 Hydrae 40 & 41 Draconis* 93 (Rho) & 94 Piscium Tau 1 Hydrae 67 Ophiuchi 17 Chi Ceti 35 & 36 (Zeta) Leonis 39 Draconis 56 Andromedae 4 42 Leonis Minoris Epsilon 1 & 2 Lyrae* (U) 14 Arietis Σ1474 (Hya) Zeta 1 & 2 Lyrae* 59 Andromedae Alpha Ursae Majoris 11 Beta Lyrae* 15 Trianguli Delta Leonis Delta 1 & 2 Lyrae 33 Arietis 83 Leonis Theta Serpentis* 18 19 Tauri Tau Leonis 15 Aquilae 21 & 22 Tauri 5 93 Leonis OΣΣ178 (Aql) Eta Tauri 65 Ursae Majoris 28 Aquilae Phi Tauri 67 Ursae Majoris 12 6 (Alpha) & 8 Vul 62 Tauri 12 Comae Berenices Beta Cygni* Kappa 1 & 2 Tauri 17 Comae Berenices Epsilon Sagittae 19 Theta 1 & 2 Tauri 5 (Kappa) & 6 Draconis 54 Sagittarii 57 Persei 6 32 Camelopardalis* 16 Cygni 88 Tauri Σ1740 (Vir) 57 Aquilae Sigma 1 & 2 Tauri 79 (Zeta) & 80 Ursae Maj* 13 15 Sagittae Tau Tauri 70 Virginis Theta Sagittae 62 Eridani Iota Bootis* O1 (30 & 31) Cyg* 20 Beta Camelopardalis Σ1850 (Boo) 29 Cygni 11 & 12 Camelopardalis 7 Alpha Librae* Alpha 1 & 2 Capricorni* Delta Orionis* Delta Bootis* Beta 1 & 2 Capricorni* 42 & 45 Orionis Mu 1 & 2 Bootis* 14 75 Draconis Theta 2 Orionis* Omega 1 & 2 Scorpii Rho Capricorni Gamma Leporis* Kappa Herculis Omicron Capricorni 21 35 Camelopardalis ?? Nu Scorpii S 752 (Delphinus) 5 Lyncis 8 Nu 1 & 2 Coronae Borealis 48 Cygni Nu Geminorum Rho Ophiuchi 61 Cygni* 20 Geminorum 16 & 17 Draconis* 15 5 (Gamma) & 6 Equulei Zeta Geminorum 36 & 37 Herculis 79 Cygni h 3945 (CMa) Mu 1 & 2 Scorpii Mu Cygni 22 19 Lyncis* Zeta 1 & 2 Scorpii Epsilon Pegasi* Eta Canis Majoris 9 Σ133 (Her) Pi 1 & 2 Pegasi Δ 47 (CMa) 36 Ophiuchi* 33 Pegasi 64 & 65 Geminorum Nu 1 & 2 Draconis* 16 35 Pegasi Knt 4 (Pup) 53 Ophiuchi Delta Cephei* (U) The 28 stars with asterisks are also required for the regular AL Double Star Club.
    [Show full text]
  • The HR Diagram
    Name_______________________ Class_______________________ Date_______________________ Assignment #10 – The H-R Diagram A star is a delicately balanced ball of gas, fighting between two impulses: gravity, which wants to squeeze the gas all down to a single point, and radiation pressure, which wants to blast all the gas out to infinity. These two opposite forces balance out in a process called Hydrostatic Equilibrium, and keep the gas at a stable, fairly constant size. The radiation itself is due to the fusion of protons in the star's core – a process that produces huge amounts of energy. In class we've examined the most important properties of stars: their temperatures, colors and brightnesses. Now let's see if we can find some relationships between these stellar properties. We know that hotter stars are brighter, as described by the Stefan-Boltzmann Law, and we know that the hotter stars are also bluer, as described by Wien's Law. The H-R diagram is a way of displaying an important relationship between a star's Absolute Magnitude (or Luminosity), and its Spectral Type (or temperature). Remember, Absolute Magnitude is how bright a star would appear to be, if it were 10 parsecs away. Luminosity is how much total energy a star gives off per second. As we studied in a previous exercise, Spectral Type is a system of classifying stars by temperature, from hottest (type O) to coldest (type M). Each letter in the Spectral Type list (O, B, A, F, G, K, and M) is further subdivided into 10 steps, numbered 0 through 9, to make finer distinctions between stars.
    [Show full text]
  • Dust in Brown Dwarfs and Extrasolar Planets V
    A&A 603, A123 (2017) Astronomy DOI: 10.1051/0004-6361/201629696 & c ESO 2017 Astrophysics Dust in brown dwarfs and extrasolar planets V. Cloud formation in carbon- and oxygen-rich environments Ch. Helling, D. Tootill, P. Woitke, and G. Lee Centre for Exoplanet Science, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS, UK e-mail: [email protected] Received 12 September 2016 / Accepted 6 December 2016 ABSTRACT Context. Recent observations indicate potentially carbon-rich (C/O > 1) exoplanet atmospheres. Spectral fitting methods for brown dwarfs and exoplanets have invoked the C/O ratio as additional parameter but carbon-rich cloud formation modeling is a challenge for the models applied. The determination of the habitable zone for exoplanets requires the treatment of cloud formation in chemically different regimes. Aims. We aim to model cloud formation processes for carbon-rich exoplanetary atmospheres. Disk models show that carbon-rich or near-carbon-rich niches may emerge and cool carbon planets may trace these particular stages of planetary evolution. Methods. We extended our kinetic cloud formation model by including carbon seed formation and the formation of C[s], TiC[s], SiC[s], KCl[s], and MgS[s] by gas-surface reactions. We solved a system of dust moment equations and element conservation for a prescribed Drift-Phoenix atmosphere structure to study how a cloud structure would change with changing initial C/O0 = 0:43 ::: 10:0. Results. The seed formation efficiency is lower in carbon-rich atmospheres than in oxygen-rich gases because carbon is a very effective growth species.
    [Show full text]
  • Habitable Environments in Late Stellar Evolution
    Habitable Environments in Late Stellar Evolution Conditions for Abiogenesis in the Planetary Systems of White Dwarfs Author: Dewy Peters Supervisor: Prof. dr. F.F.S. van der Tak A thesis submitted in fulfillment of the requirements for the degree BSc in Astronomy Faculty of Science and Engineering University of Groningen The Netherlands March 2021 Abstract With very high potential transit-depths and an absence of stellar flare activity, the planets of White Dwarfs (WDs) are some of the most promising in the search for detectable life. Whilst planets with Earth-like masses and radii have yet to be detected around WDs, there is considerable evidence from spectroscopic and photometric observations that both terrestrial and gas-giant planets are capable of surviving post-main sequence evolution and migrating into the WD phase. WDs are also capable of hosting stable Habitable Zones outside orbital distances at which Earth-mass plan- ets would be disintegrated by tidal forces. Whilst transition- ing to the WD Phase, a main-sequence star has to progress along the Asymptotic Giant Branch (AGB), whereby orbit- ing planets would be subjected to atmospheric erosion by its harsh stellar winds. As a trade-off, the Circumstellar En- velope (CSE) of an AGB star is found to be rich in organics and some of the simple molecules from which more complex prebiotic molecules such as amino acids and simple sugars can be synthesised. It is found that planets with initial or- bital distances equivalent to those of Saturn and the Kuiper Belt would be capable of accreting a mass between 1 and 20 times that of the Earth’s atmosphere from the CSE and as a result, could obtain much of the material necessary to sustain life after the AGB and also experience minimal at- mospheric erosion.
    [Show full text]
  • 1. Attach Your Completed H-R Diagram…Along with Procedure Steps 2 & 3
    Lab: Classifying Stars Name: ________________________ Earth Science Date: ________________ Hr: ____ Introduction: Astronomers use two basic properties of stars to classify them. These two properties are luminosity, or brightness, and surface temperature. Astronomers will often use a star’s color to measure it’s temperature. Stars with low temperature produce a reddish light, while stars with high temperature shine with a brilliant blue white light. Surface temperatures of stars range from 2,000 Kelvin to 50,000 Kelvin. When these surface temperatures are plotted on a graph against luminosity, the stars fall into 3 groups: Main Sequence, Giants, and White Dwarfs. Question: When plotting stars using brightness and temperature, what group do most stars belong to? Hypothesis: Procedure: 1. Plot the stars listed below on the graph provided. 2. Circle around/label each group of stars (Main Sequence, Giants/Supergiants, White Dwarfs). 3. Find the Sun and make its DOT darker. OBSERVATIONS: Table #1: Star Brightness and Surface Temperature Star Brightness (x Sun) Surface Temperature ( x 1000 K) Rigel 10,000 11 Polaris 2,500 6 Antares 65,000 3 Van Maanen 2 0.001 6.2 Spica 12,000 22 Vega 40 10 Procyon A 7 6.5 Regulus 150 10.3 Lacaille 0.02 3.6 Sirius B 0.01 10 Betelgeuse 100,000 3 Achernar 3,100 15 Aldebaran 500 4 Tau Ceti 0.5 5.3 Sirius A 25 10 Sun 1 5.7 Procyon B 0.004 8 Altair 10.8 8 Alpha Centauri A 1.6 5.7 Eridani B 0.08 16 ------------------EVERYTHING MUST BE HAND-WRITTEN FROM THIS POINT ON----------------------- Analysis: 1.
    [Show full text]
  • Intervening Material in Sight-Lines Towards Grbs and Qsos
    Programa de Doctorado en F´ısica y Matem´aticas Universidad de Granada Cosmic Lighthouses at High Redshift: Intervening material in sight-lines towards GRBs and QSOs Rub´en S´anchez Ram´ırez Thesis submitted for the degree of Doctor of Philosophy 10 June 2016 Supervisors: Prof. Javier Gorosabel Urkia, Dr. Antonio de Ugarte Postigo, and Prof. Alberto J. Castro Tirado Instituto de Astrof´ısica de Andaluc´ıa Consejo Superior de Investigaciones Cient´ıficas Para todos aquellos que caminaron a mi lado, a´unsin yo mismo entender hacia d´ondeme dirig´ıa... ii In Memoriam Javier Gorosabel Urquia (1969 - 2015) “El polvo de las estrellas se convirti´oun dia en germen de vida. Y de ´elsurgimos nosotros en algun momento. Y asi vivimos, creando y recreando nuestro ambito. Sin descanso. Trabajando pervivimos. Y a esa dura cadena estamos todos atados.” — Izarren Hautsa, Mikel Laboa “La vida son estos momentos que luego se te olvidan”. Esa fue la conclusi´on a la que lleg´oJavier al final de uno de esos fant´asticos d´ıas intensos y maratonianos a los que me ten´ıa acostumbrado. Vi´endolo ahora con perspectiva estaba en lo cierto, porque por m´as que me esfuerce en recordar y explicar lo que era el d´ıa a d´ıa con ´el, no puedo transmitir con justicia lo que realmente fue. La reconstrucci´on de esos momentos es inevitablemente incompleta. Contaros c´omo era Javier como jefe es muy sencillo: ´el nunca se comport´ocomo un jefe conmigo. Nunca orden´o. Siempre me dec´ıa, lleno de orgullo, que no le hac´ıa ni caso.
    [Show full text]