DOCSLIB.ORG

Quantum Statistical Mechanics for Stellar Astrophysics

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Quantum Statistical Mechanics for Stellar Astrophysics Quantum Statistical Mechanics for Stellar Astrophysics Branislav K. Nikolić Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, U.S.A. http://wiki.physics.udel.edu/phys813 PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics Light Emitted by Stars: Why is the Radiation from the Sun so Stable? STELLAR ASTROPHYSICS: four fundamental forces of nature come into play in a characteristic and spectacular manner → the stars are formed by a collapse of matter caused by gravitational attraction; the light that they emit is generated by electromagnetic interactions; strong interactions provide their main source of energy; and weak interactions contribute in a crucial way to make their lifetime so long. Sun as a main sequence star: 1937 Bethe and von Weiszäcker: nuclear fusion of hydrogen into helium that take place in the central part of the Sun produce some amount of heat per unit time, which is exactly equal to the luminosity because the state of the Sun is stationary. However, such reactions are very sensitive to small changes in the temperature: they are activated by a rise, hindered by a decrease. Thus, if it happens at some instant that a little more power is produced in the core than what is evacuated by radiation from the surface, why does the internal temperature not rise, eventually resulting in an explosion of the Sun? Conversely if the opposite perturbation occurs, why does the Sun not become extinct? dE stability of stellar equilibrium =−=+QLbut E EU ensured by gravitational force dt total gravity PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics Hertzsprung–Russell Diagram and Evolution of Solar-Mass Stars PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics Nucleosynthesis and Fusion Reactions inside Main Sequence Stars In both proton-proton chain and CNO cycle Coulomb repulsion must be overcome to initiate fusion, which involves quantum tunneling and requires extremely high kinetic energy of fusing particles. The CNO cycle becomes the chief source of energy in stars of 1.5 solar masses or higher. PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics Internal Structure of Post-Main Sequence Stars in Pictures PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics Pressure due to Classical Thermal Motion Acts Against Gravity Collapse in Main Sequence Stars 2 GM star wants to contract to a state of lower energy (i.e., larger negative values of U), U ≈− unless there is outward direct pressure to resist the contraction R in ordinary stars with fuel for thermnuclear fusion, outward PV= NkB T pressure is provided bythermal motion ρGM NmkTρ kT ≈=BBgravitation pressure at the center of the star 2R Vm m is equal to thermal pressure GM 2 ≈−U ≈ Nk T total thermal energy is comparable to the magnitude R B of total gravitational potential energy PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics White Dwarfs Stabilized by Fermi Pressure of Non-Relativistic Electrons AZ,, A−= Z , x Z A atomic number, number of protons, number of neutrons, electron fraction mass of star, number of electrons M≈= Nmpe, N xN 2 2 23 pF h 3Ne ε F = = Fermi energy of electron gas in non-relativistic approximation 2mmVee 28π 3 EN= ε Total kinetic energy of electron gas e5 eF 22 3 3GN mp ER()= Nε − Total energy of cool star where thermal energy can be neglected 55eF R 23 d xh2 91 =⇒= White dwarfs cool off and contract to this radius ERR() 0 22xN dR 44mepπ GNM 1 3 M=0.85 MN , = 1057 , x =⇒≈ R8000 km, ρ=3 × 106 g cm 2 PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics White Dwarfs Stabilized by Fermi Pressure of Relativistic Electrons 13 3N phF = 8πV energy per electron increases with N, so when it becomes comparable to pFe mc ε =2 2 +− 24 2 → mc2 we have to switch to relativistic Fc p Fe mc mc e p F c energy-momentum dispersion 13 22 for simplicity we assume uniform density 39xNhc 3GN mp = − assumed, while in reality density is larger in the ER() 2 xN 84RRπ 5 center of the star than further out both terms depend on R, so total anergy of star decreases continously with decreasing radius 13 22 39xN hc 3GN m 312 32 =⇔ c =cp ⇒= ππ22 ER( ) 0 2 xNccN (125) x( hc 2 Gmp) 8RR 4π 5 16 57 N0 =2.2 ⋅ 10 2 numerically exact result called “Chandrasekhar x limiting mass” as the largest mass a white dwarf Nc=0.7N0 ⇒= Nmcp 1.4 M can have and still cool off to a stable cold state 0.5 with finite radius and density PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics Neutron Stars Stabilized by Fermi Pressure of Neutrons epn− + →+ν E(R) could be lowered still further by changing x through inverse beta decay which requires electrons with large kinetic energy 33 8ππmcen0.97 6 3 11 3 8 mc 6 15 3 mmpp= ×10 g cm 10 g cm <<ρ = ×10 g cm 3xh x 3(1−−x ) h 1 x density of star at which Fermi neutrons remain non-relativistic below this density momentum of electrons equals mec neutrons become more abundant than protons at these densities ERx(,)=++ E E E neglects energy of protons (since they are small fraction neutron electron gravitation of nucleons in neutron star) and nuclear forces 23 13 3 (1− x ) Nh2 9 3xNhc 9 3GN22 m = −+ −p 22(1x ) N 2xN 58Rmp 4ππ 8R 4 5R 2 23 neutrons star radius h 9 −1 =⇒= 2 is about 1000 times ∂∂ x0 R 2 N( GNmp ) smaller than the ERx(,)= 0; ERx (,)= 0 ⇒ 44mp π ∂∂Rx white dwarf radius 14 3 M= MR ; = 12.6 km; ρ=2.4× 10 g cm ⇒=x 0.5% since it is composed of 1-x=99.5% of neutrons, such star is effectively a giant atomic nucleus PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics Observing Pulsar-Type Neutron Stars Through Their Radiation NASA Chandra satelite imaging of rings created by the X-rays from a Circinus-X1 double star system, containing neutron star orbiting around another massive star, reflecting off different dust clouds PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics Quark Deconfinement in High-Density Matter Neutron Star n→+2 duneutron density > 10 x 0.15 fm-3 µn=2 µµ du + chemical equilibrium 21 1 A Lett. Phys. Mod. nn− =⇒=0 n ncharge conserved 33ud u 2 d pressure equilibrium PPPn= du + At the density and pressure at which a neutron–quark phase transition is expected to occur, the system of neutrons is not ideal degenerate Fermi gas 29 , 1430022 (2014) PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics Quark Matter Core in Massive Neutron Stars from Gravitational Waves Observed by LIGO + QCD Calculations PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics Insufficient Pressure → Black Holes and Their Thermodynamics 2 photon of energy ε cannot ≈= ε cM escape the surface of the star R0 3 km for MM ε −≤G 0 to reach an observer c 2GM R0 = Schwarzschild R0 2 radius factor 2 comes from general relativity which must be used when c gravitation potential energy is comparable to other energies 2 11∂∂S kc3 2GM 8π kG 3 = = BBπ = 24 23M kcB Bekenstein-Hawking T∂∂ EcM4 G c c SA= entropy of a black hole 4G M T = 6.169 × 10−8 K M HAWKING RADIATION: Particle-antiparticle pairs created from vacuum normally quickly annihilate each other, but near the horizon of a black hole, it's possible for one to fall in before the annihilation can happen, in which case the other one escapes as Hawking radiation 4 1 ∂E d π 24k 16πGc231 =−⇒σ 42 =− B T( Mc ) 32 4 Hawking radiation evaporates black hole A∂ t dt 60 c c8π kB G M 4 2 dM c 3 1/3 74 M =− ≡−b ⇒ M( t ) = ( M − 3 bt ) → 0 after τ ≈2.2 × 10 s much longer than the age of dt15360 G2 the Universe ~1018 s PHYS813: Quantum Statistical Mechanics QSM for Stellar Astrophysics.
Load more

Recommended publications
  • Astronomy 241: Foundations of Astrophysics I. the Solar System
    Astronomy 241: Foundations of Astrophysics I. The Solar System Astronomy 241 is the first part of a year-long Prerequisites: Physics 170, Physics 272 introduction to astrophysics. It uses basic (or concurrent), and Math 242 or 252A. classical mechanics and thermodynamics to Contact: Professor Joshua Barnes analyze the structure and evolution of the ([email protected]; 956-8138) Solar System. www.ifa.hawaii.edu/~barnes/ast241 Tuesday, August 21, 2012 Astrophysics BS Degree Proposal in ASTR PHYS MATH CHEM preparation FALL 241 251A 161, 171 or 181 year 1 161L, 171L, or 181L SPRING 170 242 252A 162 year 1 170L 162L Foundations of Astrophysics I: FALL 241 272 243 253A The Solar System year 2 272L Foundations of Astrophysics II: SPRING 242 274 244 Galaxies & Stars year 2 274L Observational Astronomy & FALL 300 310 311 (or 307?) Laboratory year 3 300L 350 SPRING 301 311 Observational Project year 3 450 FALL 423 480 Stellar Astrophysics year 4 495 SPRING 496 481 Senior Project I, II year4 485 1 of: ASTR 320, 426, or 430 Tuesday, August 21, 2012 Units Text uses MKS units (meter, kilo-gram, second); e.g. G ≃ 6.674 × 10-11 m3 kg-1 s-2 (gravitational constant). Astronomers also use non-standard units: AU ≃ 1.496 × 1011 m (“average” Earth-Sun distance) 30 M⊙ ≃ 1.989 × 10 kg (Sun’s mass) yr ≃ 3.156 × 107 s (Earth’s orbital period) Tuesday, August 21, 2012 Order of Magnitude & Dimensional Analysis: An Example Given that Jupiter’s average density is slightly greater than water, estimate the orbital period of a satellite circling just above the planet.
    [Show full text]
  • European Astroparticle Physics Strategy 2017-2026 Astroparticle Physics European Consortium
    European Astroparticle Physics Strategy 2017-2026 Astroparticle Physics European Consortium August 2017 European Astroparticle Physics Strategy 2017-2026 www.appec.org Executive Summary Astroparticle physics is the fascinating field of research long-standing mysteries such as the true nature of Dark at the intersection of astronomy, particle physics and Matter and Dark Energy, the intricacies of neutrinos cosmology. It simultaneously addresses challenging and the occurrence (or non-occurrence) of proton questions relating to the micro-cosmos (the world decay. of elementary particles and their fundamental interactions) and the macro-cosmos (the world of The field of astroparticle physics has quickly celestial objects and their evolution) and, as a result, established itself as an extremely successful endeavour. is well-placed to advance our understanding of the Since 2001 four Nobel Prizes (2002, 2006, 2011 and Universe beyond the Standard Model of particle physics 2015) have been awarded to astroparticle physics and and the Big Bang Model of cosmology. the recent – revolutionary – first direct detections of gravitational waves is literally opening an entirely new One of its paths is targeted at a better understanding and exhilarating window onto our Universe. We look of cataclysmic events such as: supernovas – the titanic forward to an equally exciting and productive future. explosions marking the final evolutionary stage of massive stars; mergers of multi-solar-mass black-hole Many of the next generation of astroparticle physics or neutron-star binaries; and, most compelling of all, research infrastructures require substantial capital the violent birth and subsequent evolution of our infant investment and, for Europe to remain competitive Universe.
    [Show full text]
  • An Overview of New Worlds, New Horizons in Astronomy and Astrophysics About the National Academies
    2020 VISION An Overview of New Worlds, New Horizons in Astronomy and Astrophysics About the National Academies The National Academies—comprising the National Academy of Sciences, the National Academy of Engineering, the Institute of Medicine, and the National Research Council—work together to enlist the nation’s top scientists, engineers, health professionals, and other experts to study specific issues in science, technology, and medicine that underlie many questions of national importance. The results of their deliberations have inspired some of the nation’s most significant and lasting efforts to improve the health, education, and welfare of the United States and have provided independent advice on issues that affect people’s lives worldwide. To learn more about the Academies’ activities, check the website at www.nationalacademies.org. Copyright 2011 by the National Academy of Sciences. All rights reserved. Printed in the United States of America This study was supported by Contract NNX08AN97G between the National Academy of Sciences and the National Aeronautics and Space Administration, Contract AST-0743899 between the National Academy of Sciences and the National Science Foundation, and Contract DE-FG02-08ER41542 between the National Academy of Sciences and the U.S. Department of Energy. Support for this study was also provided by the Vesto Slipher Fund. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the agencies that provided support for the project. 2020 VISION An Overview of New Worlds, New Horizons in Astronomy and Astrophysics Committee for a Decadal Survey of Astronomy and Astrophysics ROGER D.
    [Show full text]
  • Astrophysique / Astrophysics- Bibliographie De Pierre Léna
    Astrophysique/Astrophysics Revues avec relecteurs/Journals with referees Références [1] P. Léna. Adaptive optics : a breakthrough in astronomy. Experimental Astro- nomy, 26 :35–48, August 2009. [2] Y. Clénet, D. Rouan, P. Léna, E. Gendron, and F. Lacombe. The Galactic Centre at infrared wavelengths : towards the highest spatial resolution. Comptes Rendus Physique, 8 :26–34, January 2007. [3] G. Perrin, J. Woillez, O. Lai, J. Guérin, T. Kotani, P. L. Wizinowich, D. Le Mignant, M. Hrynevych, J. Gathright, P. Léna, F. Chaffee, S. Vergnole, L. De- lage, F. Reynaud, A. J. Adamson, C. Berthod, B. Brient, C. Collin, J. Créte- net, F. Dauny, C. Deléglise, P. Fédou, T. Goeltzenlichter, O. Guyon, R. Hulin, C. Marlot, M. Marteaud, B.-T. Melse, J. Nishikawa, J.-M. Reess, S. T. Ridgway, F. Rigaut, K. Roth, A. T. Tokunaga, and D. Ziegler. Interferometric coupling of the Keck telescopes with single-mode fibers. Science, 311 :194, January 2006. [4] Y. Clénet, D. Rouan, D. Gratadour, P. Léna, and O. Marco. The infrared emission of the dust clouds close to Sgr A*. Journal of Physics Conference Series, 54 :386–390, December 2006. [5] Y. Clénet, D. Rouan, D. Gratadour, O. Marco, P. Léna, N. Ageorges, and E. Gendron. A dual emission mechanism in Sgr A* ar L’ band. A&A, 439 :L9– L13, August 2005. [6] P. Léna. Astronomie et optique : un couple heureux. Journal de Physique IV, 119 :51–56, November 2004. [7] M. Glanc, E. Gendron, D. Lafaille, J.-F. Le Gargasson, and P. Léna. Towards wide-field retinal imaging with adaptive optics. Optics Communications, pages 225–238, 2004.
    [Show full text]
  • A History of Astronomy, Astrophysics and Cosmology - Malcolm Longair
    ASTRONOMY AND ASTROPHYSICS - A History of Astronomy, Astrophysics and Cosmology - Malcolm Longair A HISTORY OF ASTRONOMY, ASTROPHYSICS AND COSMOLOGY Malcolm Longair Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE Keywords: History, Astronomy, Astrophysics, Cosmology, Telescopes, Astronomical Technology, Electromagnetic Spectrum, Ancient Astronomy, Copernican Revolution, Stars and Stellar Evolution, Interstellar Medium, Galaxies, Clusters of Galaxies, Large- scale Structure of the Universe, Active Galaxies, General Relativity, Black Holes, Classical Cosmology, Cosmological Models, Cosmological Evolution, Origin of Galaxies, Very Early Universe Contents 1. Introduction 2. Prehistoric, Ancient and Mediaeval Astronomy up to the Time of Copernicus 3. The Copernican, Galilean and Newtonian Revolutions 4. From Astronomy to Astrophysics – the Development of Astronomical Techniques in the 19th Century 5. The Classification of the Stars – the Harvard Spectral Sequence 6. Stellar Structure and Evolution to 1939 7. The Galaxy and the Nature of the Spiral Nebulae 8. The Origins of Astrophysical Cosmology – Einstein, Friedman, Hubble, Lemaître, Eddington 9. The Opening Up of the Electromagnetic Spectrum and the New Astronomies 10. Stellar Evolution after 1945 11. The Interstellar Medium 12. Galaxies, Clusters Of Galaxies and the Large Scale Structure of the Universe 13. Active Galaxies, General Relativity and Black Holes 14. Classical Cosmology since 1945 15. The Evolution of Galaxies and Active Galaxies with Cosmic Epoch 16. The Origin of Galaxies and the Large-Scale Structure of The Universe 17. The VeryUNESCO Early Universe – EOLSS Acknowledgements Glossary Bibliography Biographical SketchSAMPLE CHAPTERS Summary This chapter describes the history of the development of astronomy, astrophysics and cosmology from the earliest times to the first decade of the 21st century.
    [Show full text]
  • Astronomy, Astrophysics, and Cosmology
    Astronomy, Astrophysics, and Cosmology Luis A. Anchordoqui Department of Physics and Astronomy Lehman College, City University of New York Lesson VI March 15, 2016 arXiv:0706.1988 L. A. Anchordoqui (CUNY) Astronomy, Astrophysics, and Cosmology 3-15-2016 1 / 26 L. A. Anchordoqui (CUNY) Astronomy, Astrophysics, and Cosmology 3-15-2016 2 / 26 Table of Contents 1 Expansion of the Universe Friedmann-Robertson-Walker cosmologies L. A. Anchordoqui (CUNY) Astronomy, Astrophysics, and Cosmology 3-15-2016 3 / 26 Expansion of the Universe Friedmann-Robertson-Walker cosmologies In 1917 Einstein presented model of universe which describing geometrically symmetric (spherical) space with finite volume but no boundary In accordance with Cosmological Principle model is homogeneous and isotropic It is also static + volume of space does not change To obtain static model Einstein introduced new repulsive force in his equations Size of this cosmological term is given by L Einstein presented model before redshifts of galaxies were known taking universe to be static was then reasonable When expansion of universe was discovered argument in favor of cosmological constant vanished Most recent observations seem to indicate that non-zero L has to be present L. A. Anchordoqui (CUNY) Astronomy, Astrophysics, and Cosmology 3-15-2016 4 / 26 22 CHAPTER 16 COSMOLOGY EXAMPLE 16.2 Critical Density of the Universe We can estimate the critical mass density of the Universe, Using H ϭ 23 ϫ 10Ϫ3 m/(s · lightyear), where 1 light- 15 Ϫ11 2 2 ␳c, using classical energy considerations. The result turns year ϭ 9.46 ϫ 10 m and G ϭ 6.67 ϫ 10 N · m /kg , out to be in agreement with the rigorous predictions of yields a present value of the critical density ␳c ϭ 1.1 ϫ general relativity because of the simplifying assumption 10Ϫ26 kg/m3.
    [Show full text]
  • Quantum Vacuum Energy and the Emergence of Gravity an Essay
    Applied Physics Research; Vol. 10, No. 2; 2018 ISSN 1916-9639 E-ISSN 1916-9647 Published by Canadian Center of Science and Education Quantum Vacuum Energy and the Emergence of Gravity An Essay Philip J. Tattersall1 1 Private researcher, 8 Lenborough St, Beauty Point, Tasmania, Australia. Correspondence: Philip J. Tattersall, 8 Lenborough St, Beauty Point, Tasmania, Australia. E-mail: [email protected] Received: December 19, 2017 Accepted: January 26, 2018 Online Published: February 28, 2018 doi:10.5539/apr.v10n2p1 URL: https://doi.org/10.5539/apr.v10n2p1 Abstract Building on the work of others a novel idea is put forward regarding the possible mechanism of gravity as involving energy coupling down the energy gradient of a massive body. Free fall (acceleration) in a gravitational field is explained as arising from an interaction of the modified quantum vacuum energy in the vicinity of matter. Key words: Gravity, quantum vacuum, zero-point energy, electromagnetic energy, inertia, acceleration, free fall, gravitational energy gradient, non-gravitational acceleration 1. Introduction There has been a great deal of activity, both in terms of theoretical and experimental work exploring the possible link between quantum vacuum energy and gravity. Over the years quantum vacuum energy has become synonymous with zero-point energy (ZPE), and so this term will be used interchangeably throughout this paper. The nature of ZPE has been the subject of intense interest (Santos, 2012; Margan, nd (a&b); Rueda & Haisch, 2005; Puthoff, 2001). It was Sakharov (1967) who reached the conclusion that matter somehow induced certain changes in the quantum vacuum and that these changes might explain a number of phenomena including the Casimir effect.
    [Show full text]
  • Zero-Point Energy of Vacuum Fluctuation As a Candidate
    Zero-point energy of vacuum fluctuation as a candidate for dark energy versus a new conjecture of antigravity based on the modified Einstein field equation in general relativity Guang-jiong Ni Department of Physics, Fudan University, Shanghai, 200433, China Department of Physics, Portland State University, Portland, OR97207, U.S.A. Email address: [email protected] In order to clarify why the zero-point energy associated with the vacuum fluctuations cannot be a candidate for the dark energy in the universe, a comparison with the Casimir effect is analyzed in some detail. A principle of epistemology is stressed that it is meaningless to talk about an absolute (isolated) thing. A relative thing can only be observed when it is changing with respect to other things. Then a new conjecture of antigravity — the repulsive force between matter and antimatter derived from the modified Einstein field equation in general relativity — is proposed. This is due to the particle – antiparticle symmetry based on a new understanding about the essence of special relativity. Its possible consequences in the theory of cosmology are discussed briefly, including a new explanation for the accelerating universe and gamma-ray bursts. I. INTRODUCTION The past decade has witnessed a remarkable progress of cosmology and astrophysics. Especially, the precise data provided by the Hubble Space Telescope (HST) key project, the Wilkinson Microwave Anisotropy Probe (WMAP) team, the Sloan Digital Sky Survey (SDSS) and the discovery of acceleration of the universe expansion, etc. have shaped an observable universe quite quantitatively. The present understanding can be summarized basically as follows (see, e.g.
    [Show full text]
  • The Quantum Vacuum and the Cosmological Constant Problem
    The Quantum Vacuum and the Cosmological Constant Problem S.E. Rugh∗and H. Zinkernagely To appear in Studies in History and Philosophy of Modern Physics Abstract - The cosmological constant problem arises at the intersection be- tween general relativity and quantum field theory, and is regarded as a fun- damental problem in modern physics. In this paper we describe the historical and conceptual origin of the cosmological constant problem which is intimately connected to the vacuum concept in quantum field theory. We critically dis- cuss how the problem rests on the notion of physically real vacuum energy, and which relations between general relativity and quantum field theory are assumed in order to make the problem well-defined. 1. Introduction Is empty space really empty? In the quantum field theories (QFT’s) which underlie modern particle physics, the notion of empty space has been replaced with that of a vacuum state, defined to be the ground (lowest energy density) state of a collection of quantum fields. A peculiar and truly quantum mechanical feature of the quantum fields is that they exhibit zero-point fluctuations everywhere in space, even in regions which are otherwise ‘empty’ (i.e. devoid of matter and radiation). These zero-point fluctuations of the quantum fields, as well as other ‘vacuum phenomena’ of quantum field theory, give rise to an enormous vacuum energy density ρvac. As we shall see, this vacuum energy density is believed to act as a contribution to the cosmological constant Λ appearing in Einstein’s field equations from 1917, 1 8πG R g R Λg = T (1) µν − 2 µν − µν c4 µν where Rµν and R refer to the curvature of spacetime, gµν is the metric, Tµν the energy-momentum tensor, G the gravitational constant, and c the speed of light.
    [Show full text]
  • The Sun As a Guide to Stellar Physics This Page Intentionally Left Blank the Sun As a Guide to Stellar Physics
    The Sun as a Guide to Stellar Physics This page intentionally left blank The Sun as a Guide to Stellar Physics Edited by Oddbjørn Engvold Professor emeritus, Rosseland Centre for Solar Physics, Institute of Theoretical Astrophysics, University of Oslo, Oslo, Norway Jean-Claude Vial Emeritus Senior Scientist, Institut d’Astrophysique Spatiale, CNRS-Universite´ Paris-Sud, Orsay, France Andrew Skumanich Emeritus Senior Scientist, High Altitude Observatory, National Center for Atmospheric Research, Boulder, Colorado, United States Elsevier Radarweg 29, PO Box 211, 1000 AE Amsterdam, Netherlands The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, United Kingdom 50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States Copyright © 2019 Elsevier Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein.
    [Show full text]
  • A Astronomical Terminology
    A Astronomical Terminology A:1 Introduction When we discover a new type of astronomical entity on an optical image of the sky or in a radio-astronomical record, we refer to it as a new object. It need not be a star. It might be a galaxy, a planet, or perhaps a cloud of interstellar matter. The word “object” is convenient because it allows us to discuss the entity before its true character is established. Astronomy seeks to provide an accurate description of all natural objects beyond the Earth’s atmosphere. From time to time the brightness of an object may change, or its color might become altered, or else it might go through some other kind of transition. We then talk about the occurrence of an event. Astrophysics attempts to explain the sequence of events that mark the evolution of astronomical objects. A great variety of different objects populate the Universe. Three of these concern us most immediately in everyday life: the Sun that lights our atmosphere during the day and establishes the moderate temperatures needed for the existence of life, the Earth that forms our habitat, and the Moon that occasionally lights the night sky. Fainter, but far more numerous, are the stars that we can only see after the Sun has set. The objects nearest to us in space comprise the Solar System. They form a grav- itationally bound group orbiting a common center of mass. The Sun is the one star that we can study in great detail and at close range. Ultimately it may reveal pre- cisely what nuclear processes take place in its center and just how a star derives its energy.
    [Show full text]
  • BS Physics Concentration Astrophysics
    CLARION UNIVERSITY OF PENNSYLVANIA DEGREE: B.S. Physics College of Arts and Sciences Concentration in Astrophysics Name Transfer:*______________________________________________ Clarion ID **_____________________________________________ Entrance Date CUP: _____ _____ _____ _____ _____ _____ _____ Program Entry Date____________________________ _____ _____ _____ _____ _____ _____ _____ _____ Advisor _____ _____ _____ _____ _____ _____ _____ _____ *********************************************************************************************************************************************** GENERAL EDUCATION REQUIREMENTS – 48 CREDITS Please refer to the approved list of Gen Ed courses that appears in the published class schedule. V. REQUIREMENTS IN MAJOR: (70 – 72 credits) CR. GR I. LIBERAL EDUCATION SKILLS – 12 CREDITS CR. GR. A. REQUIRED IN PHYSICS (38-39 credits) A. English Composition (3 credits) 1 PH 258: Introductory Physics I (Lec) 3 ___ Eng 110: Writing II 3 PH 268: Introductory Physics I (Lab) 1 ___ Eng 111: Writing II 3 PH 259: Introductory Physics II (Lec) 3 ___ B. Mathematics Competency (3 credits) PH 269: Introductory Physics II (Lab) 1 ___ : PH 301: Astrophysics I 3 ___ C. Freshman Inquiry Seminar (3 credits) PH 302: Astrophysics II 3 ___ INQ : PH 351: Mechanics: Dynamics 3 ___ PH 352: Electricity & Magnetism 3 ___ D. Credits to total 12 in Category I, selected from two of the PH 353: Modern Physics I 3 ___ following: Academic Enrichment, Communication, Computer PH 354: Optics 3 ___ Information Science, Elementary Foreign Language, English PH 355: Modern Physics II 3 ___ Composition, HON 128 Logic, Mathematics, and Speech PH 356: Thermodynamics 3 ___ Communication. PH 371: Experimental Physics I 3 ___ : PH 461: Seminar 1 ___ : PH ___: * 2-3 ___ * To be selected from 300-level and 400-level physics courses or ES 310.
    [Show full text]