DOCSLIB.ORG

Asymptotic Accuracy of the Equilibrium Diffusion Approximation and Semi-Analytic Solutions of Radiating Shocks

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Asymptotic Accuracy of the Equilibrium Diffusion Approximation and Semi-Analytic Solutions of Radiating Shocks ASYMPTOTIC ACCURACY OF THE EQUILIBRIUM DIFFUSION APPROXIMATION AND SEMI-ANALYTIC SOLUTIONS OF RADIATING SHOCKS A Dissertation by JIM MICHAEL FERGUSON Submitted to the Office of Graduate and Professional Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Chair of Committee, George Kattawar Co-Chair of Committee, Jim Morel Committee Members, Vitaly Kocharovsky Marv Adams Alexey Zheltikov Head of Department, George Welch May 2014 Major Subject: Applied Physics Copyright 2014 Jim Michael Ferguson ABSTRACT Radiation hydrodynamics (RH) provides a theoretical description for many astro- physical events spanning a wide range of observable phenomena. It is the goal of high-energy-density laboratory astrophysics (HEDLA) to reproduce some of these events in terrestrial settings. Computational models exist to aide our understanding by simulating astrophysical observations and laboratory experiments, and by mak- ing predictions which guide both experiments and observations. It is the goal of this dissertation to contribute to our understanding of computational models in RH. Two problems are solved that aide this understanding: 1) we showed that the asymptotic equilibrium diffusion limit (EDL) of the RH equations reproduces the equilibrium diffusion approximation (EDA), through first-order in the asymptotic expansion, in agreement with previous transport models that neglect material motion; and, 2) we produced semi-analytic radiative shock solutions using grey, angularly discretized (Sn) transport. The first problem establishes the asymptotic limits of the EDA in RH, which will have direct applications to discretizations of RH models. The second problem extends previous semi-analytic solution methods for radiative shocks to in- clude grey Sn transport. Previous semi-analytic methods relied on nonequilibrium diffusion theory to describe the radiation, which assumes that while the radiation is out of equilibrium with the material, the angular dependence of the radiation field is isotropic over the extended spatial domain of the radiative shock, and that the radiation energy density is monotonic over the shock's spatial domain. The purpose of using grey Sn transport is to determine the angular dependence of the radiation field. It is shown that the anisotropy of the radiation field can cause the radiation energy density to be nonmonotonic and exhibit a local maximum if a spike in the ii material temperature, called a Zel'dovich spike, near the shock discontinuity exists. This local maximum of the radiation energy density is termed \anti-diffusive" ra- diation because the radiation flux and the gradient of the radiation energy density may have the same sign in this region, which is in stark contrast to diffusion theory wherein the radiation flux is proportional to the negative gradient of the radiation energy density. iii DEDICATION This thesis is dedicated to my wife, Kimberly Rae Ferguson. You have been my constant champion, and every aspect of my life is better because you are in it. You are the wife of my youth, and I love You! iv ACKNOWLEDGEMENTS This dissertation is the end-product, over many years, and with the help of many different people, of a single pursuit: a Ph.D. in the applied sciences. Jon Hartgraves and Gaye-Lynn Seawright personally ensured that I received the best education they could provide, and just as importantly, they provided patient support and encouragement when I was still a child. Gaye-Lynn and Jimmy have provided an anchor to my past that is invaluable, and I cannot sufficiently express my gratitude. Christine Ehlig-Economides has become a true friend, and I am grateful for ev- erything that she has taken the time to teach me. Bruce Freeman introduced me to research, and true scientific curiousity. He was the first to teach me that saying \I don't know", can be the right answer. Jim Morel taught me to learn what \I don't know" before I got to his office. He has had the largest affect on how I think about physics, always pushing me to understand the de- tails, and their consequences. George Kattawar showed me a quiet forcefulness that impressed on me how much power can be wielded by silent contemplation. While George has retired, Marv Adams similarly shows all of his students this same quiet forcefulness. I am humbled, and grateful, to have been guided by these men along my scientific path. My committee has been exceedingly patient and helpful: George, Jim, Marv, Vi- v taly, and Alexey, thank you for your support and patience! Rob Lowrie, Bryan Johnson, and Nick Gentile made various contributions to the work in this dissertation, and my understanding. I look forward to continuing our collaborations. I have enjoyed many day-to-day conversations, and sundry distractions, with friends and colleagues alike. Jason Cezeaux, Erich Fruchtnicht, and Brent Lindeburg knew me before I knew myself. Jianwei Mei and Chris Bertinato helped me learn every- thing I needed to know about black-holes, and high-energy theoretical physics: That studying these subjects wouldn't allow me to support a family! Adam \Eeyore" Hetzler, Hayes Stripling, Jarrod Edwards, and Paul and Jenny Bruillard have gone before me; Don Bruss, Marco Delchini, Akansha Kumar, Alex Long, Peter Maginot, Carolyn McGraw, Andrew Till, I look forward to seeing you finish. I am grateful for these relationships! My wife has shown me exceeding patience and support; I'm still trying to learn. Ken and LouEllen have been similarly patient, and have provided me with many examples I didn't have before. I have learned, and will continue to learn, from you both, the most important lessons in life. My sweet Evelyn Grace will no longer ap- preciate being called \baby-girl" long before she can understand the words written here. You are a Blessing, and I give thanks to my God every time I think of you. vi TABLE OF CONTENTS Page ABSTRACT . ii DEDICATION . iv ACKNOWLEDGEMENTS . v TABLE OF CONTENTS . vii LIST OF FIGURES . x CHAPTER I INTRODUCTION . 1 I.1 Background . 3 I.2 Equilibrium diffusion in radiation hydrodynamics . 5 I.3 Radiative shocks . 7 I.4 State-of-the-art computational methods . 10 CHAPTER II RADIATION TRANSPORT AND RADIATION HYDRODY- NAMICS . 12 II.1 Radiation transport without material motion . 15 II.1.1 The P1 approximation . 16 II.1.2 The diffusion approximation . 19 II.1.3 The equilibrium diffusion approximation . 20 II.2 Invariants and transformations . 20 II.3 Radiation transport in the lab-frame with material motion . 23 II.4 Radiation hydrodynamics . 25 CHAPTER III ASYMPTOTIC ACCURACY OF THE EQUILIBRIUM DIF- FUSION APPROXIMATION IN RADIATION HYDRODY- NAMICS . 27 III.1 Example: asymptotic analysis of the neutron transport equation . 27 III.2 Nondimensional variables and scaling ratios . 37 III.3 Asymptotic expansion of the radiation hydrodynamic equations . 40 III.4 P1 and diffusion models in the lab- and comoving-frames in the equi- librium diffusion limit . 45 III.4.1 The comoving- and lab-frame P1 models . 48 vii Page III.4.2 The comoving- and lab-frame grey-diffusion models . 52 CHAPTER IV PREVIOUS ANALYTIC AND SEMI-ANALYTIC RADIA- TIVE SHOCK SOLUTIONS . 59 IV.1 Nonequilibrium diffusion analytic results . 60 IV.1.1 Derivation of the nonequilibrium diffusion equations . 61 IV.1.2 Subcritical radiating shocks . 65 IV.1.3 Supercritical radiating shocks . 70 IV.2 Analytic work of Drake, and McClarren and Drake . 74 IV.2.1 The three-layer model . 75 IV.2.2 Anti-diffusive radiative shocks . 81 IV.3 Previous semi-analytic solutions and code-verification . 85 IV.3.1 Review of work before 2007 . 85 IV.3.2 Semi-analytic solutions by Lowrie and collaborators . 86 IV.3.3 Code-verification of KULL's Implicit Monte Carlo radiation transport package using Lowrie's semi-analytic solutions . 97 CHAPTER V RADIATIVE SHOCK SOLUTIONS WITH GREY SN TRANS- PORT . 100 V.1 Governing equations and nondimensionalization . 103 V.2 Problem statement . 109 V.3 Reduced equations . 110 V.3.1 The ordinary differential equations for the radiation hydrody- namic solve . 111 V.3.2 The ordinary differential equations for the radiation transport solve . 114 V.4 Solution procedure . 115 V.4.1 The Rankine-Hugoniot jump conditions . 116 V.4.2 The radiation hydrodynamic solve . 116 V.4.3 The radiation transport solve . 119 V.5 Results and analysis . 120 V.5.1 Comparison of nonequilibrium diffusion and Sn radiative shock solutions . 121 V.5.2 Code-verification of KULL's Implicit Monte Carlo radiation transport package using grey Sn transport . 124 V.5.3 Comparison of the material and radiative temperatures near the embedded hydrodynamic shock to the final temperature and anti-diffusive radiation . 131 viii Page V.5.4 Onset of supercritical shocks . 135 CHAPTER VI SUMMARY . 137 REFERENCES . 141 APPENDIX A DERIVATION OF THE FOUR LORENTZ INVARIANTS . 147 APPENDIX B DERIVATION OF THE TRANSFORMED IN-SCATTER SOURCE . 152 APPENDIX C DERIVATION OF THE LAB-FRAME RADIATION TRANS- PORT EQUATION THROUGH O(β2) . 154 APPENDIX D ASYMPTOTIC DERIVATION OF THE RADIATION VARI- ABLES THROUGH O(2) . 162 APPENDIX E DERIVATION OF THE O(β2) CORRECTIONS TO THE RADIATION TRANSPORT EQUATION . 169 APPENDIX F DERIVATION OF THE WAVE EQUATION AND NONDI- MENSIONALIZATION OF THE IDEAL GAS EQUATION OF STATE . 173 APPENDIX G DERIVATION OF THE LINEARIZATION PROCEDURE USED FOR THE RADIATION HYDRODYNAMIC SOLVE IN THE FIRST ITERATION . 180 ix LIST OF FIGURES Page Figure I.1 Simeis 147, the remnant of SN185. A neutron star is in the center of the figure. The red filaments represent color enhancement of hydrogen recombination at the front of the expanding shock. Adapted from the March 24, 2005, Astronomy Picture of the Day [16]. 7 Figure I.2 SN1987A was viewed from earth on February 23, 1987. Only 168,000 light-years away, it is one of the most well-studied super- novae.
Load more

Recommended publications
  • SHAPING the WIND of DYING STARS Noam Soker
    Pleasantness Review* Department of Physics, Technion, Israel The role of jets in the common envelope evolution (CEE) and in the grazing envelope evolution (GEE) Cambridge 2016 Noam Soker •Dictionary translation of my name from Hebrew to English (real!): Noam = Pleasantness Soker = Review A short summary JETS See review accepted for publication by astro-ph in May 2016: Soker, N., 2016, arXiv: 160502672 A very short summary JFM See review accepted for publication by astro-ph in May 2016: Soker, N., 2016, arXiv: 160502672 A full summary • Jets are unavoidable when the companion enters the common envelope. They are most likely to continue as the secondary star enters the envelop, and operate under a negative feedback mechanism (the Jet Feedback Mechanism - JFM). • Jets: Can be launched outside and Secondary inside the envelope star RGB, AGB, Red Giant Massive giant primary star Jets Jets Jets: And on its surface Secondary star RGB, AGB, Red Giant Massive giant primary star Jets A full summary • Jets are unavoidable when the companion enters the common envelope. They are most likely to continue as the secondary star enters the envelop, and operate under a negative feedback mechanism (the Jet Feedback Mechanism - JFM). • When the jets mange to eject the envelope outside the orbit of the secondary star, the system avoids a common envelope evolution (CEE). This is the Grazing Envelope Evolution (GEE). Points to consider (P1) The JFM (jet feedback mechanism) is a negative feedback cycle. But there is a positive ingredient ! In the common envelope evolution (CEE) more mass is removed from zones outside the orbit.
    [Show full text]
  • Features in Cosmic-Ray Lepton Data Unveil the Properties of Nearby Cosmic Accelerators
    Prepared for submission to JCAP Features in cosmic-ray lepton data unveil the properties of nearby cosmic accelerators O. Fornieri,a;b;d;1 D. Gaggerod and D. Grassob;c aDipartimento di Scienze Fisiche, della Terra e dell'Ambiente, Universit`adi Siena, Via Roma 56, 53100 Siena, Italy bINFN Sezione di Pisa, Polo Fibonacci, Largo B. Pontecorvo 3, 56127 Pisa, Italy cDipartimento di Fisica, Universit`adi Pisa, Polo Fibonacci, Largo B. Pontecorvo 3 dInstituto de F´ısicaTe´oricaUAM-CSIC, Campus de Cantoblanco, E-28049 Madrid, Spain E-mail: [email protected], [email protected], [email protected] Abstract. We present a comprehensive discussion about the origin of the features in the leptonic component of the cosmic-ray spectrum. Working in the framework of a up-to-date CR transport scenario tuned on the most recent AMS-02 and Voyager data, we show that the prominent features recently found in the positron and in the all-electron spectra by several experiments are compatible with a scenario in which pulsar wind nebulae (PWNe) are the dominant sources of the positron flux, and nearby supernova remnants (SNRs) shape the high-energy peak of the electron spectrum. In particular we argue that the drop-off in positron spectrum found by AMS-02 at 300 GeV can be explained | under different ∼ assumptions | in terms of a prominent PWN that provides the bulk of the observed positrons in the 100 GeV domain, on top of the contribution from a large number of older objects. ∼ Finally, we turn our attention to the spectral softening at 1 TeV in the all-lepton spectrum, ∼ recently reported by several experiments, showing that it requires the presence of a nearby arXiv:1907.03696v2 [astro-ph.HE] 6 Mar 2020 supernova remnant at its final stage.
    [Show full text]
  • Supernova Environmental Impacts
    Proceedings of the International Astronomical Union IAU Symposium No. 296 IAU Symposium IAU Symposium 7–11 January 2013 New telescopes spanning the full electromagnetic spectrum have enabled the study of supernovae (SNe) and supernova remnants 296 Raichak on Ganges, (SNRs) to advance at a breath-taking pace. Automated synoptic Calcutta, India surveys have increased the detection rate of supernovae by more than an order of magnitude and have led to the discovery of highly unusual supernovae. Observations of gamma-ray emission from 7–11 January 296 7–11 January 2013 Supernova SNRs with ground-based Cherenkov telescopes and the Fermi 2013 Supernova telescope have spawned new insights into particle acceleration in Raichak on Ganges, supernova shocks. Far-infrared observations from the Spitzer and Raichak Environmental Herschel observatories have told us much about the properties on Ganges, Calcutta, India Environmental and fate of dust grains in SNe and SNRs. Work with satellite-borne Calcutta, India Chandra and XMM-Newton telescopes and ground-based radio Impacts and optical telescopes reveal signatures of supernova interaction with their surrounding medium, their progenitor life history and of Impacts the ecosystems of their host galaxies. IAU Symposium 296 covers all these advances, focusing on the interactions of supernovae with their environments. Proceedings of the International Astronomical Union Editor in Chief: Prof. Thierry Montmerle This series contains the proceedings of major scientifi c meetings held by the International Astronomical Union. Each volume contains a series of articles on a topic of current interest in Supernova astronomy, giving a timely overview of research in the fi eld. With contributions by leading scientists, these books are at a level Environmental Edited by suitable for research astronomers and graduate students.
    [Show full text]
  • List of Bright Nebulae Primary I.D. Alternate I.D. Nickname
    List of Bright Nebulae Alternate Primary I.D. Nickname I.D. NGC 281 IC 1590 Pac Man Neb LBN 619 Sh 2-183 IC 59, IC 63 Sh2-285 Gamma Cas Nebula Sh 2-185 NGC 896 LBN 645 IC 1795, IC 1805 Melotte 15 Heart Nebula IC 848 Soul Nebula/Baby Nebula vdB14 BD+59 660 NGC 1333 Embryo Neb vdB15 BD+58 607 GK-N1901 MCG+7-8-22 Nova Persei 1901 DG 19 IC 348 LBN 758 vdB 20 Electra Neb. vdB21 BD+23 516 Maia Nebula vdB22 BD+23 522 Merope Neb. vdB23 BD+23 541 Alcyone Neb. IC 353 NGC 1499 California Nebula NGC 1491 Fossil Footprint Neb IC 360 LBN 786 NGC 1554-55 Hind’s Nebula -Struve’s Lost Nebula LBN 896 Sh 2-210 NGC 1579 Northern Trifid Nebula NGC 1624 G156.2+05.7 G160.9+02.6 IC 2118 Witch Head Nebula LBN 991 LBN 945 IC 405 Caldwell 31 Flaming Star Nebula NGC 1931 LBN 1001 NGC 1952 M 1 Crab Nebula Sh 2-264 Lambda Orionis N NGC 1973, 1975, Running Man Nebula 1977 NGC 1976, 1982 M 42, M 43 Orion Nebula NGC 1990 Epsilon Orionis Neb NGC 1999 Rubber Stamp Neb NGC 2070 Caldwell 103 Tarantula Nebula Sh2-240 Simeis 147 IC 425 IC 434 Horsehead Nebula (surrounds dark nebula) Sh 2-218 LBN 962 NGC 2023-24 Flame Nebula LBN 1010 NGC 2068, 2071 M 78 SH 2 276 Barnard’s Loop NGC 2149 NGC 2174 Monkey Head Nebula IC 2162 Ced 72 IC 443 LBN 844 Jellyfish Nebula Sh2-249 IC 2169 Ced 78 NGC Caldwell 49 Rosette Nebula 2237,38,39,2246 LBN 943 Sh 2-280 SNR205.6- G205.5+00.5 Monoceros Nebula 00.1 NGC 2261 Caldwell 46 Hubble’s Var.
    [Show full text]
  • Core-Collapse Supernovae Overview with Swift Collaboration
    Publications Spring 2015 Core-Collapse Supernovae Overview with Swift Collaboration Kiranjyot Gill Embry-Riddle Aeronautical University, [email protected] Michele Zanolin Embry-Riddle Aeronautical University, [email protected] Marek Szczepańczyk Embry-Riddle Aeronautical University, [email protected] Follow this and additional works at: https://commons.erau.edu/publication Part of the Astrophysics and Astronomy Commons, and the Physics Commons Scholarly Commons Citation Gill, K., Zanolin, M., & Szczepańczyk, M. (2015). Core-Collapse Supernovae Overview with Swift Collaboration. , (). Retrieved from https://commons.erau.edu/publication/3 This Report is brought to you for free and open access by Scholarly Commons. It has been accepted for inclusion in Publications by an authorized administrator of Scholarly Commons. For more information, please contact [email protected]. Core-Collapse Supernovae Overview with Swift Collaboration∗ Kiranjyot Gill,y Dr. Michele Zanolin,z and Marek Szczepanczykx Physics Department, Embry Riddle Aeronautical University (Dated: June 30, 2015) The Core-Collapse supernovae (CCSNe) mark the dynamic and explosive end of the lives of massive stars. The mysterious mechanism, primarily focused with the shock revival phase, behind CCSNe explosions could be explained by detecting the corresponding gravitational wave (GW) emissions by the laser interferometer gravitational wave observatory, LIGO. GWs are extremely hard to detect because they are weak signals in a floor of instrument noise. Optical observations of CCSNe are already used in coincidence with LIGO data, as a hint of the times where to search for the emission of GWs. More of these hints would be very helpful. For the first time in history a Harvard group has observed X-ray transients in coincidence with optical CCSNe.
    [Show full text]
  • Atlas Menor Was Objects to Slowly Change Over Time
    C h a r t Atlas Charts s O b by j Objects e c t Constellation s Objects by Number 64 Objects by Type 71 Objects by Name 76 Messier Objects 78 Caldwell Objects 81 Orion & Stars by Name 84 Lepus, circa , Brightest Stars 86 1720 , Closest Stars 87 Mythology 88 Bimonthly Sky Charts 92 Meteor Showers 105 Sun, Moon and Planets 106 Observing Considerations 113 Expanded Glossary 115 Th e 88 Constellations, plus 126 Chart Reference BACK PAGE Introduction he night sky was charted by western civilization a few thou - N 1,370 deep sky objects and 360 double stars (two stars—one sands years ago to bring order to the random splatter of stars, often orbits the other) plotted with observing information for T and in the hopes, as a piece of the puzzle, to help “understand” every object. the forces of nature. The stars and their constellations were imbued with N Inclusion of many “famous” celestial objects, even though the beliefs of those times, which have become mythology. they are beyond the reach of a 6 to 8-inch diameter telescope. The oldest known celestial atlas is in the book, Almagest , by N Expanded glossary to define and/or explain terms and Claudius Ptolemy, a Greco-Egyptian with Roman citizenship who lived concepts. in Alexandria from 90 to 160 AD. The Almagest is the earliest surviving astronomical treatise—a 600-page tome. The star charts are in tabular N Black stars on a white background, a preferred format for star form, by constellation, and the locations of the stars are described by charts.
    [Show full text]
  • POVĚTROŇ Královéhradecký Astronomický Časopis ∗ Ročník 22 ∗ Číslo 3/2014 Slovo Úvodem
    POVĚTROŇ Královéhradecký astronomický èasopis ∗ ročník 22 ∗ číslo 3/2014 Slovo úvodem. Zpoždění Povětroně 3/2014 lze vysvětlit dvěma slovy, slovem di- gitální a slovem planetárium. Jeho uvedení do provozu bylo chtě–nechtě prioritou číslo 1, jak o tom budeme psát v některém z následujících čísel. Nicméně, v tomto čísle jde zejména o dvojici èlánkù Milo¹e Boèka, které jsou věnovány superno- vám a jejich vizuálnímu pozorování. Dále Jaromír Ciesla pøipojuje vyhodnocení pravidelné ankety, a to dokonce za celý pùlrok. Miroslav Brož Obsah strana Milo¹ Boèek: Vizuálně pozorované supernovy v roce 2012 .............. 3 Milo¹ Boèek: Historicky pozorované i nepozorované supernovy v Galaxii . 14 Jaromír Ciesla: Sluneční hodiny druhého kvartálu roku 2014 . 17 Jaromír Ciesla: Sluneční hodiny tøetího kvartálu roku 2014 . 21 Titulní strana | Snímek supernovy SN 2012A z ledna 2012, pořízený na observatoøi Mount Lemmon SkyCenter Schulmanovým reflektorem (typu Ritchey{Chrétien) o průměru 0,81 m a CCD kamerou SBIG STX{16803. V pozadí na fotografii je vidno mnoho vzdálených gala- xií rùzných morfologických typù. c Adam Block, Mount Lemmon Skycenter, University of Arizona. K èlánku na str. 3. Povětroň 3/2014; Hradec Králové, 2014. Vydala: Astronomická spoleènost v Hradci Králové (7. 2. 2015 na 288. setkání ASHK) ve spolupráci s Hvězdárnou a planetáriem v Hradci Králové vydání 1., 24 stran, náklad 100 ks; dvouměsíčník, MK ÈR E 13366, ISSN 1213{659X Redakce: Miroslav Brož, Milo¹ Boèek, Martin Cholasta, Josef Kujal, Martin Lehký, Lenka Trojanová a Miroslav Ouhrabka Pøedplatné tištěné verze: vyøizuje redakce, cena 35,{ Kè za číslo (včetně po¹tovného) Adresa: ASHK, Národních mučedníků 256, Hradec Králové 8, 500 08; IÈO: 64810828 e{mail: [email protected], web: hhttp://www.ashk.czi Vizuálně pozorované supernovy v roce 2012 Milo¹ Boèek Někteří astrofyzikové uvádějí, že v pozorovatelné èásti vesmíru vybuchne a za- září jako supernovy až tøicet hvězd každou sekundu.1 V naší mateøské Galaxii bylo v¹ak dosud historicky zaznamenáno pouze sedm nebo osm takových vzplanutí (viz dodatkový èlánek).
    [Show full text]
  • Kinematics and 3D Dust Mapping of S147
    Kinematics and 3D dust mapping of S147 Speaker: Bingqiu Chen (陈丙秋, [email protected]), Peking University! Collaborators: Xiaowei Liu, Juanjuan Ren, Haibo Yuan, Yang Huang, " Maosheng Xiang, Chun Wang, et al." 2017.02.18@YNU! Summary •# We summarize the LAMOST observations in the S147 region, redo the sky subtraction, and obtain fundamental kinematic information of S147, such as –# radial velocity field, –# line width map, –# line intensity ratio map， –# expansion velocity •# We present a 3D extinction analysis in the S147 region using data from XSTPS-GAC, 2MASS and WISE and isolate a previously unrecognised dust structure likely to be associated with SNR S147,term as “S147 dust cloud”. The cloud –# have a distance d=1.22 ± 0.21 kpc, consistent with the conjecture that S147 is associated with pulsar PSR J0538+2817. –# have morphology suggesting complicate interaction between the SNR S147 and the surrounding molecular clouds. Outline •# The supernova remnant S147 •# Kinematics of S147 based on LAMOST data –# Introduction –# Observation and data reduction –# Parameter determination and analysis •# Mapping the 3D dust extinction toward S147 – the S147 dust cloud –# Introduction –# Data and method –# The S147 dust cloud •# Summary Introduction •# SNRs are beautiful astronomical objects that are of high scientific interest. –# likely sources of Galactic cosmic rays –# insights into supernova explosion mechanisms. –# distributing various elements through the ISM •# Simeis 147, Sh2-240, SNR G180.0-01.7 –# Location: α=05h39m00s, δ=+27°50'00” –# Size: ~200 arcmin (76pc) –# Age: ~30,000 yr –# Radio: Large faint shell –# Optical: Wispy ring. –# X-ray: Possible detection. –# Point sources: Pulsar within boundary, with faint wind nebula.
    [Show full text]
  • Explorethe Impact That Killed the Dinosaursp. 26
    EXPLORE the impact that killed the dinosaurs p. 26 DECEMBER 2016 The world’s best-selling astronomy magazine Understanding cannibal star systems p. 20 How moon dust will put a ring around Mars p. 46 Discover colorful star clusters p. 32 www.Astronomy.com AND MORE BONUS Vol. 44 Astronomy on Tap becomes a hit p. 58 ONLINE • CONTENT Issue 12 Meet the master of stellar vistas p. 52 CODE p. 3 iOptron’s new mount tested p. 62 ÛiÃÌÊÊÞÕÀÊiÞiÌ°°° ...and share the dividends for a lifetime. Tele Vue APO refractors earn a high yield of happy owners. 35 years of hand-building scopes with care and dedication is why we see comments like: “Thanks to all at Tele Vue for such wonderful products.” The care that goes into building every Tele Vue telescope is evident from the first time you focus an image. What goes unseen are the hours of work that led to that moment. Hand-fitted rack & pinion focusers must withstand 10lb. deflection testing along their travel, yet operate buttery-smooth, without gear lash or image TV-60 shift. Optics are fitted, spaced, and aligned using proprietary techniques to form breathtaking low-power views, spectacular high-power planetary performance, or stunning wide-field images. When you purchase a TV-76 Tele Vue telescope you’re not so much buying a telescope as acquiring a lifetime observing companion. Comments from recent warranty cards UÊ­/6Èä®ÊºÊV>ÌÊÌ >ÊÞÕÊiÕ} ÊvÀÊ«ÀÛ`}ÊiÊÜÌ ÊÃÕV ʵÕ>ÌÞtÊ/ ÃÊÃV«iÊÜÊ}ÛiÊiÊ>Êlifetime TV-85 of observing happiness.” —M.E.,Canada U­/6ÇȮʺ½ÛiÊÜ>Ìi`Ê>Ê/6ÊÃV«iÊvÀÊ{äÊÞi>ÀðÊ>ÞtÊ`]ʽÊÛiÀÜ ii`tÊLove, Love, Love Ìtt»p °°]" U­/6nx®ÊºPerfect form, perfect function, perfectÊÌiiÃV«i]Ê>`ÊÊ``½ÌÊ >ÛiÊÌÊÜ>ÌÊxÊÞi>ÀÃÊÌÊ}iÌÊÌt»p,° °]/8 U­/6nx®Êº/ >ÊÞÕÊvÀÊ>}ÊÃÕV Êbeautiful equipment available.
    [Show full text]
  • Astronomy Magazine 2012 Index Subject Index
    Astronomy Magazine 2012 Index Subject Index A AAR (Adirondack Astronomy Retreat), 2:60 AAS (American Astronomical Society), 5:17 Abell 21 (Medusa Nebula; Sharpless 2-274; PK 205+14), 10:62 Abell 33 (planetary nebula), 10:23 Abell 61 (planetary nebula), 8:72 Abell 81 (IC 1454) (planetary nebula), 12:54 Abell 222 (galaxy cluster), 11:18 Abell 223 (galaxy cluster), 11:18 Abell 520 (galaxy cluster), 10:52 ACT-CL J0102-4915 (El Gordo) (galaxy cluster), 10:33 Adirondack Astronomy Retreat (AAR), 2:60 AF (Astronomy Foundation), 1:14 AKARI infrared observatory, 3:17 The Albuquerque Astronomical Society (TAAS), 6:21 Algol (Beta Persei) (variable star), 11:14 ALMA (Atacama Large Millimeter/submillimeter Array), 2:13, 5:22 Alpha Aquilae (Altair) (star), 8:58–59 Alpha Centauri (star system), possibility of manned travel to, 7:22–27 Alpha Cygni (Deneb) (star), 8:58–59 Alpha Lyrae (Vega) (star), 8:58–59 Alpha Virginis (Spica) (star), 12:71 Altair (Alpha Aquilae) (star), 8:58–59 amateur astronomy clubs, 1:14 websites to create observing charts, 3:61–63 American Astronomical Society (AAS), 5:17 Andromeda Galaxy (M31) aging Sun-like stars in, 5:22 black hole in, 6:17 close pass by Triangulum Galaxy, 10:15 collision with Milky Way, 5:47 dwarf galaxies orbiting, 3:20 Antennae (NGC 4038 and NGC 4039) (colliding galaxies), 10:46 antihydrogen, 7:18 antimatter, energy produced when matter collides with, 3:51 Apollo missions, images taken of landing sites, 1:19 Aristarchus Crater (feature on Moon), 10:60–61 Armstrong, Neil, 12:18 arsenic, found in old star, 9:15
    [Show full text]
  • Multi-D SNR Simulations with Particle Acceleration
    PACIFIC conference Gump Station, Moorea Sept 14, 2015 Multi-D SNR Simulations with Particle Acceleration Gilles Ferrand, University of Manitoba ([email protected]) in collaboration with Samar Safi-Harb (U of M) and Anne Decourchelle (CEA Saclay) Outline of the Talk Introduction: particle acceleration in supernova remnants - SNRs as Cosmic Ray accelerators - SNR structure and evolution 3D numerical simulations - hydro+kinetic code (Ramses+Blasi) - thermal emission - non-thermal emission - perspetives 1.1 The 3 dimensions of Cosmic Radiation mass spectrum energy spectrum angular spectrum isotropic radiation (random walk in B) [Iyono et al 2005] 99% of nucleons + 1% e- power-law, with breaks quasi-solar abundance, > 10 orders of magnitude with particularities in energy ! even at the highest energies? [Israel 2004] [Nagano & Watson 2000] [Pierre Auger Coll. 2010, 2012] 1.2 Particle acceleration in the Universe Engines of acceleration : massive stars, compact objects Physics of shocks, of accretion/ejection, of magnetic fields Active Gamma-Ray Galactic Bursts Nuclei interacting galaxies cosmic flows structures formation binary systems micro-quasars superbubbles supernovae and remnants Sun pulsars Galactic center OB associations stellar winds 1.3 The structure of a young supernova remnant Tycho’s SNR Warren et al 2005 seen by Chandra 0.95 – 1.26 keV (at age 433 yr) 1.63 – 2.26 keV 4.10 – 6.10 keV 1.4 The evolution of a supernova remnant radius R non-radiative radiative momentum-driven values given for pressure-driven 1.4 solar masses
    [Show full text]
  • Endpoints of Stellar Evolution
    Ay 1 – Lecture 10 Endpoints of Stellar Evolution Simeis 147 SNR 10.1 White Dwarfs and Contact Binaries Low Mass Stars End Up as White Dwarfs Red giant sheds its envelope, which becomes a planetary nebula Hot, inert core becomes a white dwarf White dwarf cools and becomes a black dwarf Degenerate Gas In a normal gas, decreasing volume increases pressure and/or temperature In a highly compressed gas, electrons and ions are packed close together Pauli’s exclusion principle states that in a given system, no two electrons can have the same energy state Once all available energy states are filled, the gas cannot be compressed further – this creates a degeneracy pressure, a consequence of quantum mechanics White Dwarfs • Gravity is balanced by the electron degeneracy pressure • The sizes are ~ the size of the planet Earth – Densities ~ 106 g/cm3 • The masses are up to ~ 1.4 M = the Chandrasekhar limit • Beyond that mass, pressure cannot balance the gravity, and the star collapses into a neutron star or a black hole • Increasing the mass decreases the radius: R ~ M–1/3 • Typical composition: C and/or O • Neutron stars are the equivalent of white dwarfs, but the degeneracy pressure is provided by neutrons, not electrons • The star cools passively as it radiates its latent heat,becoming fainter and cooler, and at some point it crystalises • Cooling time ~ many billions of years Stars in Close (Contact) Binaries They can interact (exchange mass), and that can significantly affect their evolution Roche lobe: the surface where the gravitational potential of the two stars is equal Inner Lagrange Point: the point between them where the two lobes connect Mass transfer in a close binary system occurs when at least one star overflows its Roche lobe Accretion to a Compact Companion If the accreting companion is a compact object (WD, NS, BH), the infalling material will form an accretion disk, which soaks up the excess angular momentum Accretion Power The material acquires a kinetic energy as it reaches the bottom of the potential well.
    [Show full text]