Magnetic Neutron Star Cooling and Microphysics A
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Chiral Symmetry Restoration by Parity Doubling and the Structure of Neutron Stars
Chiral symmetry restoration by parity doubling and the structure of neutron stars Micha l Marczenko,1 David Blaschke,1, 2, 3 Krzysztof Redlich,1, 4 and Chihiro Sasaki1 1Institute of Theoretical Physics, University of Wroc law, PL-50204 Wroc law, Poland 2Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia 3National Research Nuclear University, 115409 Moscow, Russia 4Extreme Matter Institute EMMI, GSI, D-64291 Darmstadt, Germany (Dated: November 14, 2018) We investigate the equation of state for the recently developed hybrid quark-meson-nucleon model under neutron star conditions of β−equilibrium and charge neutrality. The model has the character- istic feature that, at increasing baryon density, the chiral symmetry is restored within the hadronic phase by lifting the mass splitting between chiral partner states, before quark deconfinement takes place. Most important for this study are the nucleon (neutron, proton) and N(1535) states. We present different sets for two free parameters, which result in compact star mass-radius relations in accordance with modern constraints on the mass from PSR J0348+0432 and on the compactness from GW170817. We also consider the threshold for the direct URCA process for which a new relationship is given, and suggest as an additional constraint on the parameter choice of the model that this process shall become operative at best for stars with masses above the range for binary radio pulsars, M > 1:4 M . I. INTRODUCTION neutron stars. However, already before this occurs, a strong phase transition manifests itself by the appearance The investigation of the equation of state (EoS) of com- of an almost horizontal branch on which the hybrid star pact star matter became rather topical within the past solutions lie, as opposed to the merely vertical branch of few years, mainly due to the one-to-one correspondence pure neutron stars. -
Convective Urca Process and Cooling in Dense Stellar Matter
Convective Urca Process and cooling in dense stellar matter M. Schoenberg: The name Urca was given by us to the process which accompanies the emission of neutrino in supernova because of the following curious situation: In Rio de Janeiro, we went to play at the Casino-da-Urca and Gamow was very impressed with the table in which there was a roulette, in which money disappeared very quickly. With a sense of humor, he said: ‘Well, the energy is being lost in the centre of supernova with almost the same rapidity as money does from these tables!’ (from Grib, Novello: “Gamow in rio and the discovery of the URCA process”, Astronom & Astrophys. Trans. 2000, Vol 19) Feb 10 2010, Advisor-Seminar WS09/10 by Fabian Miczek Urca reactions Urca pairs consist of mother (M) and daughter (D) nuclei Urca reactions A A − - beta decay: Z1M Z De e A − A - electron capture: Z De Z 1Me Central questions: Is a continuous cycling between mother and daugter possible? Both reactions emit a neutrino => possible cooling mechanism? 2 electron captures require a threshold energy Eth=EM−ED−me c beta decays release the threshold energy M We're interested in degenerate stellar matter (ideal gas of ions, Fermi gas of electrons) E th threshold energy can be provided by e- mc2 the Fermi energy of the electrons D Example (E = 4.4 MeV) 23 23 − th Na Nee e 23 − 23 Nee Nae Electron captures in degenerate matter Fermi energy > threshold energy assume zero temperature ( kT << E ) F A − A Z De Z 1 M e energy heat M neutrino Fermi electron threshold e- mc2 density of states D -
X-Ray Sun SDO 4500 Angstroms: Photosphere
ASTR 8030/3600 Stellar Astrophysics X-ray Sun SDO 4500 Angstroms: photosphere T~5000K SDO 1600 Angstroms: upper photosphere T~5x104K SDO 304 Angstroms: chromosphere T~105K SDO 171 Angstroms: quiet corona T~6x105K SDO 211 Angstroms: active corona T~2x106K SDO 94 Angstroms: flaring regions T~6x106K SDO: dark plasma (3/27/2012) SDO: solar flare (4/16/2012) SDO: coronal mass ejection (7/2/2012) Aims of the course • Introduce the equations needed to model the internal structure of stars. • Overview of how basic stellar properties are observationally measured. • Study the microphysics relevant for stars: the equation of state, the opacity, nuclear reactions. • Examine the properties of simple models for stars and consider how real models are computed. • Survey (mostly qualitatively) how stars evolve, and the endpoints of stellar evolution. Stars are relatively simple physical systems Sound speed in the sun Problem of Stellar Structure We want to determine the structure (density, temperature, energy output, pressure as a function of radius) of an isolated mass M of gas with a given composition (e.g., H, He, etc.) Known: r Unknown: Mass Density + Temperature Composition Energy Pressure Simplifying assumptions 1. No rotation à spherical symmetry ✔ For sun: rotation period at surface ~ 1 month orbital period at surface ~ few hours 2. No magnetic fields ✔ For sun: magnetic field ~ 5G, ~ 1KG in sunspots equipartition field ~ 100 MG Some neutron stars have a large fraction of their energy in B fields 3. Static ✔ For sun: convection, but no large scale variability Not valid for forming stars, pulsating stars and dying stars. 4. -
On the Theory of Gamma-Ray and Fast Radio Bursts
On the Theory of Gamma-ray and Fast Radio Bursts D. Skripachov Abstract Gamma-ray bursts are characterized by energy comparable to the rest mass of stars and duration comparable to the time of passage of light of several diameters of star. It means GRBs signal the flares occur when stars fall on supermassive neutron collapsars (SMNC) located at the centers of galaxies. Long, short, very short and weak GRBs are matched the fall of main sequence stars, white dwarfs, neutron stars (NS) and rogue planets, respectively. GRB is the result of heating of star caused by the action of three factors: transverse compression of angular convergence to SMNC, friction of light matter (LM), and volumetric compression of the entry into gravitationally distended space. GRB is a circular flare in the stellar corona. GRB lasts until the star will be hidden under the π- horizon, on which the angle of gravitational deflection of beams is 180°. Multiple peaks are caused by the fall of binary stars and stars with planets, as well as by consecutive bursts of stellar core and overlying layers. Early afterglow is due to the annihilation, and later (x-ray and radio) due to aurora and remanence of LM. FRB precedes very short GRB. Milliseconds before GRB, "magnetic lightning" arises, which is a reconnection of magnetic field lines from NS anterior pole to SMNC. Magnetic dipoles of LM nuclei are aligned along the magnetic lines of force. This is accompanied by radio emission generated strictly perpendicular magnetic tube connecting NS and SMNC. Gravitation bends the plane of FRB in the hyperboloid with the cone angle of 40°. -
Stars IV Stellar Evolution Attendance Quiz
Stars IV Stellar Evolution Attendance Quiz Are you here today? Here! (a) yes (b) no (c) my views are evolving on the subject Today’s Topics Stellar Evolution • An alien visits Earth for a day • A star’s mass controls its fate • Low-mass stellar evolution (M < 2 M) • Intermediate and high-mass stellar evolution (2 M < M < 8 M; M > 8 M) • Novae, Type I Supernovae, Type II Supernovae An Alien Visits for a Day • Suppose an alien visited the Earth for a day • What would it make of humans? • It might think that there were 4 separate species • A small creature that makes a lot of noise and leaks liquids • A somewhat larger, very energetic creature • A large, slow-witted creature • A smaller, wrinkled creature • Or, it might decide that there is one species and that these different creatures form an evolutionary sequence (baby, child, adult, old person) Stellar Evolution • Astronomers study stars in much the same way • Stars come in many varieties, and change over times much longer than a human lifetime (with some spectacular exceptions!) • How do we know they evolve? • We study stellar properties, and use our knowledge of physics to construct models and draw conclusions about stars that lead to an evolutionary sequence • As with stellar structure, the mass of a star determines its evolution and eventual fate A Star’s Mass Determines its Fate • How does mass control a star’s evolution and fate? • A main sequence star with higher mass has • Higher central pressure • Higher fusion rate • Higher luminosity • Shorter main sequence lifetime • Larger -
Stellar Structure and Evolution
Lecture Notes on Stellar Structure and Evolution Jørgen Christensen-Dalsgaard Institut for Fysik og Astronomi, Aarhus Universitet Sixth Edition Fourth Printing March 2008 ii Preface The present notes grew out of an introductory course in stellar evolution which I have given for several years to third-year undergraduate students in physics at the University of Aarhus. The goal of the course and the notes is to show how many aspects of stellar evolution can be understood relatively simply in terms of basic physics. Apart from the intrinsic interest of the topic, the value of such a course is that it provides an illustration (within the syllabus in Aarhus, almost the first illustration) of the application of physics to “the real world” outside the laboratory. I am grateful to the students who have followed the course over the years, and to my colleague J. Madsen who has taken part in giving it, for their comments and advice; indeed, their insistent urging that I replace by a more coherent set of notes the textbook, supplemented by extensive commentary and additional notes, which was originally used in the course, is directly responsible for the existence of these notes. Additional input was provided by the students who suffered through the first edition of the notes in the Autumn of 1990. I hope that this will be a continuing process; further comments, corrections and suggestions for improvements are most welcome. I thank N. Grevesse for providing the data in Figure 14.1, and P. E. Nissen for helpful suggestions for other figures, as well as for reading and commenting on an early version of the manuscript. -
Stellar Coronal Astronomy
Stellar coronal astronomy Fabio Favata ([email protected]) Astrophysics Division of ESA’s Research and Science Support Department – P.O. Box 299, 2200 AG Noordwijk, The Netherlands Giuseppina Micela ([email protected]) INAF – Osservatorio Astronomico G. S. Vaiana – Piazza Parlamento 1, 90134 Palermo, Italy Abstract. Coronal astronomy is by now a fairly mature discipline, with a quarter century having gone by since the detection of the first stellar X-ray coronal source (Capella), and having benefitted from a series of major orbiting observing facilities. Several observational charac- teristics of coronal X-ray and EUV emission have been solidly established through extensive observations, and are by now common, almost text-book, knowledge. At the same time the implications of coronal astronomy for broader astrophysical questions (e.g. Galactic structure, stellar formation, stellar structure, etc.) have become appreciated. The interpretation of stellar coronal properties is however still often open to debate, and will need qualitatively new ob- servational data to book further progress. In the present review we try to recapitulate our view on the status of the field at the beginning of a new era, in which the high sensitivity and the high spectral resolution provided by Chandra and XMM-Newton will address new questions which were not accessible before. Keywords: Stars; X-ray; EUV; Coronae Full paper available at ftp://astro.esa.int/pub/ffavata/Papers/ssr-preprint.pdf 1 Foreword 3 2 Historical overview 4 3 Relevance of coronal -
White Dwarfs - Degenerate Stellar Configurations
White Dwarfs - Degenerate Stellar Configurations Austen Groener Department of Physics - Drexel University, Philadelphia, Pennsylvania 19104, USA Quantum Mechanics II May 17, 2010 Abstract The end product of low-medium mass stars is the degenerate stellar configuration called a white dwarf. Here we discuss the transition into this state thermodynamically as well as developing some intuition regarding the role of quantum mechanics in this process. I Introduction and Stellar Classification present at such high temperatures are small com- pared with the kinetic (thermal) energy of the parti- It is widely believed that the end stage of the low or cles. This assumption implies a mixture of free non- intermediate mass star is an extremely dense, highly interacting particles. One may also note that the pres- underluminous object called a white dwarf. Obser- sure of a mixture of different species of particles will vationally, these white dwarfs are abundant (∼ 6%) be the sum of the pressures exerted by each (this is in the Milky Way due to a large birthrate of their pro- where photon pressure (PRad) will come into play). genitor stars coupled with a very slow rate of cooling. Following this logic we can express the total stellar Roughly 97% of all stars will meet this fate. Given pressure as: no additional mass, the white dwarf will evolve into a cold black dwarf. PT ot = PGas + PRad = PIon + Pe− + PRad (1) In this paper I hope to introduce a qualitative de- scription of the transition from a main-sequence star At Hydrostatic Equilibrium: Pressure Gradient = (classification which aligns hydrogen fusing stars Gravitational Pressure. -
Participant List Xiamen-CUSTIPEN Workshop, Xiamen, January 3 to 7, 2019
Participant list Xiamen-CUSTIPEN Workshop, Xiamen, January 3 to 7, 2019 No. Name Affiliation Email 01 Shunke Ai 艾舜轲 Beijing Normal University, China [email protected]. edu.cn 02 Nils Andersson University of Southampton, UK N.A.Andersson@sot on.ac.uk Contribution Title: Using gravitational waves to constrain matter at extreme densities Abstract: The spectacular GW170817 neutron star merger event provided interesting constraint on neutron star physics (in terms of the tidal deformability). Future detections are expected improve on this. In this talk I will discuss if we can expect to also make progress on issues relating to the composition and state of matter. 03 Zhan Bai 摆展 Peking University, China [email protected] n Contribution Title: Constraining Hadron-Quark Phase Transition Chemical Potential via Astronomical observation 04 Shishao Bao 鲍世绍 Shanxi Normal University, China [email protected] du.cn 05 Andreas Bauswein GSI Darmstadt, Germany Andreas.Bauswein @h-its.org Contribution Title: Neutron star mergers and the high-density equation of state 06 Subrata kumar Biswal Institute of Theoretical Physics, [email protected] Chinese Academy of Sciences, China Contribution Title: Effects of the φ-meson on the hyperon production in the hyperon star Abstract: Using relativistic mean field formalism, we have studied the effects of the strange vector φ-meson on the equation of state and consequently on the maximum mass and radius of the hyperon star. Effects of the hyperon coupling constants on the strangeness content of the hyperon star are discussed with a number of the relativistic parameter set. The canonical mass-radius relationship also discussed with various relativistic parameter set. -
A Teaching-Learning Module on Stellar Structure and Evolution
EPJ Web of Conferences 200, 01017 (2019) https://doi.org/10.1051/epjconf/201920001017 ISE2A 2017 A teaching-learning module on stellar structure and evolution Silvia Galano1, Arturo Colantonio2, Silvio Leccia3, Emanuella Puddu4, Irene Marzoli1 and Italo Testa5 1 Physics Division, School of Science and Technology, University of Camerino, Via Madonna delle Carceri 9, I-62032 Camerino (MC), Italy 2 Liceo Scientifico e delle Scienze Umane “Cantone”, Via Savona, I-80014 Pomigliano d'Arco, Italy 3 Liceo Statale “Cartesio”, Via Selva Piccola 147, I-80014 Giugliano, Italy 4 INAF - Capodimonte Astronomical Observatory of Naples, Salita Moiariello, 16, I-80131 Napoli, Italy 5 Department of Physics “E. Pancini”, “Federico II” University of Napoli, Complesso Monte S.Angelo, Via Cintia, I-80126 Napoli, Italy Abstract. We present a teaching module focused on stellar structure, functioning and evolution. Drawing from literature in astronomy education, we identified three key ideas which are fundamental in understanding stars’ functioning: spectral analysis, mechanical and thermal equilibrium, energy and nuclear reactions. The module is divided into four phases, in which the above key ideas and the physical mechanisms involved in stars’ functioning are gradually introduced. The activities combine previously learned laws in mechanics, thermodynamics, and electromagnetism, in order to get a complete picture of processes occurring in stars. The module was piloted with two intact classes of secondary school students (N = 59 students, 17–18 years old) and its efficacy in addressing students’ misconceptions and wrong ideas was tested using a ten-question multiple choice questionnaire. Results support the effectiveness of the proposed activities. Implications for the teaching of advanced physics topics using stars as a fruitful context are briefly discussed. -
The Single Degenerate Progenitor Scenario for Type Ia Supernovae and the Convective Urca Process
The Single Degenerate Progenitor Scenario for Type Ia Supernovae and the Convective Urca Process ADissertationpresented by Donald Eugene Willcox to The Graduate School in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Physics Stony Brook University August 2018 Stony Brook University The Graduate School Donald Eugene Willcox We, the dissertation committe for the above candidate for the Doctor of Philosophy degree, hereby recommend acceptance of this dissertation Alan Calder – Dissertation Advisor Associate Professor, Physics and Astronomy Michael Zingale – Chairperson of Defense Associate Professor, Physics and Astronomy Joanna Kiryluk – Committee Member Associate Professor, Physics and Astronomy Matthew Reuter – External Committee Member Assistant Professor, Applied Mathematics and Statistics This dissertation is accepted by the Graduate School Charles Taber Dean of the Graduate School ii Abstract of the Dissertation The Single Degenerate Progenitor Scenario for Type Ia Supernovae and the Convective Urca Process by Donald Eugene Willcox Doctor of Philosophy in Physics Stony Brook University 2018 This dissertation explores the e↵ects of properties of the progenitor massive white dwarf (WD) on thermonuclear (Type Ia) supernovae. It includes a study of explosions from “hy- brid” C/O/Ne progenitors and focuses primarily on the convective Urca process occurring in C/O progenitors shortly before their explosion. Pre-supernova WDs approaching the Chan- drasekhar mass can possess sufficiently high central densities that 23Na synthesized via 12C fusion undergoes electron capture to 23Ne. Convection sweeps 23Ne to regions of lower den- sity where it reverts via beta decay to 23Na, and vice versa. Cyclic weak nuclear processes of this type constitute the convective Urca process in WDs. -
Stellar Evolution Microcosm of Astrophysics
Nature Vol. 278 26 April 1979 Spring books supplement 817 soon realised that they are neutron contrast of the type. In the first half stars. It now seems certain that neutron Stellar of the book there are only a small stars rather than white dwarfs are a number of detailed alterations but later normal end-product of a supernova there are much more substantial explosion. In addition it has been evolution changes, particularly dn chapters 6, 7 realised that sufficiently massive stellar and 8. The book is essentially un remnants will be neither white dwarfs R. J. Tayler changed in length, the addition of new nor neutron stars but will be black material being balanced by the removal holes. Rather surprisingly in view of Stellar Evolution. Second edition. By of speculative or unimportant material. the great current interest in close A. J. Meadows. Pp. 171. (Pergamon: Substantial changes in the new binary stars and mass exchange be Oxford, 1978.) Hardback £7.50; paper edition include the following. A section tween their components, the section back £2.50. has been added on the solar neutrino on this topic has been slightly reduced experiment, the results of which are at in length, although there is a brief THE subject of stellar structure and present the major question mark mention of the possible detection of a evolution is believed to be the branch against the standard view of stellar black hole in Cygnus X-1. of astrophysics which is best under structure. There is a completely revised The revised edition of this book stood.