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The Nuclear Physics of Neutron Stars Exotic Beam Summer School 2015 Florida State University Tallahassee, FL - August 2015 J. Piekarewicz (FSU) Neutron Stars EBSS 2015 1 / 21 My FSU Collaborators My Outside Collaborators Genaro Toledo-Sanchez B. Agrawal (Saha Inst.) Karim Hasnaoui M. Centelles (U. Barcelona) Bonnie Todd-Rutel G. Colò (U. Milano) Brad Futch C.J. Horowitz (Indiana U.) Jutri Taruna W. Nazarewicz (MSU) Farrukh Fattoyev N. Paar (U. Zagreb) Wei-Chia Chen M.A. Pérez-Garcia (U. Raditya Utama Salamanca) P.G.- Reinhard (U. Erlangen-Nürnberg) X. Roca-Maza (U. Milano) D. Vretenar (U. Zagreb) J. Piekarewicz (FSU) Neutron Stars EBSS 2015 2 / 21 S. Chandrasekhar and X-Ray Chandra White dwarfs resist gravitational collapse through electron degeneracy pressure rather than thermal pressure (Dirac and R.H. Fowler 1926) During his travel to graduate school at Cambridge under Fowler, Chandra works out the physics of the relativistic degenerate electron gas in white dwarf stars (at the age of 19!) For masses in excess of M =1:4 M electrons becomes relativistic and the degeneracy pressure is insufficient to balance the star’s gravitational attraction (P n5=3 n4=3) ∼ ! “For a star of small mass the white-dwarf stage is an initial step towards complete extinction. A star of large mass cannot pass into the white-dwarf stage and one is left speculating on other possibilities” (S. Chandrasekhar 1931) Arthur Eddington (1919 bending of light) publicly ridiculed Chandra’s on his discovery Awarded the Nobel Prize in Physics (in 1983 with W.A. Fowler) In 1999, NASA lunches “Chandra” the premier USA X-ray observatory J. Piekarewicz (FSU) Neutron Stars EBSS 2015 3 / 21 Some Historical Facts Chandrasekhar shows that massive stars will collapse (1931) Chadwick discovers the neutron (1932) ... predicted earlier by Ettore Majorana but never published! Baade and Zwicky introduce the concept of neutron stars (1933) Oppenheimer-Volkoff compute masses of neutron stars using GR (1939) Predict M? '0:7 M as maximum NS mass or minimum black hole mass Jocelyn Bell discovers pulsars (1967) Gold and Pacini propose basic lighthouse model (1968) Pulsars are rapidly rotating Neutron Stars! J. Piekarewicz (FSU) Neutron Stars EBSS 2015 4 / 21 Jocelyn Bell Worked with Anthony Hewish on constructing a radio telescope to study quasars In 1967 as a graduate student (at the age of 24!) detected a bit of “scruff” Jocelyn Bell discovers amazing regularity in the radio signals( P =1:33730119 s) Speculated that the signal might be from another civilization (LGM-1) Paper announcing the first pulsar published in Nature (February 1968) A Hewish, S J Bell, J D H Pilkington, P F Scott, R A Collins Antony Hewish and Martin Ryle awarded the Nobel Prize in Physics in 1974 The “No-Bell” roundly condemned by many astronomers (Fred Hoyle) “I believe it would demean Nobel Prizes if they were awarded to research students, except in very exceptional cases, and I do not believe this is one of them” J. Piekarewicz (FSU) Neutron Stars EBSS 2015 5 / 21 Table of Contents 5 Neutron Star Crust: Preface by Jocelyn Bell Table of Contents Preface ...................................................................... 1 Introduction ................................................................. 3 Neutron star crust and molecular dynamics simulation C. J. Horowitz, J. Hughto, A. Schneider, and D. K. Berry . 6 Nuclear pasta in supernovae and neutron stars Preface 1 G. Watanabe and2JocelynBellBurnell T. Maruyama . 26 Terrestrial andthe field, astrophysical both observational andsuperfluidity: theoretical, and identify coldsome atoms of the critical and problems neutron on matter A. Gezerlis andwhich J. majorCarlson progress may . .be . expected. .in . the . next . .. decade. 48 Dr. Carlos Bertulani’s and Dr. Jorge Piekarewicz’s goal has been to put together a Pairing correlationscomprehensive and review thermodynamic of some of the main theoretical properties ideas related of toinner the structure crust and matter dynamics of neutron stars, with special emphasis on the nuclear physics. I have found J. Margueron andthe idea N. very Sandulescu timely and have gladly . accepted . their . invitati . .on . to . write. .. the . preface . to. this . 68 Preface The crust ofcollection spinning-down of review articles. neutron stars Ibelievethatthisbookwillhaveawidereadership.Mostarticles are accessible to a R. Negreiros, S.graduate Schramm, student, or to and a non-practitioner F. Weber researcher, . wit . .hout . much. knowledge . of. the . field. 87 Moreover, I expect that this book will become a useful resource for the many established Influence ofpractitioners. the nuclear I hope you symmetry agree with me, find energy the book enjoyabon thele tostructure read, and useful to and have composition of the Jocelyn Bell Burnell ∗ University of Oxford, Denys Wilkinson Building outer crust on your shelves. Keble Road, Oxford OX1 3RH, UK X. Roca-Maza, J. Piekarewicz, T. Garc´ıa-Galvez,´ and M. Centelles . 104 Jocelyn Bell Burnell Equation of stateUniversity for of Oxford proto-neutron star Ijudgemyselffortunatetobeworkinginanexcitingandfastmoving area January 2012 of science and at a time when the public has become fascinated by questions re- G.Shen .................................................................... 129 garding the birth and evolution of stars, the nature of dark matter and dark en- From nuclei to nuclear pasta ergy, the formation of black holes and the origin and evolution of the universe. C.O. Dorso, P.A. G´ımenez-Molinelli, and J.A. Lopez´ . 151 The physics of neutron stars is one of these fas- The structure of the neutron star crust within a semi-microscopic energy density func- cinating subjects. Neutron stars are formed in su- pernova explosions of massive stars or by accretion- tional method induced collapse of smaller white dwarf stars. Their existence was confirmed through the discovery of ra- M. Baldo and E.E. Saperstein . 171 dio pulsars during my thesis work in 1967. Since The inner crust and its structure then this field has evolved enormously. Today we know of accretion-powered pulsars which are pre- D.P. Menezes, S.S. Avancini, C. Providencia,ˆ and M.D. Alloy . 194 dominantly bright X-ray sources, rotation-powered pulsars observed throughout the electromagnetic Neutron-star crusts and finite nuclei spectrum, radio-quiet neutron stars, and highly mag- S. Goriely, J. M. Pearson, and N. Chamel . 214 netized neutron stars or magnetars. No wonder there has been an explosion in the research activity related The nuclear symmetry energy, the inner crust, and global neutron star modeling to neutron stars! W.G. Newton, M. Gearheart, J. Hooker, and Bao-An Li . 236 It is now hard to collect in a single book what we already know about neutron stars along with some of Neutron starquakes and the dynamic crust the exciting new developments. In this volume ex- perts have been asked to articulate what they believe A.L.Watts . 266 are the critical, open questions in the field. In order for the book to be useful to a more Thermal and transport properties of the neutron star inner crust general audience, the presentations also aim to be as pedagogical as possible. This book is a collection of articles on the neutron stars themselves, written by well- D. Page and S. Reddy . 282 known physicists. It is written with young researchers as thetargetaudience,tohelpthis new generation move the field forward. The invited authors summarize the current status of Quantum description of the low-density inner crust: finite size effects and linear re- ∗[email protected] sponse, superfluidity, vortices P. Avogadro, F. Barranco, R.A. Broglia, and E. Vigezzi . 309 J. Piekarewicz (FSU) Neutron Stars EBSS 2015 6 / 21 Biography of a Neutron Star: The Crab Pulsar SN 1054 first observed as a new “star” in the sky on July 4, 1054 Event recorded in multiple Chinese and Japanese documents Event also recorded by Anasazi residents of Chaco Canyon, NM Crab nebula and pulsar became the SN remnants Name: PSR B0531+21 Distance: 6,500 ly POB: Taurus Temperature: 106 K Mass: 1.4 M Density: 1014g/cm3 Radius: 10 km Pressure: 1029 atm Period: 33 ms Magnetic Field: 1012 G J. Piekarewicz (FSU) Neutron Stars EBSS 2015 7 / 21 A Grand Challenge: How does subatomic matter organize itself? “Nuclear Physics: Exploring the Heart of Matter” (2010 Committee on the Assessment and Outlook for Nuclear Physics) Consider A nucleons and Z leptons in a fixed volume V at T ≡0 ... cold fully catalyzed matter in thermal and chemical equilibrium Enforce charge neutrality protons = electrons + muons Enforce chemical (i.e., beta) equilibrium: n!p+e− +¯ν; p+e− !n+ν Impossible to answer such a question under normal laboratory conditions — as such a system is in general unbound! J. Piekarewicz (FSU) Neutron Stars EBSS 2015 8 / 21 Neutron Stars as Nuclear Physics Gold Mines Neutron Stars are the remnants of massive stellar explosions Are bound by gravity NOT by the strong force Satisfy the Tolman-Oppenheimer-Volkoff equation( vesc=c ∼1=2) Only Physics sensitive to: Equation of state of neutron-rich matter EOS must span about 11 orders of magnitude in baryon density Increase from 0.7!2M must be explained byLETTER NuclearRESEARCH Physics! Received 7 July;dM accepted 1 September 2010. MS0 2 2.5 GR MPA1 = 4 r E(r) ∞ AP3 1. Lattimer, J. M. & Prakash, M. Theπ physics of neutron stars. Science 304, 536–542 < PAL1 P ENG (2004). dr AP4 MS2 2. Lattimer, J. M. & Prakash, M. Neutron star observations: prognosis for equation of Causality state constraints.dP Phys. Rep. 442, 109–165E(r (2007).)M(r) P(r) 2.0 J1614-2230 3. Glendenning, N. K. &= Schaffner-Bielich,−G J. Kaon condensation and1 dynamical+ SQM3 MS1 nucleons in neutron stars. Phys. Rev. Lett. 81, 4564–45672 (1998). J1903+0327 FSU 4. Lackey, B. D.,dr Nayyar, M. & Owen, B. J. Observationalr constraints on hyperonsE in (r) ) ( SQM1 PAL6 GM3 neutron stars.
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