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The Physics of Supernovae Inma Domínguez Universidad de Granada Santiago de Chile, octubre de 2007 SN 1987A Chemical Evolution Cosmology Trigger Star formation Neutrinos BH, NS, GRBs Reionization of the Universe etc etc Supernovae are one of the most energetic explosive events in Nature • BRIGHT A SN in 10 sec releases 100 times the energy that the sun releases in all its life SN1054 was as luminous as the moon for some days • RARE: About 1 per century in our Galaxy Last recorded seen by naked-eye :1006 (Lupus), 1054 (Chinese), 1572 (Brahe), 1604(Kepler) • BRIEF: Luminosity falls by a factor of 100 in 4 months Standard Candles Fainter Further Distance Modulus Luminosity Distance SNe Classification Based on spectra and light curve morphology II P Type II II L SNe I b (strong He) I c (weak He) Core collapse of massive stars Type I I a (strong Si) Thermonuclear explosion Basic SN type spectra Light Curves Type Ia SN •Similar luminosity •Similar spectral evolution Good distance indicators Cosmological parameters Type II SN •Dramatic differences •II-P (plateau) •II-L (rapid declination) • Cosmology SNe RATE SN rate per unit Mass (10-10 M 10-2 yr (Ho/75)2 Galaxy Ia Ib/c II E-S0 0.04 < 0.01 < 0.01 S0a-Sb 0.065 0.026 0.12 S0c-Sd 0.17 0.067 0.74 Irr 0.77 0.21 1.7 Mannucci et al. 2005 SN Ib/c & SNII Absent in E-S0 Young populations Short lived progenitors Massive SN Ia in E-S0 Old populations Long lived progenitors Low mass in Binary Systems SN Ia rate in Spirals Galaxies-with SFR Part of SN Ia comes from a younger population Cappellaro et al 2003, Mannucci et al. 2005, Sullivan et al. 2006 Stellar Evolution M<0.8 M t>1/Ho 30 Myr<t< 15 Gyr 0.8<M/M<8 0.5<Mf /M<1.1 AGB SN Ia CO WD t~10-30 Myr 8<M/M<11 Mf =1.2-1.3 M ONeMg WD t~ 1-10 Myr 11<M/M<100 Mf =1.2-2.5 M SN II Ib/c Fe collapse NS/BH M>100 M t~ 1 Myr may or may not explode Classification of SNe ~ 4000 SNe (nowadays > 300 /yr) Solar System Abundances 1 0 H4 He -1 16O 12C O 20Ne Log Mass Fraction -2 -3 56Fe -4 -5 N=50 -6 N=126 N=82 -7 -8 -9 -10 -11 -12 0 20 40 60 80 100 120 Atomic Weight The most abundant isotopes: 1H 4He 16O 12C 20Ne (-elements) 140 160 180 200 220 50 yrs !! Origin of the Elements: Inside the Stars Observational Evidences: Pop II Less heavy elements by a factor of 100 Our Galaxy has synthesized 99 % of the heavy elements during ¡ts evolution Merril (1952) discovered Tc in All Tc isotopes decay t1/2 106 yr Tc has been synthesized inside the star Origin of the Elements: Nuclear Statistical Equilibrium (NSE) ? Klein, Beskow & Treffenberg (1947) Studied the abundances at NSE in function of T and rate nuc. re. = inverse rate N ( A, Z ) f (nn , T ) This mechanism could not reproduce the observed abundances But NOT bad for the Fe peak !! Binding Energy per nucleon BE/c2=[Zmp + (A-Z)mn - m(A,Z)] BE/A 56Fe © Rolfs & Rodney 1988 smallest mass per nucleon to 56Fe exothermic reactions The interpretation of the abundances The Peaks in the abundances of 4He, 12C, 16O, 20Ne and other elements capture nuclear reactions inside the stars Fe-peak elements 56Fe is the isotope with higher binding energy 56Fe is the last product of exothermic nuclear fusion reactions, NSE Elements heavier than Fe High Coulomb barrier for charge reactions Neutron captures Most abundant nuclei Nuclear Physics Physical Conditions Where & When ?? Anders & Grevesse 1989 Solar System Abundances © Cameron 1982 Abundances peak at the “magic numbers”,Z: 2, 8, 20, 28, 56, 82 He, O, Ca, Fe, Ba, Pb The familiar picture H burning (the most effective, with an average of 7MeV per nucleon of generated energy): produced 4He, 3He, and gives (generally secondary) contributions to intermediate nuclei up to Si. He burning (the second-most effective): produces 12C, some 20Ne, plus secondary chains starting from 14N or leading to neutron generation. 16O, 13C and Fusion of intermediate nuclei - 12C, 16O, 20Ne, 28Si nuclei below and up to the Fe-peak. Nuclear statistical equilibrium (NSE) processes, crossing the peak at 56Fe - 56Ni. Explosive nucleosynthesis, starting from NSE and reorganizing abundances up to 65Cu, occur in CCSNe and in SN Ia. Neutron captures (slow and rapid – s and r - processes). Solar System Abundances BBN AGB SNII SNII SNII ? SNIa BBN Anders & Grevesse 1989 Cameron 1982 AGB Some definitions… • “Metals”: elements heavier than helium, Z • “Metallicity”: [Fe/H] = log (Fe/H) – log (Fe/H) • “Abundance ratio”: [X/Y]= log (X/Y) – log (X/Y) * Abundance scale by number: * Mass fractions: X= Hydrogen (X~0.71) Y= Helium 4 (Y~0.27) Z= Metals (Z~0.02) Population I 12 log N(H) X+Y+Z= 1 objects (stars): Z ~ Z Population II : Z << Z Population III : Z ~ 0 (not detected yet ?) Stellar Evolution & Nucleosynthesis The activation of a nuclear burning phase The stellar life-time DEPEND on AGB Mass Planetary Nebulae White Dwarfs (if) Binary Systems Novae SNe Ia AIC: Neutron (Pulsars) M Tc R CCSNe Neutron (Pulsars) Black Holes “Less” in Z… Low mass stars M < 8 M AGB/Planetary Nebulae return C, N, s-elements etc to the ISM Exploding CO WDs (accreting mass from a companion) Type Ia Supernovae (SN Ia or Thermonuclear SNe) SN Ia produce ~2/3 of the observed Fe in the Universe Massive 25 M Chieffi, Limongi, Straniero 1998 Massive stars M ≥ 8-10 M Core Collapse Supernovae eject O, Mg, Ti and likely r-p-elements into the ISM Log Mass Fraction Origin of the elements 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 -11 -12 BB Novae SNIa 0 20 40 60 80 100 120 CR IMS s-r 140 neut. SNII 160 180 200 Atomic Weight BB = Big Bang; CR = Cosmic Rays; neut. = ν induced reactions in SNII; IMS = Intermediate Mass Stars; SNII = Core collapse supernovae; SNIa = Thermonuclear supernovae; s-r = slow-rapid neutron captures The Origin of the Elements up to Zn ApJS 1995 L* M < 8M neut. Irra CR Cosmic Rays s shell x Explosive rich freeze out Yields Low and Intermediate Mass Stars 4He C N s-process (A > 90) elements Lattanzio et al., Meynet & Maeder, Marigo et al., Siess et al. Straniero et al. (TERAMO), Siess et al., Van den Hoeck & Groenewegen Ventura et al. Type Ia Supernovae Fe and Fe-peak Nomoto et al., Iwamoto et al. Höflich et al., Thielemann et al. Massive stars -elements (O, Ne, Mg, Si, S, Ca), some Fe-peak, s-process elements (A < 90) and r-process elements. Woosley & Weaver / Limongi & Chieffi (ORFEO) Some definitions Yields Yield i Mass Loss !! t 0 ( X X i i )dm Meje in M Production Factor X dm i PFi Meje 0 X i dm Meje Yields + Evolution-Time Chemical Evolution SN II -elements SN Ia + SNII Fe 20Ne 24Mg 28Si 32S 36Ar time Mg / Fe log Mg / Fe - log Mg / Fe Chemical Evolution 40Ca -enhancements appear naturally due to the different life-times between SNII and SNIa… but at what level? and when? Modification of the IMF: more massive stars produce more “alphas” Modification of the SFR: more “alphas” produced before SNIa appear © McWilliam (1997) Ingredients of GCE Initial conditions Big Bang abundances Prompt initial enrichment Initial mass function (IMF) Relative birthrates of stars with different masses Star formation rate (SFR) Constant, burst, interruptions etc Stellar yields vs. stellar mass and metallicity SNII, SNIa, AGB, Novae, etc Galactic gas inflow/outflow Late infall of primordial gas etc Supernova-driven galactic winds etc Stellar & gas dynamics STELLAR EVOLUTION EQUATIONS P Gm m 4 r 4 1 Dimension Lagrangian Hydrostatic r 1 m 4 r 2 ( P, T , Yi ) L nuc ( P, T , Yi ) ( P, T , Yi ) grav ( P, T , Yi ) m T GmT dlnT ( P, T , Yi ) 2 dln P m 4 r P Yi ci ( j ) jY j ci ( j, k ) N A < v > j ,k Y jYk t j j ,k 2 c ( j , k , l ) N A < v > j , k ,l Y jYkYl i 2 j , k ,l i 1,........,N + Chemical Evolution STELLAR EVOLUTION EQUATIONS Convection (a problem !!) t mix t Time-dependent convection t mix t nuc Mixing-Nuclear burning coupled Micro-physics EOS Opacity Nuclear Cross Sections (Strong & Weak) Screening factors Neutrinos NUCLEAR NETWORK 60Zn 61Zn 62Zn 63Zn 64Zn 65Zn 66Zn 67Zn 68Zn High number of Isotopes High Number of Nuclear Reactions 57Cu 58Cu 59Cu 60Cu 61Cu 62Cu 63Cu 64Cu 65Cu 66Cu 67Cu 56Ni 57Ni 58Ni 59Ni 60Ni 61Ni 62Ni 63Ni 64Ni 65Ni 54Co 55Co 56Co 57Co 58Co 59Co 60Co 61Co 62Co 52Fe 53Fe 54Fe 55Fe 56Fe 57Fe 58Fe 59Fe 60Fe 61Fe 51Mn 52Mn 53Mn 54Mn 55Mn 56Mn 57Mn p, n and captures e± captures b± Decay 48Cr 49Cr 50Cr 51Cr 52Cr 53Cr 54Cr 55Cr 41Sc 42Sc 45V 46V 47V 48V 49V 50V 51V 52V 44Ti 45Ti 46Ti 47Ti 48Ti 49Ti 50Ti 51Ti 43Sc 44Sc 45Sc 46Sc 47Sc 48Sc 49Sc 50Sc 40Ca 41Ca 42Ca 43Ca 44Ca 45Ca 46Ca 47Ca 48Ca 49Ca 37K 38K 39K 40K 41K 42K 35Ar 36Ar 37Ar 38Ar 39Ar 40Ar 41Ar 1H 3He 4He 2H 3H 25Al 33Cl 34Cl 35Cl 36Cl 37Cl 38Cl 31S 32S 33S 34S 35S 36S 37S 29P 30P 31P 32P 33P 34P 27Si 28Si 29Si 30Si 31Si 32Si 33Si 26Al 27Al 28Al (,n) (p,n) b-, 23Mg 24Mg 25Mg 26Mg 27Mg n 21Na 22Na 23Na 24Na (p,g) (,p) 20Ne 21Ne 22Ne 23Ne 7Be 8Be 6Li 7Li 17F 18F 19F 20F 15O 16O 17O 18O 19O 13N 14N 15N 16N 12C 13C 14C 10B 11B 9Be 10Be (g,p) (p,) Extensive Nuclear Networks Automatic Adaptive Network (n,g) (g,n) (g,) (n,) (,g) b,(n,p) Strong reactions Weak reactions Neutrinos Initial stellar parameter (mass, chemical composition) Opacities Equation of State First model at the beginning of the Pre-MS Adaptive re-zoning Atmosphere Definition of Convective borders MAIN PROGRAM (Finite difference Henyey Method) Mixing Mass loss Physical evolution THE FRANEC CODE Chemical evolution Output New temporal step AGB Thermonuclear SNe Core Collapse SNe Evolution of Low & Intermediate Mass Stars Schematic structure of Schematic an AGBstructure star of an AGB star (not to scale) (not to scale) H-rich convective envelope H-burning shell He-burning shell He intershell C-O core Dredge-up Flash-driven intershell convection Evolutionary track toward the WD M=1 M PN 0.6 CO 0.5 He t =10 Gyr Remnant: CO WD 0.6 M 0.6 CO AGB 0.55 He 0.2 CO HB RGB 0.1 He WD MS Prada Moroni & Straniero 2002 A WD in a binary system toward a thermonuclear explosion WD + 2 WDs “Universally” accepted model for Ia: Thermonuclear Explosion of a CO WD M~MChandrasekhar ~ 1.4 M Light Curve 56Ni 56Co 56 Fe L time Supernova Cosmology Project Lmax MNi WD is degenerate e- Degenerate Pressure (EOS) 1926 Fowler Pauli Exclusion Principle Pressure for relativistic electrons: 3 1 2 3 PR 4 Z c A mH 4 3 The Chandrasekhar limit 2 M Ch 2 1.456 M e P independent of T Thermonuclear Explosion tnuc < thyd Thermonuclear Explosions WD WD RG SD WD DD MCh Propagation of the burning front Detonation vburnvsound Deflagration vburn< vsound Delayed detonation Deflagration Detonation Compressional heating ignition WD C or He detonation C-deflagration C-delayed detonation Still Key Problems to control SNIa !! Progenitors ? CO WD + companion SD vs DD… both ?? Accretion ?? CSM: 2002ic Hamuy et al. Nature 2003 2005gj Aldering et al. 2005 2006X Patat et al. Science 2007 NORMAL SNIa Explosion Mechanism ? begin subsonic 1D parametrization 3D still … fighting !! (Barcelona, Chicago, MPI, NRL) Massive Core Collapse At the end... Layered Structure Dense Iron Core 107 g·cm-3 T 1010 K MCore 1.4M RSi-Core 4000 km RFe-Core 800 km Massive Core Collapse Fusing H He C Ne O Si Main Fusion Products He C, O Ne, O O S, Si, Ar Fe, Cr Time 6 million years 700000 years 1000 years 9 Months 4 Months 1 day End result ? A star whose core looks like an onion Si Burning 54Fe, 56Fe, 55Fe, 58Ni, 53Mn O Conv. Shell 28Si, 32S, 36Ar, 40Ca, 34S, 38Ar C Conv. Shell 16O 28Si “Fe” 24Mg,25Mg, 27Al + s-process He Centrale 16O, 12C He Shell 16O, 12C H Centrale+Shell 14N, 13C, 17O H Centrale 4He 20Ne 20Ne, 23Na, H Shell He Shell He Centrale Main Products C conv. Shell Burning Site O conv. Shell Chieffi & Limongi Si burning(Cent.+Sehll) M=25M 12C + sprocess Collapse and Explosion 1H Core-Collapse Mechanism Once the star has finished its fuel the core cools because of two reasons: a) Iron dissociation fusion of light nuclei the star continues emitting energy b) Degenerate e- gas p + e-(2.25 MeV) n + e (neutronization) e escape and remove energy c) Contraction turns into a free-fall collapse, vast amount of neutrinos are produced In less than 1 second the inner core radius goes from 4000 km to 10 km (matter from the rest of the core is falling inward) Core-Collapse Mechanism Making Stars Explode Because the neutrinos free path is small the falling matter becames very hot and expands outwards. Finally, the star explodes and ejects the star’s outer layers into space. All that remains of is a very dense object: neutron star or black hole PROBLEM: Turning the implosion into an explosion !!! There are several models explaining the explosion, but until now simulations do not succeed in obtaining an explosion Core Collapse SNe: LCs Explosion Mechanism Still Uncertain simulated by a piston of initial velocity v0, located near the edge of the Fe core II-P 1. Rise: thermal energy (envelope is fully ionized) 2. Plateau: recombination of H Lenght MH 3. Radioactive Tail: 56Co decay L M56Ni 56Ni 56Co 56 Fe II-L No Plateau Small H-envelope Numerical Methods STELLAR EVOLUTION FRANEC (Chieffi, Domínguez, Imbriani, Limongi, Piersanti, Straniero) 1D Hydrostatic Code Extended Nuclear Network (700 isotopes) Physics and Chemestry coupled Time dependent mixing Low-mass PMS AGB WD TPs Massive PMS Fe-core Accretion Explosive C-ignition Numerical Methods EXPLOSION & LIGHT CURVES 1D Radiation-Hydrodynamic Code (PPM) (Höflich, Khokhlov ) Extended Nuclear Network (postprocess) Radiation transport via moments eq. Expansion opacities (scatt., bf, bb) Explosion mechanism: detonation SNIa deflagration piston CCSNe g Ray transport Monte Carlo LCs Frequency dependent transport eq. (1000 ) + Eddington fac. Mean opacities Observations LCs Spectra (evolution) Observed Relations 2001el SNIa Krisciunas et al. 2003 1999em IIP Hamuy et al. 2001 Lmax LC Lmax B-V Lmax VCa Lmax VNi 1999ee SNIa Hamuy et al. 2002 Information from the spectra Hoflich et al. 2000 + 15 days Star of Si burning -4 days C-burning MgII SN1999by 1.05m SNIa Sub-L CaII 1.15m Duration of these phases lower limit to the mass SN Remnants Crab Nebula SN 1054 Visible X-ray IR Radio Type Ia SN remnants: shocked ejecta O Fe Si S Ca Fe Ar XMM-Newton Tycho SN 1572 Interaction with the Ambient Medium AM~ 10-24 g/cm3 PDDT DDT X-ray emission spectra T Xi ionization Ca PDDT Fe Sub-Ch Identify Explosion Mechanism DDT Badenes et al. 2003 Cas A Chandra Si Fe Hwang et al. 2004 Age ~ 300 yr SN1680 Good spatial resolution X and Optical data CCSNe He-rich envelope SiXIII/MgXI Asymmetrically expanding Explosion ?? Vink et al. 2004 Bibliography BÖHM-VITENSE 1993, Introduction to Stellar Astrophysiscs, University of Chicago Press. CLAYTON 1992, Principles of Stellar Evolution and Nucleosynthesis, University of Chicago Press. HANSEN & KAWALER 1994, Stellar Interiors: Physical Principles, Structure and Evolution, Springer-Verlag KIPPENHAHN 1990, Principles of Stellar Structure and Evolution, Springer-Verlag. OSTLIE & CARROLL 1996, An Introduction to Modern Stellar Astrophysics, Addison Wesley. Bibliography PAGEL 1997, Nucleosynthesis and Chemical Evolution of Galaxies, Cambridge University Press. BUSSO, GALLINO, WASSERBURG 1999, Nucleosynthesis in AGB stars, Ann. Rev. A. &A., 36, 369. WALLERSTEIN et al. 1998, Synthesis of the elements in stars forty years of progress, Reviews of Modern Physics, Volume 69,