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EVOLUTIONARY PATH TOWARD THE CORE COLLAPSE SUPERNOVA EXPLOSION

EVOLUTIONARY PATH TOWARD THE CORE COLLAPSE SUPERNOVA EXPLOSION. Marco Limongi INAF – Osservatorio Astronomico di Roma, ITALY Institute for the Physics and Mathematics of the Universe , JAPAN marco.limongi@ oa-roma.inaf.it. and Alessandro Chieffi

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EVOLUTIONARY PATH TOWARD THE CORE COLLAPSE SUPERNOVA EXPLOSION

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  1. EVOLUTIONARY PATH TOWARD THE CORE COLLAPSE SUPERNOVA EXPLOSION Marco Limongi INAF – Osservatorio Astronomico di Roma, ITALY Institutefor the Physics and Mathematics of the Universe, JAPAN marco.limongi@oa-roma.inaf.it and Alessandro Chieffi INAF – Istituto di Astrofisica Spaziale e Fisica Cosmica, Italy alessandro.chieffi@iasf-roma.inaf.it

  2. OVERVIEW OF MASSIVE STARS PRESUPERNOVA EVOLUTION Grid of models: 13, 15, 20, 25, 30, 40, 60, 80 and 120 M Initial Solar Composition(Asplund et al. 2009) Allmodelscomputed with the FRANEC (Frascati RAphson Newton Evolutionary Code) 6.0 Major improvements compared to the release 4.0 (Limongi & Chieffi2003) and 5.0 (Limongi & Chieffi 2006) • FULL COUPLING of: Physical Structure - Nuclear Burning - Chemical Mixing (convection, semiconvection, rotation) - INCLUSION OF ROTATION: - Conservative rotation law - Transport of Angular Momentum (Advection/Diffusion) - Coupling of Rotation and Mass Loss - TWO NUCLEAR NETWORKS: - 163 isotopes (448 reactions) H/He Burning - 282 isotopes (2928 reactions) Advanced Burning - MASS LOSS: - OB: Vinket al. 2000,2001 - RSG: de Jager 1988+Van Loon 2005 (Dust driven wind) - WR: Nugis & Lamers 2000/Langer 1989

  3. MASSIVE STARS: CORE H BURNING Convective Core g g g CNO Cycle g g Core H burning models g g g

  4. WNL

  5. WNL

  6. MASSIVE STARS: CORE He BURNING 3a+ 12C(a,g)16O He Convective Core Core He burning models g g g WR Core He burning models g g Core H burning models g g H burningshell H exhausted core (He Core) g The location of a core He burning star in the HR diagram depends on the mass of its H envelope. The Mass Loss rate during the RSG phase is crucial in determining if and when (at which stage of core He burning) such a transition occurs and if and when the star enters the Wolf-Rayet stage or becomes a YSG

  7. WNL WNL WNE WNE WNC WNC WC WC

  8. WNL WNL WNE WNE WNC WNC WC WC

  9. EVOLUTION DURING H AND He BURNING: SUMMARY Compatible with recent observational estimates (Smartt et al. 2009): Compatible with the observed rates (Cappellaro & Turatto 99) Live a substantial fraction of time as RSG and explode as as IIb/Ib solve the RSG problem (Smartt et al. 2009)

  10. COMPARISON WITH WOLF-RAYET STARS POPULATION Constant SF + Salpeter IMF - Too few WR-stars predicted compared to O-type stars - WNC/WR in good agreement with observations (semiconvection during core He burning) – MM03 claimed that such an agreement could be achieved only with the inclusion of rotation - Too many WN predicted compared to WCO - WR predicted masses higher than the observed ones

  11. MASSIVE STARS: NEUTRINO LOSSES Neutrino losses play a dominantrole in the evolution of a massive star beyond core He burning The NuclearLuminosity (Lnuc) closelyfollows the energylosses Each burning stage gives about the same Enuc Evolutionarytimes of the advancedburningstages reduce dramatically Surfaceproperties (Mass Loss, Teff, L) do notchangeanymoretill the explosion

  12. ADVANCED BURNING STAGES: INTERNAL EVOLUTION Four major burnings, i.e., carbon, neon, oxygen and silicon. He C C O Si O C He H Ne Si O C Central burning  formation of a convective core Central exhaustion  shell burning  convective shell Local exhaustion shellburningshiftsoutward in mass  convectiveshell

  13. ADVANCED BURNING STAGES: INTERNAL EVOLUTION The details of thisbehavior (number, timing, mass extension and overlapof convectiveshells) ismainlydriven by the CO core mass and by itschemicalcomposition (12C, 16O) CO core mass Thermodynamic history Basic fuel for all the nuclearburningstagesafter core He burning 12C, 16O At core He exhaustionboth the mass and the composition of the CO core scale with the initialmass…

  14. ADVANCED BURNING STAGES: INTERNAL EVOLUTION ...hence, the evolutionarybehaviorscalesaswell He He C O C C Si O C H He He H O Si Ne Si O C O Ne Si In general, one to four carbon convectiveshells and one to threeconvectiveshellepisodes for each of the neon, oxygen and siliconburningsoccur. The number of C convectiveshellsdecreasesas the mass of the CO core increases (not the total mass!) or asthe12C left over by core He burningdecreases.

  15. PRESUPERNOVA STAR …and also the densitystructure of the star at the presupernova stage The final Fe core Massesrangebetween: MFe=1.14-1.80 M In general the higheris the mass of the CO core (the loweris the 12C left over by the core He burning), the more compact is the structureat the presupernova stage

  16. PRESUPERNOVA STAR The complexinterplayamong the shellnuclearburnings and the timing of the convectivezonesdetermines in a direct way the finaldistribution of the chemicalcomposition. The mass losshistory (RSG/WR) determines in a direct way the kind of CCSN

  17. Shock Wave Compression and Heating Matter Falling Back Matter Ejected into the ISM Ekin1051 erg Induced Expansion and Explosion Mass Cut Initial Remnant Final Remnant Initial Remnant Fe core INDUCED EXPLOSION AND FALLBACK • Piston (Woosley & Weaver) • Thermal Bomb (Nomoto & Umeda) • KineticBomb (Chieffi & Limongi) Different ways of inducing the explosion FB depends on the binding energy: the higher is the initial mass the higher is the binding energy

  18. THE FINAL FATE OF A MASSIVE STAR Hydrodynamic models based on induced explosions No (or very few) bright SNIb/c predicted No neutron stars formed by massive progenitors (contrary to recent observational evidences, see Smartt et al. 2009) Thorsett & Chakrabarty (1999)

  19. SUMMARY • Maximum mass evolvingas a RSG on a substantialfraction of core He burning Mmax,RSG ~ 35 M - Consistent with the maximum luminosity of galactic RSG stars • The minimum masses for the formation of the various kind of Wolf-Rayet stars are: MWNL ~ 23 M MWNE ~ 35 M MWC ~ 45 M - WR/O significanlty underestimated compared to observations - WNC/WR in good agreement with observations - Too many WN predicted compared to WCO - WR predicted masses higher than the observed ones • RSG/YSG/BSG SNe as a function of the initial mass M≤ 22 M RSG-SN 22 M < M≤ 35 M YSG-SN 35 M < M BSG-SN

  20. SUMMARY • Maximum mass for SNII-P Mmax,IIP ~ 17 M - Consistent with the recent observational estimates (Smartt et al. 2009) MSNII/SNIbc ~ 35 M • Minimum mass for SNIb/c: In principle compatible with the observed rates • The final Fe core Masses range between: MFe=1.14-1.80 M • The limiting mass between NS and BH fromingSNe : MNS/BH ~ 22 M in agreement with • Because of the large fallback No (or very few) bright SNIb/c predicted - Large uncertainties in treatment of the fallback - Mixing and Fallback (Umeda & Nomoto) - Larger energies / Binary channel

  21. PHYSICS OF ROTATION STRUCTURE • Oblateness (interior, surface)‏ • New structure equations Meridional Circulation Von ZeipelTheorem G. Meynet G. Meynet Advection of angular momentum Increase the gradient of angular velocity Shear Instabilities Local conservation Meridionalcirculation Transport of Angular Momentum Transport of Chemical Species

  22. ROTATING MODELS

  23. THE EFFECT OF ROTATION • Progressive reduction of the effective gravity from the pole to the equator • Mixing of core nuclear burning products outward and fresh material inward • Different path in the HRD diagram • Increase of the nuclear burning lifetimes • Increase of the mean molecular weight of the envelope • Different mass loss history • Early entrance in the WR phase  Different mass limits and lifetimes for the various WR stages

  24. THE EFFECT OF ROTATION • Progressive reduction of the effective gravity from the pole to the equator • Mixing of core nuclear burning products outward and pristine material inward • Different path in the HRD diagram • Increase of the nuclear burning lifetimes • Different mass loss history • Early entrance in the WR phase  Different mass limits and lifetimes for the various WR stages

  25. THE EFFECT OF ROTATION • Good fit to WR/O • Discrepancies between predicted and observed WR ratios • Good fit to the WR luminosities

  26. THE EFFECT OF ROTATION NO ROTATION WITH ROTATION OK OK OK Too many SNIb/c predicted

  27. ROTATING MODELS Rotational mixing during core He burning brings continuously fresh He from the outer zones into the convective core substantial reduction of the 12C mass fraction left over by core He burning especially in the less massive stars where this mechanism is more efficient due to their higher He burning lifetimes (80-120 are exceptions)

  28. ROTATING MODELS ....hence the behavior of anygivenrotating star during the more advancedburningstageswillresemblethat of a non rotating star having a higher mass (80-120 exceptions) rotatingmodelsappearmuch more compact compared to the non rotatingones the ironcores are largeraswell and rangebetween MFe=1.7-2.3 M

  29. THE FINAL FATE OF ROTATING MODELS Hydrodynamic models based on induced explosions Substantially larger than the observed value Bright SNIb/c produced by rapid rotation? No neutron stars formed by massive progenitors (contrary to recent observational evidences, see Smartt et al. 2009)

  30. EVOLUTION OF THE ANGULAR MOMENTUM During core H burning the angular momentum transport is dominated by the meridional circulation and by mass loss – the relative efficiency depending on the initial mass From Core He exhaustion onward the evolution of the angular momentum is dominated by the local conservation and by the convective mixing

  31. IMPLICATIONS FOR YOUNG PULSARS AND GRBs If the hydrodynamical simulations are wrong and we assume that all the stars would collapse to a NS with a mass corresponding roughly to the Iron Core Mass and a Radius of 12 Km These models have even much more angular momentum in the collapsing iron core than a neutron star can possibly carry Treatment of angular momentum transport still highly uncertain (advection/diffusion, transport mechanisms and their efficiency)  should be revised Important the role of magnetic field (see Heger et al. 2005)

  32. IMPLICATIONS FOR YOUNG PULSARS AND GRBs If the large angular momenta obtained for the iron cores in this work may pose a problem for pulsars, they are very favorable for the GRBs minimum value needed to make a long GRB by magnetar or collapsarformation (Burrows et al. 2007) These models imply that all WR stars can retain enough angular momentum to produce GRBs, either by magnetar or collapsar formation depending on the final mass. This gives a nearly 1000 times higher ratio of GRBs to SNe than the observationally implied value.

  33. SUMMARY • The inclusion of a more efficient mass lossduring the RSG phase (dustdrivenwind) lowers the maximum mass for SN-IIP from ~ 30 M (oldmodels) to ~ 17 M withoutchanging the maximum mass evolvingas RSG, independent of rotation • The inclusion of rotationreduces the minimum mass thatbecome a WR star from ~ 22 M (non rotatingmodels) to ~ 17 Mand the minimum masses for all the various WR stagesand alsothe minimum mass for SNIb/c from ~ 30 M (non rotatingmodels) to ~ 17 M • - Improve the fit to WR/O and to WR luminosities • - Discrepanciesbetweenpredicted and observed WR ratiosstillremain • - Sharp transition from SNIIP to SNIb - toomanySNIb/c predicted • Rotatingmodels are much more compact and with largerironcoresthan the non rotatingones • - Implications for CCSN explosionsimulations • - Average mass of NS remnantlargerthanobserved • - Lowering of the MNS/BH from 22 to 14 (simulatedexplosionuncertain) • The angularmomentum of the core of rotatingmodelsistoo large: • - NS remnantsrotatingtoo fast • - GRB/SN ratio severelyoverestimated

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