Explosive nucleosynthesis of heavy elements An astrophysical and - PowerPoint PPT Presentation

Explosive nucleosynthesis of heavy elements An astrophysical and nuclear physics challenge Gabriel Martínez Pinedo Nuclear Physics, Compact Stars, and Compact Star Mergers 2016 Mini-workshop on “Compact Star Mergers and Nucleosynthesis” November 9, 2016 Nuclear Astrophysics Virtual Institute

Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary Outline Introduction 1 Nucleosynthesis in supernova neutrino-driven winds 2 Nucleosynthesis in neutron star mergers 3 Dynamical ejecta Accretion disk ejecta Summary 4

Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary Signatures and nucleosynthesis processes Solar system abudances contain signatures of nuclear structure and nuclear stability. They are the result of different nucleosynthesis processes operating in different astrophysical environments and the chemical evolution of the galaxy. Sneden, Cowan & Gallino 2008 a 1.5 Core-collapse Supernovae 1.0 T y p Abundance relative to Silicon = 10 6 e [Mg/Fe] I a H 0.5 10 10 He 0 10 8 CO NeSi S Fe – 0.5 10 6 D Ca Ni 10 4 b 1.5 10 2 Ge Sr Xe Ba Pb 1.0 B Li 10 0 Pt [Eu/Fe] Be r s r s 0.5 10 −2 0 20 40 60 80 100 120 140 160 180 200 220 0 Mass Number – 0.5 –3 –2 –1 0 [Fe/H]

Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary Heavy elements and metal-poor stars Cowan & Sneden, Nature 440 , 1151 (2006) Stars rich in heavy r-process elements ( Z > 50 ) and poor in iron (r-II stars, [Eu / Fe] > 1 . 0 ). 0 0 Robust abundance patter for Z > 50 , Relative log ε −2 −2 consistent with solar r-process abundance. −4 −4 These abundances seem the result of events that do not produce iron. [Qian & Wasserburg, −6 −6 Phys. Rept. 442 , 237 (2007)] −8 −8 Possible Astrophysical Scenario: Neutron star 30 30 40 40 50 50 60 60 70 70 80 80 90 90 Atomic Number mergers. 0.5 (b) Sr Zr 0 translated pattern of CS 22892-052 (Sneden et al. 2003) Ru Stars poor in heavy r-process elements but -0.5 Mo Pd with large abundances of light r-process -1 log ε ( Z ) Y elements (Sr, Y, Zr) -1.5 Nb -2 Production of light and heavy r-process Ag -2.5 elements is decoupled. -3 HD 122563 (Honda et al. 2006) Eu Astrophysical scenario: neutrino-driven -3.5 40 70 80 50 60 winds from core-collapse supernova Atomic Number ( Z ) Honda et al , ApJ 643 , 1180 (2006)

Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary r-process astrophysical sites Neutron star mergers Core-collapse supernova Mergers are expected to eject around Neutrino-winds from 0 . 01 M ⊙ of neutron rich-material. Similar protoneutron stars. amount ejected from accretion disk. Aspherical explosions, Jets, Observational signature: electromagnetic Magnetorotational Supernova, ... [Winteler et al , ApJ 750 , L22 transient from radioactive decay of (2012); Mösta et al , r-process nuclei [KiloNova, Metzger et al arXiv:1403.1230 ] (2010), Roberts et al (2011), Bauswein et al (2013)]

฀ � Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary Role of weak interactions Main processes: ν e + n ⇄ p + e − ν e + p ⇄ n + e + ¯ Neutrino interactions determine the proton to neutron ratio. Neutron-rich ejecta: � � � L ¯ � ν e � E ¯ ν e � − � E ν e � > 4 ∆ np − L ν e − 1 � E ¯ ν e � − 2 ∆ np Neutrino cooling and Neutrino-driven wind 10 5 neutron-rich ejecta: r-process ν e,µ,τ , ν e,µ,τ 10 4 R in km proton-rich ejecta: ν p -process Ni 10 3 Si We need accurate knowledge of ν e and ¯ ν e He 10 2 νp-process spectra – ν e,µ,τ , ν e,µ,τ r-process O R ns ~10 Energy difference related to nuclear R ν PNS symmetry energy (GMP et al 2012, Roberts 1.4 3 α, p α, p, nuclei M ( r ) in M � n, p α, n α, n, nuclei et al 2012)

Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary Constraints in the symmetry energy Combination nuclear physics experiments and astronomical observations (Lattimer & Lim 2013) Isobaric Analog States (Danielewicz & Lee 2013) Chiral Effective Field Theory calculations (Drischler+ 2014) 40 χ EFT (NN+3N), Drischler et al 2014 35 Danielewicz & Lee 2013 IAS Danielewicz & Lee 2013 IAS + Skins Lattimer & Lim 2013 30 DD2 NL3 E sym (MeV) 25 TM1 TMA SFHo 20 SFHx FSUgold 15 IUFSU LS180 10 LS220 5 0 0.01 0.1 n B (fm −3 ) Figure data from Matthias Hempel (Basel)

Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary Impact on neutrino luminosities and Y e evolution 1D Boltzmann transport radiation simulations (artificially induced explosion) for a 11.2 M ⊙ progenitor based on the DD2 EoS (Stefan Typel and Matthias Hempel). Luminosity [ergs/s] 10 52 0 . 60 Electron fraction 0 . 58 0 . 56 0 . 54 10 51 0 . 52 0 . 50 0 . 48 10 50 0 . 46 0 2 4 6 8 10 0 2 4 6 8 10 Time [s] Time [s] Entropy [ k B /baryon] 13 100 90 12 ν e � E ν � [MeV] 80 11 ν e ¯ 70 10 60 ν x 9 50 8 40 7 30 6 20 0 2 4 6 8 10 0 2 4 6 8 10 Time [s] Time [s] Y e is moderately neutron-rich at early times and later becomes proton-rich. GMP, Fischer, Huther, J. Phys. G 41 , 044008 (2014).

Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary Nucleosynthesis 10 7 10 6 11.2 10 5 Rel. abundance 10 4 10 3 10 2 10 1 10 0 10 − 1 10 − 2 10 − 3 10 − 4 50 60 70 80 90 100 110 Mass number A 10 − 2 Elemental abundance 10 − 3 HD 122563 10 − 4 10 − 5 10 − 6 10 − 7 10 − 8 10 − 9 25 30 35 40 45 50 55 Charge number Z Elements between Zn and Mo ( A ∼ 90 ) are produced Mainly neutron-deficient isotopes are produced Uncertainties: Equation of State, neutrino reactions (mainly ¯ ν e ), Neutrino oscillations(?).

Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary Impact opacities on Y e ν e + e − + p → n ) have a strong Weak magnetism and inverse neutron decay ( ¯ impact on Y e Ref. run 80 + weak magn. 0.58 + wm + n decay S [k B /baryon] 0.56 60 Y e 0.54 40 S 0.52 Y 20 e 0.5 0.48 0 0.5 1 2 3 5 10 t − t bounce [s] Fischer, GMP,Wu, Lohs, Qian, in preparation

Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary Neutron star mergers: Short gamma-ray bursts and r-process 30 14.5 30 14.5 14 14 Bauswein, Goriely, Janka, ApJ 773 , 78 (2013) 20 20 13.5 13.5 13 13 10 10 12.5 12.5 y [km] 12 y [km] 12 0 0 11.5 11.5 11 11 −10 −10 10.5 10.5 10 10 −20 −20 9.5 9.5 −30 −30 9 9 −30 −20 −10 0 10 20 30 −30 −20 −10 0 10 20 30 x [km] x [km] 12.1235 ms 12.6867 ms 30 14.5 50 14.5 14 14 40 20 13.5 13.5 30 13 13 10 20 12.5 12.5 y [km] 12 10 0 y [km] 12 11.5 0 11.5 11 −10 −10 11 10.5 −20 10.5 10 −20 −30 10 9.5 −40 9.5 −30 9 −30 −20 −10 0 10 20 30 −50 9 x [km] −50 0 50 13.4824 ms x [km] 15.167 ms Mergers are expected to eject dynamically around 0 . 001 - 0 . 01 M ⊙ of neutron rich-material. Impact of weak interactions remains to be understood.

Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary Dynamical evolution in mergers Dynamics Inspiral of NS binary ~100 Myrs GW → binary masses, EoS Neutron star merger dynamical ejecta dependent on dynamical ejecta EoS, M tot GW → EoS ms ms Prompt formation of a Formation of a differentially BH + torus rotating massive NS dependent on EoS, M tot 10-100 ms secular (disk) ejecta Rigidly rotating Delayed collapse (supermassive) NS to a BH + torus Reviews: Duez 2010, Faber & Rasio 2012 secular (disk) ejecta secular (disk) ejecta From A. Bauswein.

Introduction Nucleosynthesis in supernova neutrino-driven winds Nucleosynthesis in neutron star mergers Summary Neutron star mergers: Short gamma-ray bursts and r-process Fernández & Metzger, 2016 A similar amount of material less neutron rich Y e � 0 . 2 is expected to be ejected from the disk. Conditions and ejection mechanism depend on central object (neutron star or black hole). Both dynamical and disk ejecta may contribute to radioactive electromagnetic transient (kilonova).