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Nuclear physics properties driving neutron star shallow heating and cooling

Nuclear physics properties driving neutron star shallow heating and cooling. Zach Meisel 2016 Ohio University Symposium on Neutron Stars in the Multi-Messenger Era. Accretion on neutron stars drives nuclear reactions. accretion disk atmosphere ocean crust core. neutron star.

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Nuclear physics properties driving neutron star shallow heating and cooling

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  1. Nuclear physics properties driving neutron star shallow heating and cooling Zach Meisel 2016 Ohio University Symposium on Neutron Starsin the Multi-Messenger Era

  2. Accretion on neutron starsdrives nuclear reactions accretion disk atmosphere ocean crust core neutron star accretion disk p,-capture 12C-fusion, e--capture e--capture n-emission/capture, ρ-driven fusion H/He-rich star ~0.01 AU radius F. Mirabel

  3. Astrophysical observables provide a window into NS nuclear processes accretion disk atmosphere ocean crust core X-ray flux F. Haberl et al ApJ 1987 p,-capture 12C-fusion, e--capture e--capture n-emission/capture, ρ-driven fusion 0 5 10 15 20 Hours W. Lewin et al. SSRv 1993 radius X-ray flux 0 10 20 30 40 Seconds

  4. Astrophysical observables provide a window into NS nuclear processes accretion disk atmosphere ocean crust core R. Cornelisse et al. A&A 2000 p,-capture 12C-fusion, e--capture e--capture n-emission/capture, ρ-driven fusion X-ray flux 0 0.5 radius Days

  5. Astrophysical observables provide a window into NS nuclear processes accretion disk atmosphere ocean crust core J. Homan et al. ApJ2014 p,-capture 12C-fusion, e--capture e--capture n-emission/capture, ρ-driven fusion Temperature 10 100 1000 radius Days since accretion turn-off

  6. Cooling transients probe thermal & compositional structure of the neutron star accretion disk atmosphere ocean crust core J. Homan et al. ApJ2014 p,-capture 12C-fusion, e--capture e--capture n-emission/capture, ρ-driven fusion Temperature 10 100 1000 radius Days since accretion turn-off

  7. Buried nuclei undergo electron capture in the degenerate electron gas accretion disk NS surface System Energy Egs(Z-2,A) Egs(Z-1,A) Ee,Fermi density Egs(Z,A) (Z,A)

  8. Buried nuclei undergo electron capture in the degenerate electron gas accretion disk NS surface System Energy Egs(Z-2,A) Egs(Z-1,A) Ee,Fermi density Egs(Z,A) (Z,A)

  9. Buried nuclei undergo electron-capture,causing heat release accretion disk NS surface Ee,Fermi e--Capture heat release System Energy Egs(Z-2,A) Ee,Fermi e--Capture Egs(Z-1,A) density Egs(Z,A) (Z,A)(Z-2,A)

  10. Buried nuclei undergo electron-capture,OR cooling accretion disk NS surface Ee,Fermi e--Capture Egs(Z-2,A) System Energy Ee,Fermi e--Capture Egs(Z-1,A) β- ν ν ν neutrino cooling ν “Urca” process density Egs(Z,A) (Z,A)(Z-1,A) ν

  11. Urca cooling was recently identified in the neutron star crust Z H. Schatz et al. Nature 2014 N

  12. Many more urca cooling pairs exist in the outer layers neutron stars Nuclear cooling luminosity by mass number (A) Depth into NS A. Deibel et al.,Submitted to ApJ

  13. Urca cooling pairs in the outer layers neutron stars may impact observables Altered cooling transient light curve Reduced carbon ignition depth A. Deibel et al., Astrophys. J. Lett. (2015) A. Deibel et al.,Submitted to ApJ

  14. Whether or not heating or cooling occurs depends on nuclear physics Ee,Fermi Ee,Fermi e--Capture e--Capture System Energy Egs(Z-2,A) Ee,Fermi heat release Egs(Z-2,A) Egs(Z-1,A) System Energy Ee,Fermi e--Capture e--Capture Egs(Z-1,A) β- ν neutrino cooling Egs(Z,A) Egs(Z,A) *Cooling is often many times stronger than heating

  15. Impact of Nuclear Physics Properties on Heating/Cooling Nuclear physics property Impact -Heating or cooling? -Location & Strength -Heating or cooling? -Strength Strength of cooling pair Magnitude of heating/cooling • Nuclear masses • Nuclear structure • (excited state energies, spins & parities) • Weak transition rates • (Gamow-Teller strength distributions) • rp-process nuclear reaction rates which influence abundances of Urca pair mass-numbers

  16. Impact of Nuclear Physics Properties on Heating/Cooling Nuclear physics property Impact -Heating or cooling? -Location & strength • Nuclear masses System Energy Egs(Z-2,A) Ee,Fermi heating or cooling Egs(Z-1,A) Ee,Fermi Ee,Fermi e--Capture e--Capture heat release Egs(Z-2,A) System Energy Ee,Fermi e--Capture e--Capture Egs(Z,A) Egs(Z-1,A) β- ν neutrino cooling Egs(Z,A)

  17. Whether heating or cooling could occur for A=56 depended on the mass of 56Sc H. Schatz et al. Nature 2014 v Mass model B Temperature Energy v Mass model A Mass model B ~50% increase Mass model A 56Ti 56Sc 56Ca Depth into NS

  18. Mass measurement of 56Sc by ‘time-of-flight’ Momentum measurement Timing measurement # Events Time-of-flight Coupled Cyclotrons S800 Spectrograph A1900 Fragment Separator Z. Meisel et al., Phys. Rev. Lett.114(2015) Z. Meisel et al., Phys. Rev. Lett. 115(2015) Z. Meisel et al., Phys. Rev. C (2016) Production Target

  19. Weak heating occurs due to A=56 nuclei in neutron stars Conclusion:Weak heating occurs due to A=56 nuclei in neutron stars H. Schatz et al. Nature 2014 v Mass model B Temperature v ~50% increase Mass model A Depth into NS Z. Meisel et al., Phys. Rev. Lett. 115(2015)

  20. Impact of Nuclear Physics Properties on Heating/Cooling Nuclear physics property Impact Nuclear structure (excited state energies, spins & parities) -Heating or cooling? -Location & strength System Energy Egs(Z-2,A) Ee,Fermi heating or cooling Egs(Z-1,A) Ee,Fermi Ee,Fermi e--Capture e--Capture heat release Egs(Z-2,A) System Energy Ee,Fermi e--Capture e--Capture Egs(Z,A) Egs(Z-1,A) β- ν neutrino cooling Egs(Z,A)

  21. Nuclear structure properties for NS crust nuclides presently relies on theory Z. Meisel et al., Phys. Rev. Lett. 115 (2015)

  22. Impact of Nuclear Physics Properties on Heating/Cooling Nuclear physics property Impact Weak transition rates (Gamow-Teller strength distributions) Strength of cooling pairor heating event System Energy Egs(Z-2,A) Ee,Fermi heating or cooling Egs(Z-1,A) Ee,Fermi Ee,Fermi e--Capture e--Capture heat release Egs(Z-2,A) System Energy Ee,Fermi e--Capture e--Capture Egs(Z,A) Egs(Z-1,A) β- ν neutrino cooling Egs(Z,A)

  23. Relevant weak transition rates rely on calculations and approximations C. Sullivan et al. Astrophys. J. ( 2016)

  24. …and some weak transition calculations work better than others S. Noji et al. Phys. Rev. Lett. (2014)

  25. A weak-rate measurement program is ongoing at MSU (RemcoZegers) e.g. 46Ti(t,3He+)S800 Spectrograph+Gretina Gretina -detection Gamma-Ray Energy Tracking In-beam Nuclear Array 3He ejectiles S800 3H (100 MeV/u) ~10M pps target (~10 mg/cm2) Works on stable nuclei only! Nuclear Physics of NS Urca Cooling Zach Meisel25

  26. Impact of Nuclear Physics Properties on Heating/Cooling Nuclear physics property Impact rp-process reaction rates(which influence most important A) Magnitude of possible heating or cooling System Energy Egs(Z-2,A) Ee,Fermi heating or cooling Egs(Z-1,A) Ee,Fermi Ee,Fermi e--Capture e--Capture heat release Egs(Z-2,A) System Energy Ee,Fermi e--Capture e--Capture Egs(Z,A) Egs(Z-1,A) β- ν neutrino cooling Egs(Z,A)

  27. Nuclear physics uncertainties have a large impact on the burst light-curves and ‘ash’ composition Experimental work is needed near & far from stability large impact on x-ray burst light-curve large impact on x-ray burst ‘ash’ composition (a.k.a. Neutron star surface abundances) R. Cyburt et al. Submitted to ApJ

  28. Urca cooling pair abundances vary up to x100 for a single XRB rate variation Strong nuclear coolers affected by 59Cu(p,γ) * * * * * * * * * * * * * * * * * R. Cyburt et al. Submitted to ApJ

  29. Reaction rates of interest can be measured indirectly & directly, e.g. 30S(α,p)33Cl • Study reaction directly with JENSA or ANASEN at MSU • Need higher beam intensities (FRIB) • Once SECAR online, can directly measure important p,γ • Identify important compound nucleus properties via nucleon transfer • e.g. 36Ar(p,t)34Ar at RCNP (S. O’brien et al. AIP Conf. Proc. 2009) • e.g. 32S(3He,n)34Ar at Ohio U.

  30. Can use indirect reaction techniquesto determine structure of compound nuclei Example: Study 30S(α,p) compound nucleus 34Ar via 32S(3He,n) CAKE @ iThemba Laboratory reaction Astrophysical reaction 3He 30S + α 33Cl + p 34Ar 34Ar + n 3He + 32S target Rate = n charged particle

  31. Will soon be able to measure reactions directly Study radiative capture with recoil separators St. George @ Notre Dame SECAR @ ReA3 (Mich. St.) First (p,γ) reactions expected 2019 First (α,γ) reactions expected late 2016 Study (α,p) with stand-alone JENSA (or ANASEN) at ReA3

  32. Many necessary experimental efforts remain to constrain shallow NS nuclear heating & cooling rp-process Masses Structure Reaction rates Weak transition rates NS-crust processes

  33. JINA-CEE* is an ideal hub for coordinating our efforts *Joint Institute for Nuclear Astrophysics - Center for the Evolution of the Elements

  34. Thanks to my collaborators: Starting Aug. 2016 Central Michigan University: Alfredo Estradé, Georgios Perdikakis Institut fürAngewandtePhysik: Christoph Langer Max-Planck-InstitutfürKernphysik: Sebastian George McGill University: Andrew Cumming Michigan State University: Tony Ahn, Alex Brown, Ed Brown, Justin Browne,Richard Cyburt, Alex Deibel, Alexandra Gade, Wei Jia Ong,Wolfgang Mittig, Fernando Montes, Jorge Pereira, Hendrik Schatz, RemcoZegers University of Notre Dame: ManoëlCouder, GwenaelleGilardy, Ed Lamere, Luis Morales, Mike Moran, Chris Seymour, Ed Stech, Michael Wiescher Western Michigan University: Mike Famiano

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