Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel Nuclear physics properties driving neutron star shallow heating and cooling Zach Meisel 2016 Ohio University Symposium on Neutron Stars in the Multi-Messenger Era

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 2 Accretion on neutron stars drives nuclear reactions H/He-rich star neutron star accretion disk ~0.01 AU accretion disk atmosphere ocean crust core F. Mirabel radius

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 3 Astrophysical observables provide a window into NS nuclear processes accretion disk atmosphere ocean crust core F. Haberl et al ApJ 1987 radius W. Lewin et al. SSRv 1993 Seconds X-ray flux  Hours

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 4 Astrophysical observables provide a window into NS nuclear processes accretion disk atmosphere ocean crust core radius R. Cornelisse et al. A&A 2000 Days X-ray flux 

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 5 Astrophysical observables provide a window into NS nuclear processes accretion disk atmosphere ocean crust core radius Temperature  Days since accretion turn-off J. Homan et al. ApJ 2014

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 6 accretion disk atmosphere ocean crust core radius Temperature  Days since accretion turn-off J. Homan et al. ApJ 2014 Cooling transients probe thermal & compositional structure of the neutron star

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 7 Buried nuclei undergo electron capture in the degenerate electron gas accretion disk NS surface density (Z,A) System Energy E gs (Z,A) E gs (Z-1,A) E gs (Z-2,A) E e,Fermi

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 8 accretion disk NS surface density (Z,A) System Energy E gs (Z,A) E gs (Z-1,A) E gs (Z-2,A) E e,Fermi Buried nuclei undergo electron capture in the degenerate electron gas

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 9 Buried nuclei undergo electron-capture, causing heat release accretion disk NS surface density (Z,A)  (Z-2,A) System Energy E gs (Z,A) E gs (Z-1,A) E gs (Z-2,A) E e,Fermi heat release e - -Capture

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 10 Buried nuclei undergo electron-capture, OR cooling accretion disk NS surface density (Z,A)  (Z-1,A) System Energy E gs (Z,A) E gs (Z-1,A) E gs (Z-2,A) E e,Fermi e - -Capture β-β- neutrino cooling ν ν ν ν e - -Capture “Urca” process ν

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 11 Urca cooling was recently identified in the neutron star crust H. Schatz et al. Nature 2014 Z N

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 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

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 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

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 14 Whether or not heating or cooling occurs depends on nuclear physics System Energy E gs (Z,A) E gs (Z-1,A) E gs (Z-2,A) E e,Fermi e - -Capture β-β- neutrino cooling ν System Energy E gs (Z,A) E gs (Z-1,A) E gs (Z-2,A) E e,Fermi heat release e - -Capture *Cooling is often many times stronger than heating

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 15 Impact of Nuclear Physics Properties on 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 Nuclear physics property Impact -Heating or cooling? -Location & Strength -Heating or cooling? -Strength Strength of cooling pair Magnitude of heating/cooling

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 16 Impact of Nuclear Physics Properties on Heating/Cooling Nuclear masses Nuclear physics property Impact -Heating or cooling? -Location & strength System Energy E gs (Z,A) E gs (Z-1,A) E gs (Z-2,A) E e,Fermi e - -Capture β-β- neutrino cooling ν System Energy E gs (Z,A) E gs (Z-1,A) E gs (Z-2,A) E e,Fermi heat release e - -Capture heating or cooling

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

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 18 Mass measurement of 56 Sc by ‘time-of- flight’ 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) Coupled Cyclotrons A1900 Fragment Separator Production Target S800 Spectrograph Timing measurement Momentum measurement # Events Time-of-flight

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

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

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 21 Nuclear structure properties for NS crust nuclides presently relies on theory Z. Meisel et al., Phys. Rev. Lett. 115 (2015)

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 22 Impact of Nuclear Physics Properties on Heating/Cooling Weak transition rates (Gamow-Teller strength distributions) Nuclear physics property Impact Strength of cooling pair or heating event System Energy E gs (Z,A) E gs (Z-1,A) E gs (Z-2,A) E e,Fermi e - -Capture β-β- neutrino cooling ν System Energy E gs (Z,A) E gs (Z-1,A) E gs (Z-2,A) E e,Fermi heat release e - -Capture heating or cooling

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 23 Relevant weak transition rates rely on calculations and approximations C. Sullivan et al. Astrophys. J. ( 2016)

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 24 …and some weak transition calculations work better than others S. Noji et al. Phys. Rev. Lett. (2014)

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 25 A weak-rate measurement program is ongoing at MSU (Remco Zegers) Nuclear Physics of NS Urca Cooling Zach Meisel 25 3 H (100 MeV/u) ~10M pps target (~10 mg/cm 2 ) 3 He ejectiles S800 Gretina  -detection e.g. 46 Ti(t, 3 He+  ) S800 Spectrograph+Gretina Gamma-Ray Energy Tracking In-beam Nuclear Array Works on stable nuclei only!

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

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

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 28 Urca cooling pair abundances vary up to x100 for a single XRB rate variation Strong nuclear coolers affected by 59 Cu(p, γ ) * * * * * * * * * * * * R. Cyburt et al. Submitted to ApJ * * * * *

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 29 Reaction rates of interest can be measured indirectly & directly, e.g. 30 S( α, p ) 33 Cl 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. 36 Ar(p,t) 34 Ar at RCNP (S. O’brien et al. AIP Conf. Proc. 2009) e.g. 32 S( 3 He,n) 34 Ar at Ohio U.

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 30 3 He target n Example: Study 30 S(α,p) compound nucleus 34 Ar via 32 S( 3 He,n) charged particle Laboratory reaction 3 He + 32 S 34 Ar 30 S + α 34 Ar + n 33 Cl + p Astrophysical reaction Rate = Can use indirect reaction techniques to determine structure of compound nuclei iThemba

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 31 Will soon be able to measure reactions directly St. Notre Dame ReA3 (Mich. St.) First ( α,γ ) reactions expected late 2016 First (p,γ ) reactions expected 2019 Study radiative capture with recoil separators Study ( α,p) with stand-alone JENSA (or ANASEN) at ReA3

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 32 Many necessary experimental efforts remain to constrain shallow NS nuclear heating & cooling rp-process NS-crust processes Masses Structure Reaction rates Weak transition rates

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 33 *Joint Institute for Nuclear Astrophysics - Center for the Evolution of the Elements JINA-CEE * is an ideal hub for coordinating our efforts

Nuclear Physics of NS Shallow Heating/Cooling Zach Meisel 34 Thanks to my collaborators: Starting Aug Central Michigan University: Alfredo Estradé, Georgios Perdikakis Institut für Angewandte Physik: Christoph Langer Max-Planck-Institut für Kernphysik: 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, Remco Zegers University of Notre Dame: Manoël Couder, Gwenaelle Gilardy, Ed Lamere, Luis Morales, Mike Moran, Chris Seymour, Ed Stech, Michael Wiescher Western Michigan University: Mike Famiano