H. Schatz, September 2012 X-ray bursts X-ray bursts on neutron stars: Most common thermonuclear stellar explosions

Superbursts fuel: deep C rare, hours-days Intermediate long bursts 10s of minutes - hours fuel: deep He? Longer bursts minutes fuel: H, He Short bursts 10 s fuel: He RXTE Galloway et al SLX sec INTEGRAL Falanga 08 RXTE Strohmeyer Open question: How is carbon produced? How can it ignite within a year? Longer vs shorter bursts: Can be explained with nuclear physics from RIB experiments

Open questions Multi-peaked burst rises? Nuclear waiting points? Maurer&Watts U Time (s) Many other open questions: Transition bursts  stable burning with increasing accretion rate Short recurrence time bursts Multi-D effects? Burst oscillations Burst raise Spitkovsky 2002

H. Schatz, September X-ray Bursts Models and Observations  Need nuclear data now to create set of model templates to analyze observations: otherwise match with wrong parameters Major progress in observations MINBAR archive ~5000 widely varying bursts Burst profiles depend on nuclear rates With accurate model templates: Absolute peak flux, distance H/He composition Redshift + color correction (distance and anisotropy independent)  Neutron star compactness Amthor, Cyburt et al Zamfir et al GS Redshift variation

H. Schatz, September Composition of burst nuclear ashes as observable? Absorption edges in X-ray spectrum? Some PRE bursts might bring ashes to the surface: (Weinberg et al. 2001) NASA/Chandra/Wijnands et al. Unknown heat source was added Neutrons drip here? Superfluid? Core? Brown & Cumming 2009 MXB Brown&Cumming 2009 Observations of cooling crusts: -Burst ashes composition sets crust composition -Heating and cooling depend on composition! (Gupta et al. 2007)

Deepest zone of first burst (model zM of Woosley et al. 2007) Model by Heger, Woosley et al.; Similar to other groups: Fisker et al. and Jordi et al. Slowdown creates Burst tails

Nuclear reaction rates matter ! First sensitivity study for full 1D burst model from Heger (Cyburt, Amthor, Keek et al. ) Burst X-ray light curve Final composition of ashes (see also post-processing study by Parikh et al. 2008)

Slid 8 Hendrik Schatz NNPSS 2012, Slide 8 Mass known <10 keV Mass known <100 keV Mass uncertain, half-life known seen Ion Traps ANL, GSI Jyvaskyla Ion Traps ANL, ISOLDE, MSU ORNL  -decay Nuclear Data: Decay studies of 100 Sn, 96 Cd (GSI, MSU RFFS) - Decay data - Masses - Reaction rates Stable: ( 3 He,t) Yale, TUM RIB direct ( ,p)(ANL, ORNL, LLN, CRIB…) Direct (p,  ): (TRIUMF, ORNL) RIB Indirect: (p,p), ANC (ORNL) RIB Indirect (p,d  )/(d,n  ) MSU RIB Indirect Coul. Dis. (RIKEN, GSI) RIB indirect (d,n) FSU Stable: (p,t), ( 4 He, 6 He) (Yale, RCNP) Stable: ( 3 He,n) ND Stable: (ANL) fusion-evaporation-   we are just at the beginning!  ReA3 at NSCL, HELIOS at ANL, ISAC2 at TRIUMF, ESR at GSI  RIBF, FAIR, FRIB, SPIRAL, … Nuc. Theory - predict rates (HF,DC) - Interpret experiments

ReA3/6 Science, Hendrik Schatz, 7/19/2012, Slide 9 Direct p-capture measurements: SECAR method successfully applied at TRIUMF/DRAGON SECAR JENSA SECAR under design (G. Berg, M. Couder) (funded by DOE Office of Science) Inspired by St. George at Notre Dame Large multi-institutional collaboration: (JINA, ANL, CSM, LSU, McMaster, MSU, ND, ORNL, PNNL) Goal: finish design in Fall 2012 Initial measurements possible at ReA3 (but need > ~10 7 pps) 22 Na(p,  ), 23 Mg(p,  ), 25 Al(p,  ) 27 Si(p,  ), 29 P(p,  ), 30 P(p,  ), 33 Cl(p,  ) 34 Cl(p,  ), 34 Ar(p,  ), 37 K(p,  ), 38 K(p,  ) ANASEN AT-TPC Also new opportunities For indirect studies At NSCL/ReA3 and FRIB

FRIB: A Unique Opportunity FRIB only facility offering reaccelerated fragmentation RIBs H. Schatz, September Reaccelerated beams at FRIB: Unique opportunity to remove many major nuclear physics uncertainties for novae and x-ray bursts:  Novae and XRBs first explosive scenarios with nuclear physics on par with stable nuclei scenarios SECAR AT-TPC ANASEN

Summary Nuclear physics in X-ray bursts needs to be understood to explain phenomena, to analyze observations, to extract NS properties Decay rates are known experimentally – need stellar corrections from theory Need additional precision mass measurements near p-drip line Challenge for the Future: Need to measure critical reaction rates -Identify critical rates in wide range of sensitivity studies -Use indirect techniques to identify key resonances and to constrain weak resonances/cross sections that cannot be measured directly (New devices: HELIOS, ANASEN, JENSA, AT-TPC, … ) -Measure critical rates directly at astrophysical energies -Build SECAR -Exploit NSCL ReA3 and develop beams at TRIUMF -Build FRIB – use reaccelerated beams -Evaluation and Dissemination Tackle problems in integrated coordinated approach: various burst types, crust, neutron star properties – nuclear, astrophysics, observations (JINA!)