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Nuclear Laboratory Data Needs for Astrophysics

Nuclear Laboratory Data Needs for Astrophysics. S. E. Woosley , Alex Heger, and Rob Hoffman with help from Tuguldur Sukhbold , Justin Brown, Michael Wiescher , Thomas Janka , and Roland Diehl. John Poole and S. Woosley (1983). "There is something fascinating about science.

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Nuclear Laboratory Data Needs for Astrophysics

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  1. Nuclear Laboratory Data Needs for Astrophysics S. E. Woosley, Alex Heger, and Rob Hoffman with help from TuguldurSukhbold, Justin Brown, Michael Wiescher, Thomas Janka, and Roland Diehl John Poole and S. Woosley (1983)

  2. "There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact." Mark Twain and Willy Fowler on many occasions

  3. Today's scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality. - Nikola Tesla

  4. NUCLEAR ASTROPHYSICS • Requirements for nuclear data are very broad and diverse • We want to understand the origin of every isotope • (fortunately not every isotope interacts with every other one!)Three general areas of application: • Nucleosynthesis – Big Bang, Stars, Novae, Supernovae, Cosmic Rays • Energy Generation – Stars, Sun (including neutrinos), Novae, X-Ray Bursts • Behavior of matter at high density and temperature

  5. PROBLEMS PARTICULAR TO NUCLEARASTROPHYSICS • The relevant energies in the stars are generally much lower than what can be accessed in the laboratory • Both product and target nuclei are frequently radioactive (tdecay > tHD) • Targets exist in a thermal distribution of excited states • There are a lot of nuclei and reactions (tens of thousands)

  6. Typical nuclear data deck for stellar nucleosynthesis includes 5442 nuclei and 105,000 reactions (plus their inverses). Fortunately not all areequally important. Most (non-r-process) studies use about 1/3 of this.

  7. SOURCES OF DATA • Laboratory • Stable targets – (underground), low background, high current • Unstable beams – e.g., FAIR/GSI,ISAC/TRIUMF, RIBF/RIKEN, ISOLDE/CERN,ATLAS/ARGONNE, NSCL/MSU,FRIB (to come) • Surrogate reactions, inversereactions, THM, etc. • Theory • Hauser-Feshbach • R-Matrix analysis • Direct capture calculations • Weak interactions as f(T,r) … and tabulations of all data in a refereed machine usable format –

  8. Rate distributions (a partial list): Portal to many collections (ORNL) http://www.nucastrodata.org/datasets.html Univ California rate set http://adg.llnl.gov/Research/RRSN/ The Brussels (NACRE2) rate set http://www.astro.ulb.ac.be/bruslib/ Xu et al (2012) astroph1212.0628 The KADONIS (Karlsruhe) rate set for s- and p-processes http://www.kadonis.org The JINA rate set https://groups.nscl.msu.edu/jina/reaclib/db/ Cyburt et al ApJS 189, 240 (2010) … and many more

  9. Yields averaged over a Salpeter (G = 1.35) initial mass function. Responsible for producing the elements 4 < Z < 39

  10. Isotopic yields for 31 stars averaged over a Salpeter IMF, G = -1.35 Intermediate mass elements (23< A < 60) and s-process (A = 60 – 90) well produced. Carbon and Oxygen over- produced. p-process deficient by a factor of ~4 for A > 130 and absent for A < 130

  11. Lately, we have been testing the JINA rate distributions in stellar and supernova models against our older collection of rates. Four masses of stars 15, 18, 22, and 25 solar masses. Hold structure constant, i.e., use same rates for energy generation, but use new rates for nucleosynthesis. Used JINA 1.0, version 2.0 in progress (many bugs found in JINA 1.0)

  12. Results using new rates Results using old rates

  13. ~fac 2 changes (mostly down) for many (ag) and (a,p) reactions on Ca and Ti 31P being destroyed by larger 31P(p,a)28Si rate

  14. Slight overall increase in s-process (even though 22Ne(a,n)25Mg went up by 20%) due to factor of 4 decrease in 22Ne(a,g)26Mg

  15. New data includes revised partition functions, Q-values, weak decay rates and dozens ofreaction rates. • No very large changes (> factor 2) found yetfor A < 100 nucleosynthesis but study continues. Larger changes expected for r-process and • rp-process synthesis. Switching to JINA 2.0 now. • Abundance determinations in the sun and meteorites is now giving agreement to 10% • for most elements. Commensurate accuracy in the stellar models and nuclear physics desired • Studies like this will help locate regions of uncertainty.

  16. SOME SPECIFIC CURRENT CHALLENGES 12C(a,g)16O (and 3a) – Probably the last remaining uncertain reactions that affect stellar structure as well as nucleosynthesis 22Ne(a,n)25Mg - Main source of neutrons for the s-process. Important diagnostic for which stars actually blow up Reactions affecting the production of 26Al, 44Ti, and 60Fe. Important long lived radioactive gamma-ray line emitters Reactions affecting the rp-process in x-ray bursts andthe r-process of nucleosynthesis (nuclei far from stability) Reactions affecting the solar neutrino flux or Big Bang nucleosynthesis

  17. Oxygen-16 12C ( a, g ) 16O * The relative rates of 3a and 12C(a,g)16O determine the proportions of C and O that come out of helium burning. C and O are fuels for major subsequent burning stages. Low energy data are needed to improve reliability of cross section extrapolation

  18. Heger, Woosley, & Boyse (2002) Obviously 12C(a,g)16O affects the nucleosynthesis 12C and 16O, but it also directly affects the production of many other species made by carbon, neon and oxygen burning. Many species are successfully coproduced if the rate has an S-factor at 300 keV of about 170 keV b But it also affects the structure of the pre- supernovastar uncertainty

  19. Density Profiles of Supernova Progenitor Cores These will be hard to explode. High binding energy. High prompt accretion rate. These should be easy to explode 2D SASI-aided, Neutrino-Driven Explosion?

  20. O’Connor and Ott, ApJ, 730, 70, (2011) Characterize possibility of a neutrino-powered explosion based upon the compactness parameter, z, If R is small and the 2.5 solar mass point lies close in, then z is big. The star is hard to explode. Based upon a series of 1D models OO11 find stars with z over 0.45 are particularly difficult to explode. Ugliano et al, ApJ, 757, 69 (2012) find more diversity and get explosions for a smaller value of x, as low as 0.15

  21. Density Profiles of Supernova Progenitor Cores Large z Small z 2D SASI-aided, Neutrino-Driven Explosion?

  22. Sukhbold and Woosley (in prep) Oconnor and Ott (2011) Harder to explode Strong carbon Burning Shell Convective Carbon Core Burning (exoergic) ~Ugliano et al (2012) Easier to explode

  23. Island of Explodability? Stars with very litle mass loss e.g., low metallicity stars

  24. (Thomas Janka, PTEP, 2012) Shock radius as a function of time for 2D simulations by Janka’s group. All stars but the 25 solar mass model explode – at least initially. This includes 27 solar masses

  25. (calculations by Sukhbold) norm. Buchmann (1996) S(300 keV) = 146 keV b The mass of the maximum mass star that has exoergic carbon core burning as a function of the 12C(a,g)16O rate. The most likely range of the multiplier here is 0.85 to 1.3 (S(300 keV) = 159 +- 20% keV b). That implies an uncertainty in the mass of 3 to 4 solar masses.

  26. 12C ( a, g ) 16O Current situation (S(300 keV)): Buchmann (1996) 146 keV b (range 82 – 270)Buchmann (2005) 145 +- 43 keV b Kunz et al (2001) 165 +- 50 keV b Schuermann (2012) 161+- 16 +8-2 (sys) keV b We use 1.2 * Buchmann = 175 keV b (and have used it for 15 years)

  27. In progress deBoer et al. R-matrix analysis of ~10,000 experimental data points. Success so far for 15N(p,g) and 15N(p,a) Expected accuracy < 10% (Wiescher private communication) 12C(a,g), 12C(a,p), 12C(a,a), 15N(p,g), 15N(p,a), 15N(p,p), and 16N(b-a) including all the various gamma, alpha, and proton decay channels.

  28. Low Energy References

  29. High Energy References

  30. Of equal importance to 12C(a,g)16O is 3a The current uncertainty in 3a is 10%, i.e., beginning to be comparable to the uncertainty in 12C(a,g)16O . Error in one rate compromises the accuracy of the other West, Heger, and Austin (2013 in press) astroph 1212.5513

  31. West, Heger, and Austin (2013) 3a uncertainty dominated by pair width of 0+ resonance

  32. 22Ne(a,n)25Mg and the Heaviest Supernova

  33. 14N(a,g)18O(a,g)22Ne(a,n)25Mg 22Ne burns at the very end of helium burning. If it does not burn to completion or if it burns by 22Ne(a,g)26Mg, then the neutrons are released later in carbon burning when there are abundant neutron poisons like 23Na.The s-process is thus stronger in stars that reach higher temperaturein helium burning, i.e., in more massive stars. The production of the s-process relative to 16O thus depends on the mass of the star. Only the most massive stars make it.

  34. Presupernova stars – Type IIp and II-L Smartt, 2009 ARAA Progenitors heavier than 20 solar masses excluded at the 95% condidence level. The solid line is for a Salpeter IMF with a maximum mass of 16.5 solar masses. The dashed line is a Salpeter IMF with a maximum of 35 solar masses

  35. LOW

  36. Brown and Woosley (2013, submitted)

  37. Brown and Woosley (2013, submitted)

  38. Longland, Iliadis, and Karakis (PRC, 2012) 22Ne(a,g)26Mg 22Ne(a,n)25Mg norm hi x 2

  39. Radioactivities Detected by their Gamma-Ray Lines

  40. Reactions affecting 44Ti(a-rich freeze out) Relevant temperature range T9 = 2 - 4

  41. 40Ca(a,g)44Ti Nassar (2006) Vockenhuber (2008) Hoffman et al (2010) Robertson et al (2012)Considerable variation, esp. H10 vs R12, error ~ 25 - 50%. Hauser Feshbachnot reliable. 44Ti(a,p)47V radioactive beam at TRIUMF (DRAGON) Sonzogni et al (2000) re-evaluated Hoffman et al (2010)

  42. Summary: 40Ca(a,g)44Ti and 44Ti(a,p)47Sc are most critical. The former is now better known thanks to Robertson et al but given the dispersion on past measurements further study may be warranted. The latter is still uncertain to about a factor of two or three for the relevant temperature range. The error in rates could compensate for most of the discrepancy between models and the observed signal without invoking unusual explosion geometry – Hoffman et al (2010)

  43. INTEGRAL OBSERVATIONS OF 26Al (t1/2 = 0.72 My AND 60Fe (t1/2 = 1.5 - 2.6 My) IN THE ISM 60Fe (5 sigma signal) 26Al (32 sigma signal) Brightness Ratio = 0.15 +- 0.04 Necessary mass ratio = (0.15)(60/26) = 0.35

  44. Target 0.35 Timmes, Woosley and Weaver (1995) 0.36 (prediction) Woosley and Heger (2007) new rates and opacities and mass loss 1.8 Woosley and Heger (2007) adjusting only 26Al cross sections using experiment rather than HF 0.95 further changes in 59,60Fe and 22Ne(a,n) could reduce it by as much as 2 0.50?? Meynet, Palacios, Limongi, Chieffi additional effects due to treatment of rotational mixing, convective algorithm, metallicity, mass loss, and IMF.

  45. 60Fe

  46. 60Fe • 60Fe target 7.8 x 1015 atoms - Schumann et al • (NIMPA 2010) - chemical extraction from accelerator waste 60Fe(n,g)61Fe 30 keV 9.9 +- 1.4 +- 2.8 mb measured by activation. Answer sensitive to uncertain t1/2(60Fe) Uberseder et al, PRL, 102, 1101 (2009) 59Fe(n,g)60Fe (t1/2 = 44.5 d) being studied by photodissociation of 60Fe at GSI Uberseder PhD thesis (Notre Dame) just completed. Paper in preparation – “ will be submitted in a few weeks” No big surprises The production of 60Fe is most sensitive to 59Fe(n,g)

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