Classical-Nova Contribution to the Milky Way’sAl26Abundance: Exit Channel of the KeyAl25(p,γ)Si26Resonance Academic Article uri icon

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abstract

  • Classical novae are expected to contribute to the 1809-keV Galactic γ-ray emission by producing its precursor 26Al, but the yield depends on the thermonuclear rate of the unmeasured 25Al(p,γ)26Si reaction. Using the β decay of 26P to populate the key J(π)=3(+) resonance in this reaction, we report the first evidence for the observation of its exit channel via a 1741.6±0.6(stat)±0.3(syst)  keV primary γ ray, where the uncertainties are statistical and systematic, respectively. By combining the measured γ-ray energy and intensity with other experimental data on 26Si, we find the center-of-mass energy and strength of the resonance to be E(r)=414.9±0.6(stat)±0.3(syst)±0.6(lit.)  keV and ωγ=23±6(stat)(-10)(+11)(lit.)  meV, respectively, where the last uncertainties are from adopted literature data. We use hydrodynamic nova simulations to model 26Al production showing that these measurements effectively eliminate the dominant experimental nuclear-physics uncertainty and we estimate that novae may contribute up to 30% of the Galactic 26Al.

authors

  • Bennett, MB
  • Wrede, C
  • Chipps, KA
  • José, J
  • Liddick, SN
  • Santia, M
  • Bowe, A
  • Chen, Alan
  • Cooper, N
  • Irvine, D
  • McNeice, E
  • Montes, F
  • Naqvi, F
  • Ortez, R
  • Pain, SD
  • Pereira, J
  • Prokop, C
  • Quaglia, J
  • Quinn, SJ
  • Schwartz, SB
  • Shanab, S
  • Simon, A
  • Spyrou, A
  • Thiagalingam, E

publication date

  • December 6, 2013