Classical-NOVA CONTRIBUTION to the Milky Way's ²⁶Al abundance: exit channel of the key ²⁵Al(p,γ) ²⁶Si resonance

M B Bennett; C Wrede; K A Chipps; J José; S N Liddick; M Santia; A Bowe; A A Chen; N Cooper; D Irvine; E McNeice; F Montes; F Naqvi; R Ortez; S D Pain; J Pereira; C Prokop; J Quaglia; S J Quinn; S B Schwartz; S Shanab; A Simon; A Spyrou; E Thiagalingam

doi:10.1103/PhysRevLett.111.232503

Classical-NOVA CONTRIBUTION to the Milky Way's ²⁶Al abundance: exit channel of the key ²⁵Al(p,γ) ²⁶Si resonance

Phys Rev Lett. 2013 Dec 6;111(23):232503. doi: 10.1103/PhysRevLett.111.232503. Epub 2013 Dec 4.

Authors

M B Bennett¹, C Wrede², K A Chipps³, J José⁴, S N Liddick⁵, M Santia¹, A Bowe⁶, A A Chen⁷, N Cooper⁸, D Irvine⁷, E McNeice⁷, F Montes⁹, F Naqvi⁸, R Ortez², S D Pain¹⁰, J Pereira⁹, C Prokop⁵, J Quaglia¹¹, S J Quinn¹², S B Schwartz¹³, S Shanab¹, A Simon⁹, A Spyrou¹², E Thiagalingam⁷

Affiliations

¹ Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA.
² Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Department of Physics, University of Washington, Seattle, Washington 98195, USA.
³ Department of Physics, Colorado School of Mines, Golden, Colorado 08401, USA.
⁴ Departament Física i Enginyeria Nuclear (UPC) and Institut d'Estudis Espacials de Catalunya (IEEC), E-08034 Barcelona, Spain.
⁵ National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
⁶ Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Physics Department, Kalamazoo College, Kalamazoo, Michigan 49006, USA.
⁷ Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada.
⁸ Department of Physics and Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520, USA.
⁹ National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA.
¹⁰ Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
¹¹ National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA and Department of Electrical Engineering, Michigan State University, East Lansing, Michigan 48824, USA.
¹² Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA.
¹³ Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Geology and Physics Department, University of Southern Indiana, Evansville, Indiana 47712, USA.

PMID: 24476263
DOI: 10.1103/PhysRevLett.111.232503

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.