Enhanced production of 60Fe in massive stars

A Spyrou; D Richman; A Couture; C E Fields; S N Liddick; K Childers; B P Crider; P A DeYoung; A C Dombos; P Gastis; M Guttormsen; K Hermansen; A C Larsen; R Lewis; S Lyons; J E Midtbø; S Mosby; D Muecher; F Naqvi; A Palmisano-Kyle; G Perdikakis; C Prokop; H Schatz; M K Smith; C Sumithrarachchi; A Sweet

doi:10.1038/s41467-024-54040-4

Enhanced production of ⁶⁰Fe in massive stars

Nat Commun. 2024 Nov 7;15(1):9608. doi: 10.1038/s41467-024-54040-4.

Authors

A Spyrou^{1

2}, D Richman^{3

4}, A Couture⁵, C E Fields^{5

6}, S N Liddick^{3

7}, K Childers^{3

7}, B P Crider^{3

8}, P A DeYoung⁹, A C Dombos^{3

4}, P Gastis^{5

10}, M Guttormsen¹¹, K Hermansen^{3

4}, A C Larsen¹¹, R Lewis^{3

7}, S Lyons^{3

12}, J E Midtbø¹¹, S Mosby⁵, D Muecher¹³, F Naqvi^{3

14}, A Palmisano-Kyle^{3

4

15}, G Perdikakis¹⁰, C Prokop^{3

5}, H Schatz^{3

4}, M K Smith³, C Sumithrarachchi³, A Sweet¹⁶

Affiliations

¹ Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI, USA. [email protected].
² Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA. [email protected].
³ Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI, USA.
⁴ Department of Physics and Astronomy, Michigan State University, East Lansing, MI, USA.
⁵ Los Alamos National Laboratory, Los Alamos, NM, USA.
⁶ Steward Observatory, University of Arizona, Tucson, AZ, USA.
⁷ Department of Chemistry, Michigan State University, East Lansing, MI, USA.
⁸ Department of Physics and Astronomy, Mississippi State University, Mississippi, MI, USA.
⁹ Department of Physics, Hope College, Holland, MI, USA.
¹⁰ Department of Physics, Central Michigan University, Mount Pleasant, MI, USA.
¹¹ Department of Physics, University of Oslo, Oslo, Norway.
¹² Pacific Northwest National Laboratory, Richland, WA, USA.
¹³ Institut für Kernphysik der Universität zu Köln, Köln, Germany.
¹⁴ Department of Nuclear Engineering, Texas A&M University, College Station, TX, USA.
¹⁵ Physics Department, University of Tennessee, Knoxville, TN, USA.
¹⁶ Lawrence Livermore National Laboratory, Livermore, CA, USA.

Abstract

Massive stars are a major source of chemical elements in the cosmos, ejecting freshly produced nuclei through winds and core-collapse supernova explosions into the interstellar medium. Among the material ejected, long-lived radioisotopes, such as ⁶⁰Fe (iron) and ²⁶Al (aluminum), offer unique signs of active nucleosynthesis in our galaxy. There is a long-standing discrepancy between the observed ⁶⁰Fe/²⁶Al ratio by γ-ray telescopes and predictions from supernova models. This discrepancy has been attributed to uncertainties in the nuclear reaction networks producing ⁶⁰Fe, and one reaction in particular, the neutron-capture on ⁵⁹Fe. Here we present experimental results that provide a strong constraint on this reaction. We use these results to show that the production of ⁶⁰Fe in massive stars is higher than previously thought, further increasing the discrepancy between observed and predicted ⁶⁰Fe/²⁶Al ratios. The persisting discrepancy can therefore not be attributed to nuclear uncertainties, and points to issues in massive-star models.

Abstract

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