New 59Fe Stellar Decay Rate with Implications for the 60Fe Radioactivity in Massive Stars
Abstract
The discrepancy between observations from γ -ray astronomy of the 60Fe / 26Al γ -ray flux ratio and recent calculations is an unresolved puzzle in nuclear astrophysics. The stellar β -decay rate of 59Fe is one of the major nuclear uncertainties impeding us from a precise prediction. The important Gamow-Teller strengths from the low-lying states in 59Fe to the 59Co ground state are measured for the first time using the exclusive measurement of the 59Co (t ,<SUP<3He+γ )59Fe charge-exchange reaction. The new stellar decay rate of 59Fe is a factor of 3.5 ±1.1 larger than the currently adopted rate at T =1.2 GK . Stellar evolution calculations show that the 60Fe production yield of an 18 solar mass star is decreased significantly by 40% when using the new rate. Our result eliminates one of the major nuclear uncertainties in the predicted yield of 60Fe and alleviates the existing discrepancy of the 60Fe / 26Al ratio.
- Publication:
-
Physical Review Letters
- Pub Date:
- April 2021
- DOI:
- 10.1103/PhysRevLett.126.152701
- Bibcode:
- 2021PhRvL.126o2701G