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Abstract Many of the short-lived radioactive nuclei that were present in the early solar system can be produced in massive stars. In the first paper in this series, we focused on the production of26Al in massive binaries. In our second paper, we considered rotating single stars; two more short-lived radioactive nuclei,36Cl and41Ca; and the comparison to the early solar system data. In this work, we update our previous conclusions by further considering the impact of binary interactions. We used the MESA stellar evolution code with an extended nuclear network to compute massive (10–80M⊙), binary stars at various initial periods and solar metallicity (Z= 0.014), up to the onset of core collapse. The early solar system abundances of26Al and41Ca can be matched self-consistently by models with initial masses ≥25M⊙, while models with initial primary masses ≥35M⊙can also match36Cl. Almost none of the models provide positive net yields for19F, while for22Ne the net yields are positive from 30M⊙and higher. This leads to an increase by a factor of approximately 4 in the amount of22Ne produced by a stellar population of binary stars, relative to single stars. In addition, besides the impact on the stellar yields, our 10M⊙primary star undergoing Case A mass transfer ends its life as a white dwarf instead of as a core-collapse supernova. This demonstrates that binary interactions can also strongly impact the evolution of stars close to the supernova boundary.
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This content will become publicly available on December 1, 2025
Enhanced production of 60Fe in massive stars
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 as60Fe (iron) and26Al (aluminum), offer unique signs of active nucleosynthesis in our galaxy. There is a long-standing discrepancy between the observed60Fe/26Al ratio by γ-ray telescopes and predictions from supernova models. This discrepancy has been attributed to uncertainties in the nuclear reaction networks producing60Fe, and one reaction in particular, the neutron-capture on59Fe. Here we present experimental results that provide a strong constraint on this reaction. We use these results to show that the production of60Fe in massive stars is higher than previously thought, further increasing the discrepancy between observed and predicted60Fe/26Al ratios. The persisting discrepancy can therefore not be attributed to nuclear uncertainties, and points to issues in massive-star models.
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- PAR ID:
- 10615485
- Author(s) / Creator(s):
- ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
- Publisher / Repository:
- Nature
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 15
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Radioactive nuclei were present in the early solar system (ESS), as inferred from analysis of meteorites. Many are produced in massive stars, either during their lives or their final explosions. In the first paper of this series (Brinkman et al. 2019), we focused on the production of 26 Al in massive binaries. Here, we focus on the production of another two short-lived radioactive nuclei, 36 Cl and 41 Ca, and the comparison to the ESS data. We used the MESA stellar evolution code with an extended nuclear network and computed massive (10–80 M ⊙ ), rotating (with initial velocities of 150 and 300 km s −1 ) and nonrotating single stars at solar metallicity ( Z = 0.014) up to the onset of core collapse. We present the wind yields for the radioactive isotopes 26 Al, 36 Cl, and 41 Ca, and the stable isotopes 19 F and 22 Ne. In relation to the stable isotopes, we find that only the most massive models, ≥60 and ≥40 M ⊙ give positive 19 F and 22 Ne yields, respectively, depending on the initial rotation rate. In relation to the radioactive isotopes, we find that the ESS abundances of 26 Al and 41 Ca can be matched with by models with initial masses ≥40 M ⊙ , while 36 Cl is matched only by our most massive models, ≥60 M ⊙ . 60 Fe is not significantly produced by any wind model, as required by the observations. Therefore, massive star winds are a favored candidate for the origin of the very short-lived 26 Al, 36 Cl, and 41 Ca in the ESS.more » « less
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Abstract There is a wealth of data on live, undecayed60Fe (t1/2= 2.6 Myr) in deep-sea deposits, the lunar regolith, cosmic rays, and Antarctic snow, which is interpreted as originating from the recent explosions of at least two near-Earth supernovae. We use the60Fe profiles in deep-sea sediments to estimate the timescale of supernova debris deposition beginning ∼3 Myr ago. The available data admits a variety of different profile functions, but in all cases the best-fit60Fe pulse durations are >1.6 Myr when all the data is combined. This timescale far exceeds the ≲0.1 Myr pulse that would be expected if60Fe was entrained in the supernova blast wave plasma. We interpret the long signal duration as evidence that60Fe arrives in the form of supernova dust, whose dynamics are separate from but coupled to the evolution of the blast plasma. In this framework, the >1.6 Myr is that for dust stopping due to drag forces. This scenario is consistent with the simulations in Fry et al. (2020), where the dust is magnetically trapped in supernova remnants and thereby confined around regions of the remnant dominated by supernova ejects, where magnetic fields are low. This picture fits naturally with models of cosmic-ray injection of refractory elements as sputtered supernova dust grains and implies that the recent60Fe detections in cosmic rays complement the fragments of grains that survived to arrive on the Earth and Moon. Finally, we present possible tests for this scenario.more » « less
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