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Galactic chemical evolution of radioactive isotopes

Côté, Benoit; Lugaro, Maria; Reifarth, Rene; Pignatari, Marco; Világos, Blanka; Yagüe, Andrés; Gibson, Brad K.

Authors

Benoit Côté benoit.cote@csfk.mta.hu

Maria Lugaro

Rene Reifarth

Blanka Világos

Andrés Yagüe

Abstract

The presence of short-lived (∼ Myr) radioactive isotopes in meteoritic inclusions at the time of their formation represents a unique opportunity to study the circumstances that led to the formation of the Solar System. To interpret these observations we need to calculate the evolution of radioactive-to-stable isotopic ratios in the Galaxy. We present an extension of the open-source galactic chemical evolution codes NuPyCEE and JINAPyCEE that enables to track the decay of radioactive isotopes in the interstellar medium. We show how the evolution of isotopic ratio depends on the star formation history and efficiency, star-togas mass ratio, and galactic outflows. Given the uncertainties in the observations used to calibrate our model, our predictions for isotopic ratios at the time of formation of the Sun are uncertain by a factor of 3.6. At that time, to recover the actual radioactive-to-stable isotopic ratios predicted by our model, one can multiply the steady-state solution (see Equation 1) by 2.3 +3.4 −0.7. However, in the cases where the radioactive isotope has a half-life longer than ∼ 200 Myr, or the target radioactive or stable isotopes have mass-and/or metallicity-depended production rates, or they originate from different sources with different delay-time distributions, or the reference isotope is radioactive, our codes should be used for more accurate solutions. Our preliminary calculations confirm the dichotomy between radioactive nuclei in the early Solar System with r-and s-process origin, and that 55 Mn and 60 Fe can be explained by galactic chemical evolution, while 26 Al cannot.

Journal Article Type Article
Publication Date Jun 25, 2019
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 878
Issue 2
Article Number 156
Institution Citation Côté, B., Lugaro, M., Reifarth, R., Pignatari, M., Világos, B., Yagüe, A., & Gibson, B. K. (2019). Galactic chemical evolution of radioactive isotopes. The Astrophysical journal, 878(2), https://doi.org/10.3847/1538-4357/ab21d1
DOI https://doi.org/10.3847/1538-4357/ab21d1
Keywords Space and Planetary Science; Astronomy and Astrophysics
Publisher URL https://iopscience.iop.org/article/10.3847/1538-4357/ab21d1

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