The birth environment of the solar system constrained by the relative abundances of the solar radionuclides

Abstract

The relative abundances of the radionuclides in the solar system at the time of its birth are crucial arbiters for competing hypotheses regarding the birth environment of the Sun. The presence of short-lived radionuclides, as evidenced by their decay products in meteorites, has been used to suggest that particular, sometimes exotic, stellar sources were proximal to the Sun's birth environment. The recent confirmation of neutron star - neutron star (NS-NS) mergers and associated kilonovae as potentially dominant sources of r-process nuclides can be tested in the case of the solar birth environment using the relative abundances of the longer-lived nuclides. Critical analysis of the 15 radionuclides and their stable partners for which abundances and production ratios are well known suggests that the Sun formed in a typical massive star-forming region (SFR). The apparent overabundances of short-lived radionuclides (e.g.\, ${}^{26}\mathrm{Al}$, ${}^{41}\mathrm{Ca}$, ${}^{36}\mathrm{Cl}$) in the early solar system appears to be an artifact of a heretofore under-appreciation for the important influences of enrichment by Wolf-Rayet winds in SFRs. The long-lived nuclides (e.g.\, ${}^{238}\mathrm{U}$, ${}^{244}\mathrm{Pu}$, ${}^{247}\mathrm{Cr}$, ${}^{129}\mathrm{I}$) are consistent with an average time interval between production events of $10^8$ years, seemingly too short to be the products of NS-NS mergers alone. The relative abundances of all of these nuclides can be explained by their mean decay lifetimes and an average residence time in the ISM of $\sim 200$ Myr. This residence time evidenced by the radionuclides is consistent with the average lifetime of dust in the ISM and the timescale for converting molecular cloud mass to stars.

9 pages, 2 figures, in press, IAU, Cambridge University Press. arXiv admin note: substantial text overlap with arXiv:1605.07096

References in corpus (10)

• Origin of the heavy elements in binary neutron-star mergers from a gravitational wave event
• A kilonova as the electromagnetic counterpart to a gravitational-wave source
• Nucleosynthesis and Remnants in Massive Stars of Solar Metallicity
• Neutron Star Mergers and Nucleosynthesis of Heavy Elements
• Short-lived Nuclei in the Early Solar System: Possible AGB Sources
• Advanced LIGO Constraints on Neutron Star Mergers and R-Process Sites
• Stellar origin of the 182Hf cosmochronometer and the presolar history of solar system matter
• Inheritance of solar short- and long-lived radionuclides from molecular clouds and the unexceptional nature of the solar system
• Short-lived radioisotopes in meteorites from Galactic-scale correlated star formation
• Triggered Star Formation Inside the Shell of a Wolf-Rayet Bubble as the origin of the Solar System

Cited by in corpus (2)

• A Solar System formation analogue in the Ophiuchus star-forming complex
• Theoretical Distributions of Short-Lived Radionuclides for Star Formation in Molecular Clouds