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Title: High-temperature 205Tl decay clarifies 205Pb dating in early Solar System
Abstract Radioactive nuclei with lifetimes on the order of millions of years can reveal the formation history of the Sun and active nucleosynthesis occurring at the time and place of its birth1,2. Among such nuclei whose decay signatures are found in the oldest meteorites,205Pb is a powerful example, as it is produced exclusively by slow neutron captures (thesprocess), with most being synthesized in asymptotic giant branch (AGB) stars3–5. However, making accurate abundance predictions for205Pb has so far been impossible because the weak decay rates of205Pb and205Tl are very uncertain at stellar temperatures6,7. To constrain these decay rates, we measured for the first time the bound-state β−decay of fully ionized205Tl81+, an exotic decay mode that only occurs in highly charged ions. The measured half-life is 4.7 times longer than the previous theoretical estimate8and our 10% experimental uncertainty has eliminated the main nuclear-physics limitation. With new, experimentally backed decay rates, we used AGB stellar models to calculate205Pb yields. Propagating those yields with basic galactic chemical evolution (GCE) and comparing with the205Pb/204Pb ratio from meteorites9–11, we determined the isolation time of solar material inside its parent molecular cloud. We find positive isolation times that are consistent with the others-process short-lived radioactive nuclei found in the early Solar System. Our results reaffirm the site of the Sun’s birth as a long-lived, giant molecular cloud and support the use of the205Pb–205Tl decay system as a chronometer in the early Solar System.  more » « less
Award ID(s):
1927130
PAR ID:
10649173
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Publisher / Repository:
Nature
Date Published:
Journal Name:
Nature
Volume:
635
Issue:
8038
ISSN:
0028-0836
Page Range / eLocation ID:
321 to 326
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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