High-temperature $^{205}$Tl decay clarifies $^{205}$Pb dating in early Solar System
Creators: name: Leckenby, Guy
name: Sidhu, Ragandeep Singh
name: Chen, Ruiyong
name: Mancino, Riccardo
name: Szányi, Balázs
name: Bai, Mei
name: Battino, Umberto
name: Blaum, Klaus
name: Brandau, Carsten
name: Cristallo, Sergio
name: Dickel, Timo
name: Dillmann, Iris
name: Dmytriiev, Dmytro
name: Faestermann, Thomas
name: Forstner, Oliver
name: Franczak, Bernhard
name: Geissel, Hans
name: Gernhäuser, Roman
name: Glorius, Jan
name: Griffin, Chris
name: Gumberidze, Alexandre
name: Haettner, Emma
name: Hillenbrand, Pierre-Michel
name: Karakas, Amanda
name: Kaur, Tejpreet
name: Korten, Wolfram
name: Kozhuharov, Christophor
name: Kuzminchuk, Natalia
name: Langanke, Karlheinz
name: Litvinov, Sergey
name: Litvinov, Yuri A.
name: Lugaro, Maria
name: Martínez-Pinedo, Gabriel
name: Menz, Esther
name: Meyer, Bradley
name: Morgenroth, Tino
name: Neff, Thomas
name: Nociforo, Chiara
name: Petridis, Nikolaos
name: Pignatari, Marco
name: Popp, Ulrich
name: Purushothaman, Sivaji
name: Reifarth, René
name: Sanjari, Shahab
name: Scheidenberger, Christoph
name: Spillmann, Uwe
name: Steck, Markus
name: Stöhlker, Thomas
name: Tanaka, Yoshiki K.
name: Trassinelli, Martino
name: Trotsenko, Sergiy
name: Varga, László
name: Vescovi, Diego
name: Wang, Meng
name: Weick, Helmut
name: Yagüe Lopéz, Andrés
name: Yamaguchi, Takayuki
name: Zhang, Yuhu
name: Zhao, Jianwei
Publisher: name: Deutsches Elektronen-Synchrotron, DESY, Hamburg
Year: 2024
Subjects: subject: 500

description: 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 birth$^{1,2}$. Among such nuclei whose decay signatures are found in the oldest meteorites, $^{205}$Pb is a powerful example, as it is produced exclusively by slow neutron captures (the s process), with most being synthesized in asymptotic giant branch (AGB) stars$^{3–5}$. However, making accurate abundance predictions for $^{205}$Pb has so far been impossible because the weak decay rates of $^{205}$Pb and $^{205}$Tl are very uncertain at stellar temperatures$^{6,7}$. To constrain these decay rates, we measured for the first time the bound-state β$^{−}$ decay of fully ionized $^{205}$Tl$^{81+}$, an exotic decay mode that only occurs in highly charged ions. The measured half-life is 4.7 times longer than the previous theoretical estimate$^{8}$ and our 10% experimental uncertainty has eliminated the main nuclear-physics limitation. With new, experimentally backed decay rates, we used AGB stellar models to calculate $^{205}$Pb yields. Propagating those yields with basic galactic chemical evolution (GCE) and comparing with the $^{205}$Pb/$^{204}$Pb ratio from meteorites$^{9–11}$, we determined the isolation time of solar material inside its parent molecular cloud. We find positive isolation times that are consistent with the other s-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 the $^{205}$Pb–$^{205}$Tl decay system as a chronometer in the early Solar System.