Understanding the mass distribution of the first generation of massive stars and the yields of individual elements they injected into the intergalactic medium is one of the central questions in modern astrophysics. Among the most powerful observational clues to address this issue are the elemental abundance patterns of extremely metal-poor (EMP) stars. These stars are believed to have formed...
The most metal-poor stars offer a unique window into the chemical enrichment processes driven by Population III stars in the early Universe. The observed chemical abundance patterns in these stars provide critical constraints on the nucleosynthetic yields of metal-free progenitors, shedding light on their zero-age main-sequence masses. In this work, we analyze 406 very metal-poor stars with...
Elements heavier than iron are predominantly formed through neutron-capture processes, the slow (s-process) and rapid (r-process) neutron-capture processes. The s-process occurs in low- and intermediate-mass stars during the Asymptotic giant branch stage, while the r-process takes place under more extreme conditions, such as neutron star or black hole mergers.
Recently, an intermediate...
$^{146}$Sm, as an extinct p-process isotope, plays an irreplaceable role in the time-line construction of the early solar system (ESS) and the geochemical tracing via its α decay to $^{142}$Nd. Persistent debate on both measured and theoretical half-lives of $^{146}$Sm results in a large uncertainty in the initial $^{146}$Sm abundance of the ESS and subsequent dating of planetary events after...
The rapid neutron capture process, known as the $r$-process, is responsible for producing approximately half of the elements heavier than iron, including Ag, Au, Th and U, among others. Despite its fundamental role in nucleosynthesis, the astrophysical sites and conditions of the r-process remain an open question. Metal-poor stars serve as exceptional
laboratories for studying this process,...
One of the prime questions in Galactic archeology is how chemical elements formed in the universe. Whereas the past decades have focused on nucleosynthesis in single stars, more evidence is emerging in favour of exotic systems such as stripped massive binaries, magnetorotating supernovae (MRSNe) and compact binary mergers with GW detectors. In this study, for the first time, we explore...
The nuclear mechanism responsible for roughly half of the heavy-elements (Z>30) abundances in our Solar system---the rapid neutron capture (r) process---was long thought to produce a "universal" abundance pattern. However, recent studies have challenged r-process universality by identifying significant variations between the elemental abundances patterns of metal-poor ([Fe/H]<$-$1.0),...
