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The p-process nucleosynthesis can explain proton-rich isotopes that are heavier than iron, which are observed in the Solar System, but discrepancies still persist and important questions concerning the astrophysical site(s) of the p-process…
The astrophysical origin of the lanthanides is an open question in nuclear astrophysics. Besides the widely studied $s$, $i$, and $r$ processes in moderately-to-strongly neutron-rich environments, an intriguing alternative site for…
We explore heavy element nucleosynthesis in the explosion of massive stars which are triggered by a quark-hadron phase transition during the early post bounce phase of core-collapse supernovae. The present study is based on general…
We examine the Pb and Th abundances in 27 metal-poor stars (-3.1 < [Fe/H] < -1.4) whose very heavy metal (Z > 56) enrichment was produced only by the rapid (r-) nucleosynthesis process. New abundances are derived from HST/STIS, Keck/HIRES,…
Relativistic jets originating from protomagnetar central engines can lead to long duration gamma-ray bursts (GRBs) and are considered potential sources of ultrahigh-energy cosmic rays and secondary neutrinos. We explore the propagation of…
We investigate $r$-process nucleosynthesis in three-dimensional general relativistic magnetohydrodynamic simulations of jet-driven supernovae resulting from rapidly rotating, strongly magnetized core-collapse. We explore the effect of…
The astrophysical environments capable of triggering heavy-element synthesis via rapid neutron capture (the r-process) remain uncertain. While binary neutron star mergers (NSMs) are known to forge r-process elements, certain rare supernovae…
I compare seven actively studied r-process nucleosynthesis scenarios against observed properties of r-process elements in the early Universe, and conclude that the most likely scenario to contribute to the site of elements below the third…
We investigate the impact of asymmetric neutrino-emissions on explosive nucleosynthesis in core-collapse supernovae (CCSNe) of progenitors with a mass range of 9.5 to 25$M_{\odot}$. We perform axisymmetric, hydrodynamic simulations of the…
Nucleosynthesis in early neutrino winds is investigated. Presented is a brief overview of two recent problems of supernova nucleosynthesis. In the first part we investigate the effect of nuclear parameters on the synthesis of Mo92 and Mo94.…
The chemical feedback from stellar winds in low metallicity (Z) environments is key for understanding the evolution of globular clusters and the early Universe. With disproportionate mass lost from the most massive stars (M > 100Msun), and…
We study the efficiency and sensitivity of r-process nucleosynthesis to 18 light-element nuclear reaction rates. We adopt empirical power-law relations to parameterize the reaction sensitivities. We utilize two different hydrodynamic models…
During the evolution of first stars, the CNO elements may emerge on their surfaces due to the mixing processes. Consequently, these stars may have winds driven purely by CNO elements. We study the properties of such stellar winds and…
An r-process scenario with fission but no fission cycling is considered to account for the observed abundance patterns of neutron-capture elements in ultra-metal-poor stars. It is proposed that neutrino reactions play a crucial role in…
We examine r-process nucleosynthesis in a "prompt supernova explosion" from an 8-10 Msun progenitor star, as an alternative scenario to the "neutrino wind" mechanism. In the present model, the progenitor star has formed an…
Stellar rotation at early ages plays a crucial role in the survival of primordial atmospheres around Earth-mass exoplanets. Earth-like planets orbiting fast-rotating stars may undergo complete photoevaporation within the first few hundred…
We present the distributions of elemental abundance ratios using chemodynamical simulations which include four different neutron capture processes: magneto-rotational supernovae, neutron star mergers, neutrino driven winds, and electron…
We present results of a series of magnetohydrodynamic (MHD) and hydro- dynamic (HD) 2.5D simulations of the morphology of outflows driven by nested wide-angle winds - i.e. winds which eminate from a central star as well as from an orbiting…
The dense wind environment (or circumstellar medium) may be ubiquitous for the regular Type II supernovae (SNe) before the explosion, the interaction of which with the SN ejecta could result in a wind breakout event. The shock generated by…
Details of the explosion mechanism of core-collapse supernovae (CCSNe) are not yet fully understood. There is now an increasing number of successful examples of reproducing explosions in the first-principles simulations, which have shown a…