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Multimessenger observations of the neutron star merger GW170817 and its kilonova proved that neutron star mergers can synthesize large quantities of r-process elements. If neutron star mergers in fact dominate all r-process element…

High Energy Astrophysical Phenomena · Physics 2019-09-11 Alexander P. Ji , Maria R. Drout , Terese T. Hansen

Neutron captures produce the vast majority of abundances of elements heavier than iron in the Universe. Beyond the classical slow (s) and rapid (r) processes, there is observational evidence for neutron-capture processes that operate at…

Solar and Stellar Astrophysics · Physics 2025-11-11 Maria Lugaro , Marco Pignatari , René Reifarth , Michael Wischer

The astrophysical site or sites responsible for the r-process of nucleosynthesis still remains an enigma. Since the rare earth region is formed in the latter stages of the r-process it provides a unique probe of the astrophysical conditions…

Solar and Stellar Astrophysics · Physics 2012-02-09 M. Mumpower , G. McLaughlin , R. Surman

The elemental abundances between strontium and silver ($Z = 38-47$) observed in the atmospheres of very metal-poor stars (VMP) in the Galaxy may contain the fingerprint of the weak $r$-process and $\nu p$-process occurring in early…

High Energy Astrophysical Phenomena · Physics 2023-12-20 A. Psaltis , M. Jacobi , F. Montes , A. Arcones , C. J. Hansen , H. Schatz

The astrophysical nature of r-process sites is a long standing mystery and many probable sources have been suggested in the past, among them lower-mass core-collapse supernovae (in the range 8 - 10 Msol), higher-mass core-collapse…

Astrophysics · Physics 2009-11-10 D. Argast , M. Samland , F. -K. Thielemann , Y. -Z. Qian

The rapid neutron-capture process (r-process) is responsible for the creation of roughly half of the elements heavier than iron, including precious metals like silver, gold, and platinum, as well as radioactive elements such as thorium and…

Solar and Stellar Astrophysics · Physics 2025-07-14 Avrajit Bandyopadhyay , Timothy C. Beers

From newly-obtained high-resolution, high signal-to-noise ratio spectra the abundances of the elements La and Eu have been determined over the stellar metallicity range -3<[Fe/H]<+0.3 in 159 giant and dwarf stars. Lanthanum is predominantly…

Astrophysics · Physics 2009-11-10 J. Simmerer , C. Sneden , J. J. Cowan , J. Collier , V. M. Woolf , J. E. Lawler

(Abridged) The stellar sites and the complete mechanism of r-process nucleosynthesis are still unresolved issues. From consideration of the observed abundances in metal-poor stars, it is proposed that the production of the heavy r-process…

Astrophysics · Physics 2009-11-07 Y. -Z. Qian , G. J. Wasserburg

We examine nucleosynthesis in the ejecta of black hole-neutron star mergers based on the results of long-term neutrino-radiation-magnetohydrodynamics simulations for the first time. We find that the combination of dynamical and post-merger…

High Energy Astrophysical Phenomena · Physics 2025-02-06 Shinya Wanajo , Sho Fujibayashi , Kota Hayashi , Kenta Kiuchi , Yuichiro Sekiguchi , Masaru Shibata

Here, we delineate a comprehensive abundance analysis of four $r$-process enhanced metal-poor stars observed with HORuS spectrograph on a 10-m class telescope, GTC. The high signal-to-noise ratio at $R \approx 25000$ spectral resolution…

Solar and Stellar Astrophysics · Physics 2023-08-10 Pallavi Saraf , Thirupathi Sivarani

Elements in the range 37 < Z < 47 provide key information on their formation process. Several studies have shown that some of these elements are formed by an r-process, that differs from the main r-process creating europium. Through a…

Solar and Stellar Astrophysics · Physics 2012-12-20 Camilla Juul Hansen

The effect of rotation of a star on the distribution of chemical species in radiative zones is discussed. Gravity darkening generates a large radiative force on heavy element ions which is directed toward the equatorial plane. Taking iron…

Astrophysics · Physics 2007-05-23 John M. Porter

The chemical abundances of elements such as barium and the lanthanides are essential to understand the nucleosynthesis of heavy elements in the early Universe as well as the contribution of different neutron capture processes (for example…

The dominant site of production of $r$-process elements remains unclear despite recent observations of a neutron star merger. Observational constraints on the properties of the sites can be obtained by comparing $r$-process abundances in…

Astrophysics of Galaxies · Physics 2021-06-16 Tadafumi Matsuno , Yutaka Hirai , Yuta Tarumi , Kenta Hotokezaka , Masaomi Tanaka , Amina Helmi

We present a review of the possible sources for r-process nuclei. It is known that there is as yet no self-consistent mechanism to provide abundant neutrons for a robust r-process in the neutrino-driven winds from nascent neutron stars. We…

Astrophysics · Physics 2010-11-11 Y. -Z. Qian , G. J. Wasserburg

Heavy elements are synthesized by the r-process in neutron star mergers and potentially in rare supernovae linked to strong magnetic fields. Expensive hydrodynamic simulations of these extreme environments are usually post-processed to…

High Energy Astrophysical Phenomena · Physics 2025-06-03 Jan Kuske , Almudena Arcones , Moritz Reichert

A long-standing scientific puzzle has been to explain the origin of the heaviest elements in the Universe and, more particularly, the production of the elements heavier than iron up to uranium. The rapid neutron capture process (or…

High Energy Astrophysical Phenomena · Physics 2023-03-14 Ina K. B. Kullmann

A large star-to-star variation in the abundances of r-process elements, as seen in the [Eu/Fe] ratio for Galactic halo stars, is a prominent feature that is distinguishable from other heavy elements. It is, in part, caused by the presence…

Astrophysics of Galaxies · Physics 2020-02-12 Takuji Tsujimoto , Nobuya Nishimura , Koutarou Kyutoku

Neutrinos from dense environments are connected to the longstanding open questions of how massive stars explode and what are the sites where $r$-process elements are made. Flavor evolution and neutrino properties can influence…

High Energy Physics - Phenomenology · Physics 2021-10-19 Volpe Maria Cristina

Nuclear masses play a fundamental role in understanding how the heaviest elements in the Universe are created in the $r$-process. We predict $r$-process nucleosynthesis yields using neutron capture and photodissociation rates that are based…

Nuclear Theory · Physics 2016-03-30 Dirk Martin , Almudena Arcones , Witold Nazarewicz , Erik Olsen