相关论文: Advances in r-Process Nucleosynthesis

Investigations of elemental abundances in the ancient and most metal deficient stars are extremely important because they serve as tests of variable nucleosynthesis pathways and can provide critical inferences of the type of stars that…

Results from observations report a growing number of metal-poor stars showing an abundance pattern midway between the s- and r-processes. These so-called r/s-stars raise the need for an intermediate neutron capture process (i-process),…

Some metal-poor stars have abundance patterns which are midway between the slow (s) and rapid (r) neutron capture processes. We show that the helium shell of a fast rotating massive star experiencing a jet-like explosion undergoes two…

The isotopic abundances of r-process elements in the solar system are traditionally derived as residuals from the subtraction of s-process contributions from total solar abundances. However, the uncertainties in s-process nucleosynthesis --…

Whereas light element abundance variations are a hallmark of globular clusters, there is little evidence for variation in neutron-capture elements. A significant exception is M15, which shows a star-to-star dispersion in neutron-capture…

For the origin of heavy r-process elements, different sources have been proposed, e.g., core-collapse supernovae or neutron star mergers. Old metal-poor stars carry the signature of the astrophysical source(s). Among the elements dominantly…

Growing interests in the chemical feature of r-process elements among nearby disk stars represented by the [Eu/Fe] vs. [Fe/H] diagram have sprouted since it can assess the origin of r-process elements through the comparison with theoretical…

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…

Recent studies suggest that binary neutron star (NS-NS) mergers robustly produce the heavy r-process nuclei above the atomic mass number A ~ 130 because of their ejecta consisting of almost pure neutrons (electron fraction of Y_e < 0.1).…

We propose a new neutron-capture site in early metal-poor and metal-free stars of $\sim 20$--$30 \,\mathrm{M}_\odot$ that results from proton ingestion in the He shell during late stages of the stars' lives. Most of the neutron capture…

Carbon-enhanced metal-poor (CEMP) r/s-stars show surface-abundance distributions characteristic of the so-called intermediate neutron capture process (i-process) of nucleosynthesis. We previously showed that the ingestion of protons in the…

We study the abundance patterns and the radial gradients of s-process elements (Y, Zr, Ba, La and Ce), r-process elements (Eu) and mixed-process elements (Mo, Nd and Pr) in the Galactic thin disc by means of a detailed two-infall chemical…

Our aim is to measure accurate, homogeneous neutron-capture element abundances for the sample of 32 EMP giant stars studied earlier in this series, including 22 stars with [Fe/H] $< -$3.0. Based on high-resolution, high S/N spectra from the…

We revisit the abundances of neutron-capture elements in the metal-poor ([Fe/H]=-2.9) r-process-rich halo star CS 31082-001. Partly motivated by the development of the new near-ultraviolet Cassegrain U-band Efficient Spectrograph for the…

The oldest stars in the universe retain to a great extent detailed information on the chemical composition of the interstellar medium at the time of their birth. Hence the earliest phases of Galactic chemical evolution and nucleosynthesis…

Extensive progress has been recently made into our understanding of heavy element production via the $r$-process in the Universe, specifically with the first observed neutron star binary merger (NSBM) event associated with the gravitational…

Context. Thanks to the heroic observational campaigns carried out in recent years we now have large samples of metal-poor stars for which measurements of detailed abundances exist. [...] These data hold important clues on the nature of the…

We explore changes in abundance patterns that occur late in the r process. As the neutrons available for capture begin to disappear, a quasiequilibrium funnel shifts material into the large peaks at A=130 and A=195, and into the rare-earth…

The chemical evolution of the Galaxy is followed for the elements affected by neutron capture, in particular for those in the atomic number range 56 to 63 (Ba, La, Ce, Pr, Nd, Sm and Eu). Neutrons by the major 13^C source, released in…

We examine electron-capture supernovae (ECSNe) as sources of elements heavier than iron in the solar system and in Galactic halo stars. Nucleosynthesis calculations are performed on the basis of thermodynamic histories of mass elements from…