Related papers: An inhomogeneous model for the Galactic halo: a po…
We present the chemical abundances of Fe, alpha- and neutron-capture elements in 12 metal-poor Small Magellanic Cloud (SMC) giant stars, observed with the high-resolution spectrographs UVES/VLT and MIKE/Magellan. These stars have [Fe/H]…
Thanks to the long-term collaborations between nuclear and astrophysics, we have good understanding on the origin of elements in the universe, except for the elements around Ti and some neutron-capture elements. From the comparison between…
The chemical abundances of metal-poor stars in globular clusters provide important constraints on their evolutionary scenarios. Using both main r-process and weak r-process patterns, we fit the abundances of s-poor stars in the globular…
The processes that disperse the products of massive stars from their birth sites play a fundamental role in determining the observed abundances. I discuss parameterizations for element dispersal and their roles in chemical evolution, with…
We compare the metallicity distribution of Galactic Halo stars with 3D realizations of hierarchical galaxy formation. Outflows from dwarf galaxies enrich the intergalactic medium inhomogeneously, at a rate depending on the local galaxy…
We measure abundances of 12 elements (Na, Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni) in a sample of 86 metal-poor ($-2 \lesssim \text{[Fe/H]} \lesssim -1$) subgiant stars in the solar neighborhood. Abundances are derived from…
Recently Lian et al. (2023), thanks to Gaia-ESO data, studied the chemical evolution of neutron-capture elements in the regime [Fe/H]>-1. We aim here to complement this study down to [Fe/H]=-3, and focus on Ba, Y, Sr, and abundance ratios…
The rapid neutron capture process (r process) is believed to be responsible for about half of the production of the elements heavier than iron and contributes to abundances of some lighter nuclides as well. A universal pattern of r-process…
Rapid neutron capture process (r-process) elements have been detected in a large fraction of metal-poor halo stars, with abundances relative to iron (Fe) that vary by over two orders of magnitude. This scatter is reduced to less than a…
We present a cosmologically motivated model for the hierachical formation of the stellar halo which includes a semi-analytic treatment of galactic chemical enrichment coupled to numerical simulations that track the orbital evolution and…
The abundances of elements in stars are a critical clue to their origins. Observed star-to-star variations in logarithmic abundance within an open cluster are typically only $\sim 0.01-0.05$ over many elements, significantly smaller than…
A rudimentary, one-zone, closed-box model for inhomogeneous chemical evolution is offered as an alternative reference than the Simple model in the limit of no mixing. The metallicity distribution functions (MDFs) of Galactic halo and bulge…
In search for a synthetic understanding, a scenario for the evolution of the star formation rate and the chemical abundances in galaxies is proposed, combining gas infall from galactic halos, outflow of gas by supernova explosions, and an…
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…
The member stars in globular cluster M15 show a substantial spread in the abundances of r-process elements. We argue that a rare and prolific r-process event enriched the natal cloud of M15 in an inhomogeneous manner. To critically examine…
Understanding the evolution of the N/O ratio in the interstellar medium (ISM) of galaxies is essential if we are to complete our picture of the chemical evolution of galaxies at high redshift, since most observational calibrations of O/H…
We study the evolution of Eu and Ba abundances in local group dwarf spheroidal and ultra faint dwarf galaxies by means of detailed chemical evolution models and compare our results with new sets of homogeneous abundances. The adopted models…
Studies of nucleosynthesis in neutrino-driven winds from nascent neutron stars show that the elements from Sr through Ag with mass numbers A~88-110 are produced by charged-particle reactions (CPR) during the alpha-process in the winds.…
To better characterize the abundance patterns produced by the r-process, we have derived new abundances or upper limits for the heavy elements zinc (Zn), yttrium (Y), lanthanum (La), europium (Eu), and lead (Pb). Our sample of 161…
The imprints of stellar nucleosynthesis and chemical evolution of the galaxy can be seen in different stellar populations, with older generation stars showing higher $\alpha$-element abundances while the later generations becoming enriched…