相关论文: The origin of nitrogen: Implications of recent mea…

The apparent absence of stars in the Milky Way halo with -5 ~< [Fe/H] ~< -4 suggests that the gas out of which the halo stars were born experienced a period of low or delayed star formation after the local universe was lit up by the first,…

We examine the impact of discrete numbers of stars in stellar populations on the results of Chemical Evolution Models. We explore the resulting dispersion in the true yields and their possible relation with the dispersion in observational…

The chemical abundances of metal-poor stars provide a great deal of information regarding the individual nucleosynthetic processes that created the observed elements and the overall process of chemical enrichment of the galaxy since the…

We present a comprehensive study of the abundance evolution of the elements from H to U in the Milky Way halo and local disk. We use a consistent chemical evolution model, metallicity dependent isotopic yields from low and intermediate mass…

Halo globular clusters pose four succinct issues that must be solved in any scenario of their formation: single-age, single metallicity stellar populations; a lower limit ([Fe/H] ~ -2.3) to their average metallicity; comprising only 1% of…

Stellar and supernova nucleosynthesis in the first few billion years of the cosmic history have set the scene for early structure formation in the Universe, while little is known about their nature. Making use of stellar physical parameters…

We present an analysis of the chemical compositions in high-redshift galaxies, with a focus on the nitrogen-enhanced galaxies GN-z11 and CEERS-1019. We use stellar models of massive stars with initial masses ranging from 9 to 120 Msol…

We consider the contribution of neutron stars and black holes to the dynamical mass of galactic halos. In particular, we show that if these compact objects were produced by an early generation of stars with initial metallicity less than…

The chemical evolution of galaxies on a cosmological timescale is still a matter of debate despite the increasing number of available data provided by spectroscopic surveys of star-forming galaxies at different redshifts. The fundamental…

We develop a new method to account for the finite lifetimes of stars and trace individual abundances within a semi-analytic model of galaxy formation. At variance with previous methods, based on the storage of the (binned) past star…

Because of their low gravitational energies dwarf galaxies are greatly exposed to energetical influences by the interstellar medium, like e.g.\ stellar radiation, winds or explosions, or by their environment. While the metallicity depletion…

We argue that extreme metal-poor stars show a high dispersion in metallicity, because their abundances are the outcome of very few supernova events. Abundance anomalies should appear because of the discrete range of progenitor masses. There…

We investigate the evolution of the abundance of fluorine in the Milky Way thick and thin discs by means of detailed chemical evolution models compared with recent observational data. The chemical evolution models adopted here have already…

Very old halo stars were previously found to show at least four different abundance 'anomalies', which models of fast rotating massive stars (spinstars) can successfully account for: rise of N/O and C/O, low 12C/13C and a primary-like…

This paper presents theoretical star formation and chemical enrichment histories for the stellar halo of the Milky Way based on new chemodynamical modeling. The goal of this study is to assess the extent to which metal-poor stars in the…

Massive stars rotate faster, on average, than lower mass stars. Stellar rotation triggers hydrodynamical instabilities which transport angular momentum and chemical species from the core to the surface. Models of high-mass stars that…

We interpret the peculiar super-solar nitrogen abundance recently reported by the James Webb Space Telescope observations for GN-z11 ($z=10.6$) using our state-of-the-art chemical evolution models. The observed CNO ratios can be…

The abundances of iron and oxygen are homogeneously determined in a sample of 523 nearby (d<150 pc) FGK disk and halo stars with metallicities in the range -1.5<[Fe/H]<0.5. The oxygen abundances were inferred from a restricted non-LTE…

We present chemical abundances of 57 metal-poor stars that are likely constituents of the outer stellar halo in the Milky Way. Almost all of the sample stars have an orbit reaching a maximum vertical distance (Z_max) of >5 kpc above and…

Small stellar systems like dwarf galaxies are suggested to be the main building blocks of our Galaxy by numerical simulations in Lambda CDM models. The existence of star streams like Sagittarius tidal stream indicates that dwarf galaxies…