Related papers: The YY Isochrones for alpha-element Enhanced Mixtu…
A common property of globular clusters (GC) is to host multiple populations characterized by peculiar chemical abundances. Recent photometric studies suggest that the He content could vary between the populations of a GC by up to $\Delta$He…
Among the newly discovered features of multiple stellar populations in Globular Clusters, the cluster NGC 1851 harbours a double subgiant branch, that can be explained in terms of two stellar generations, only slightly differing in age, the…
We present the detailed spectroscopic analysis of 72 evolved stars, including the [Fe/H] determination for the whole sample. These metallicities, together with the Teff values and the absolute V magnitude derived from Hipparcos parallaxes,…
Previously [Y/Mg] has been proven to be an age indicator for solar twins. Here, we investigate if this relation also holds for helium-core-burning stars of solar metallicity. High resolution and high signal-to-noise ratio (S/N)…
We investigate the age-chemical abundance structure of the outer Galactic disc at a galactocentric distance of r > 10 kpc as recently revealed by the SDSS/APOGEE survey. Two sequences are present in the [alpha/Fe]-[Fe/H] plane with…
We present models that predict spectra of old- and intermediate-aged stellar populations at 2.51\AA\ (FWHM) with varying [\alpha/Fe] abundance. The models are based on the MILES library and on corrections from theoretical stellar spectra.…
We compute new population synthesis models of Lick absorption line indices with variable alpha/Fe ratios and use them to derive average ages, metallicities, and alpha/Fe element enhancements for a sample of 126 field and cluster early-type…
For nearby K dwarfs, the broadening of the observed Main Sequence at low metallicities is much narrower than expected from isochrones with the standard helium-to-metal enrichment ratio DY/DZ=2. Though the latter value fits well the Main…
An analysis of ages, metallicities, and [alpha/Fe] ratios of globular cluster systems in early-type galaxies is presented, based on Lick index measurements summarized in Puzia et al. (2004, Paper I of this series). In the light of…
We investigated the theoretical possibility of accurately determining the helium-to-metal enrichment ratio $\Delta Y/\Delta Z$ from precise observations of double lined eclipsing binary systems. Using Monte Carlo simulations, we drew…
We built modelled spectra of stellar population at high resolution and with variable alpha-elements enhancements. Analysing spectra of Galactic globular clusters we show that it is possible to derive reliably and efficiently [Mg/Fe] using…
A new set of stellar models in the mass range 1.2 to 9 $M_{\odot}$ is presented. The adopted chemical compositions cover the typical galactic values, namely $0.0001 \le Z \le 0.02$ and $0.23 \le Y \le 0.28$. A comparison among the most…
Seventy-two grids of stellar evolutionary tracks, along with the capability to generate isochrones and luminosity/color functions from them, are presented in this investigation. Sixty of them extend (and encompass) the sets of models…
In the era of large high-resolution spectroscopic surveys, high-quality spectra can contribute to our understanding of the Galactic chemical evolution, providing chemical abundances belonging to the different nucleosynthesis channels, and…
Elemental and isotopic abundances are the fossils of galactic archaeology. The observed [X/Fe]-[Fe/H] relations in the Galactic bulge and disk and the mass-metallicity relation of galaxies are roughly reproduced with chemodynamical…
The ever-expanding depth and quality of photometric and spectroscopic observations of stellar populations increase the need for theoretical models in regions of age-composition parameter space that are largely unexplored at present. Stellar…
Context: Precise chemical abundances coupled with reliable ages are key ingredients to understand the chemical history of our Galaxy. Open Clusters (OCs) are useful for this purpose because they provide ages with good precision. Aims: The…
In this poster line strength indices for new Single Stellar Populations (SSP) based on the recent stellar models with chemical compositions enhanced in the alpha-elements (Salasnich et al. 2000) are presented. The SSP indices have been…
In view of the important contributions of red giants to the integrated light in evolutionary synthesis calculations of old stellar populations in clusters and galaxies, we provide a comparison of theoretical isochrones computed from the…
We combine recently computed models of stellar evolution using a new treatment of rotation with a Bayesian statistical framework to constrain the ages and other properties of early-type stars. We find good agreement for early-type stars and…