Related papers: Stellar Population Models and Individual Element A…
The upper Asymptotic Giant Branch is populated with oxygen rich and carbon rich Long Period Variables. These stars are essential contributors to the near-IR light of intermediate age stellar populations. Individual observed spectra of LPVs…
Our understanding of massive stars remains incomplete. Many high-z galaxies and nearby analogs exhibit strong He II emission, indicating an abundance of photons with energies >54.4 eV that standard single-star population models cannot…
An approach is introduced for incorporating the concept of stellar pollution into stellar evolution models. The approach involves enhancing the metal content of the surface layers of stellar models. In addition, the surface layers of stars…
The discovery of multiple stellar populations in Milky Way globular clusters (GCs) has stimulated various follow-up studies on helium-enhanced stellar populations. Here we present the evolutionary population synthesis models for the…
This paper presents the first results from a model for chemical evolution that can be applied to N-body cosmological simulations and quantitatively compared to measured stellar abundances from large astronomical surveys. This model…
The study of stellar populations is a discipline that is highly dependent on both imaging and spectroscopy. I discuss techniques in different regimes of resolving power: broadband imaging (R~4), intermediate band imaging (R~16, 64),…
We examine contributions of second order physical processes to results of stellar evolution calculations amenable to direct observational testing. In the first paper in the series (Young et al. 2001) we established baseline results using…
Abundance patterns of the elements C, N, and O are sensitive probes of stellar nucleosynthesis processes and, in addition, O abundances are an important input for stellar age determinations. Understanding the nature of the observed…
We derive the abundance of 19 elements in a sample of 64 stars with fundamental parameters very similar to solar, which minimizes the impact of systematic errors in our spectroscopic 1D-LTE differential analysis, using high-resolution…
The evolution of AGB stars is notoriously complex. The confrontation of AGB population models with observed stellar populations is a useful alternative to the detailed study of individual stars in efforts to converge towards a reliable…
We present a new stellar population synthesis model, which predicts SEDs for single-age single-metallicity stellar populations, SSPs, at resolution 1.5A (FWHM) in the spectral region of the near-IR CaII triplet feature. The main ingredient…
I briefly introduce a database of models that describe the evolution of star clusters in several broad-band photometric systems. Models are based on the latest Padova stellar evolutionary tracks - now including the alpha-enhanced case and…
We extend to lower metallicities recent evolutionary computations devoted to Magellanic Clouds stars, presenting and discussing new stellar models with Z=0.0002, 0.0004, 0.0006, 0.001 and suitable assumptions about the original He content.…
The physical properties of galaxies are encoded within their spectral energy distribution and require comparison with models to be extracted. These models must contain a synthetic stellar population and, where infrared data is to be used,…
We have analyzed high-resolution and high signal-to-noise ratio optical spectra of nearby FGK stars with and without detected giant planets in order to homogeneously measure their photospheric parameters, mass, age, and the abundances of…
We have investigated how the relative elemental abundances inferred from the solar upper atmosphere are affected by uncertainties in the dielectronic recombination (DR) rate coefficients used to analyze the spectra. We find that the…
HARPS spectra with signal-to-noise ratios S/N > 600 at 6000 A were analysed with MARCS model atmospheres to obtain 1D LTE abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Sr, and Y for 72 nearby solar-type stars with metallicities in…
We present a sample of synthetic massive stellar populations created using the Starburst99 evolutionary synthesis code and new sets of stellar evolutionary tracks, including one set that adopts a detailed treatment of rotation. Using the…
HARPS spectra with S/N > 600 for 21 solar twin stars are used to determine very precise (sigma ~ 0.01 dex) differential abundances of C, O, Na, Mg, Al, Si, S, Ca, Ti, Cr, Fe, Ni, Zn, and Y in order to see how well [X/Fe] is correlated with…
In this review we address the uncertainties implicit in evolutionary synthesis model computations. After describing the general structure of synthesis codes, we discuss several source of uncertainties that may affect their results. In…