Related papers: Mass loss law for red giant stars in simple popula…
Context: Mass loss from red giants in old globular clusters affects the horizontal branch (HB) morphology and post-HB stellar evolution including the production of ultraviolet-bright stars, dredge up of nucleosynthesis products and…
[Abridged] In recent years the view of Galactic globular clusters as simple stellar populations has changed dramatically, as it is now thought that basically all GCs host multiple stellar populations, each with its own chemical abundance…
We examine the biases inherent to chemical abundance distributions when targets are selected from the red giant branch (RGB), using simulated giant branches created from isochrones. We find that even when stars are chosen from the entire…
This paper explores if, and to what an extent, the stellar populations of early type galaxies can be traced through the colour distribution of their globular cluster systems. The analysis, based on a galaxy sample from the Virgo ACS data,…
Mass is constantly being recycled in the universe. One of the most powerful recycling paths is via stellar mass-loss. All stars exhibit mass loss with rates ranging from ~10(-14) to 10(-4) M(sun) yr-1, depending on spectral type, luminosity…
We examine various implications from a dynamical and chemical model of globular clusters (GCs), which successfully reproduces the observed abundance patterns and the multiple populations of stars in these systems assuming chemical…
Context. The asymptotic giant branch (AGB) phase marks the end of the evolution for low- and intermediate-mass stars, which are fundamental contributors to the mass return to the interstellar medium and to the chemical evolution of…
The mass-loss rates of red supergiant stars (RSGs) are poorly constrained by direct measurements, and yet the subsequent evolution of these stars depends critically on how much mass is lost during the RSG phase. In 2012 the Geneva…
We present a new asteroseismic analysis of the stars in the Globular Cluster (GC) M4 based on the data collected by the K2 mission. We report the detection of solar-like oscillation in 37 stars, 32 red giant branch (RGB) and 6 red…
We exploit multi-band Hubble Space Telescope photometry to investigate multiple populations (MPs) along the red horizontal branches (HBs) and red clumps of fourteen metal-rich Globular Clusters (GCs), including twelve Milky Way GCs and the…
Two generations of stars, G1 and G2, typically populate Galactic globular clusters (GCs). The origin of G2 stars is unclear. We uncover two empirical dependencies between GC characteristics, which can be explained by the formation of G2…
We investigate the relationship between the mass of a globular cluster core and the sizes of its various stellar populations in a sample of 56 globular clusters. The number of core red giant branch stars is found to scale sub-linearly with…
The determination of stellar metallicity and its gradient in external galaxies is a difficult task, but crucial for the understanding of galaxy formation and evolution. The color of the Red Giant Branch (RGB) can be used to determine…
Nearly all globular clusters (GCs) studied to date show evidence for multiple stellar populations, in stark contrast to the conventional view that GCs are a mono-metallic, coeval population of stars. Building on earlier work, we propose a…
Most metal-rich AGB/RGB stars present strong Li underabundances, since this element is easily destroyed in the high temperatures of the stellar interiors. In spite of this fact, several of these stars are Li-rich, having Li abundances given…
We aim to perform a theoretical evaluation of the impact of the mass loss indetermination on asteroseismic grid based estimates of masses, radii, and ages of stars in the red giant branch phase (RGB). We adopted the SCEPtER pipeline on a…
Disentangling distinct stellar populations along the red-giant branches (RGBs) of Globular Clusters (GCs) is possible by using the pseudo two-color diagram dubbed chromosome map (ChM). One of the most intriguing findings is that the…
The observed mass-to-light (M/L) ratios of globular clusters (GCs) are on average ~20% lower than expected from Simple Stellar Population (SSP) models, which only account for the effects of stellar evolution. We study the M/L ratio…
Most Globular Clusters so far examined host (at least) two stellar populations. This feature requires a two--step process, in which the nuclearly processed matter from a first generation (FG) of stars gives birth to a second generation (SG)…
Stars in globular clusters (GCs) exhibit a peculiar chemical pattern with strong abundance variations in light elements along with a constant abundance in heavy elements. These abundance anomalies can be explained by a primordial pollution…