Related papers: Lithium abundances in globular clusters
Globular clusters host multiple stellar populations that display star-to-star variation of light elements that are affected by hot hydrogen burning (e.g., He, C, N, O). Several scenarios have been suggested to explain these variations. Most…
Lithium and zirconium abundances (the latter taken as representative for s-process enrichment) are determined for a large sample of massive Galactic O-rich AGB stars, for which high resolution optical spectroscopy has been obtained…
Asymptotic giant branch (AGB) stars can experience proton ingestion events (PIEs), leading to a rich nucleosynthesis. During a PIE, the intermediate neutron capture process (i-process) develops, leading to the production of trans-iron…
The orders of magnitude variation in lithium abundances of evolved stars have long been a puzzle. Diluted signals, ambiguous evolutionary states and unknown masses have made it challenging to both map the expected lithium signals and…
The evolution of star clusters is studied using N-body simulations in which the evolution of single stars and binaries are taken self-consistently into account. Initial conditions are chosen to represent relatively young Galactic open…
Internal chemical abundance spreads are one of fundamental properties of globular clusters (GCs) in the Galaxy. In order to understand the origin of such abundance spreads, we numerically investigate GC formation from massive molecular…
I consider the synthesis of 6Li due to the decay of relic particles, such as gravitinos or moduli, after the epoch of Big Bang Nucleosynthesis. The synthesized 6Li/H ratio may be compared to 6Li/H in metal-poor stars which, in the absence…
This work aims to investigate the behaviour of the lithium abundance in stars with and without detected planets. Our study is based on a sample of 1332 FGK main-sequence stars with measured lithium abundances, for 257 of which planets were…
The fragile light elements lithium, beryllium, and boron are easily destroyed in stellar interiors, and are thus superb probes of physical processes occuring in the outer stellar layers. The light elements are also excellent tracers of the…
Galactic globular cluster stars exhibit abundance patterns which are not shared by their field counterparts. It is clear from recent spectroscopic observations of GC turnoff stars that these abundance anomalies were already present in the…
We briefly describe the cosmological lithium problems followed by a summary of our recent theoretical work on the magnitude of the effects of electron screening, the possible existence of dark matter parallel universes and the use of…
We investigate the suggestion that there are stellar populations in some globular clusters with enhanced helium (Y from 0.28 to 0.40) compared to the primordial value. We assume that a previous generation of massive Asymptotic Giant Branch…
Metal-poor globular clusters (GCs) are both numerous and ancient, which indicates that they may be important contributors to ionizing radiation in the reionization era. Starting from the observed number density and stellar mass function of…
Multiple stellar populations in globular clusters (GCs) are distinct by their different abundances of light elements. The abundance anti-correlations point towards a nucleosynthesis origin due to high-temperature H burning, but it remains…
We review the properties of globular clusters which make them useful for studying the Galactic halo, Galactic chemical evolution, and the early stages of the formation of the Milky Way. We review the evidence that GCs have a chemical…
This work presents a homogeneous determination of lithium abundances in a large sample of giant-planet hosting stars (N=117), and a control sample of disk stars without detected planets (N=145). The lithium abundances were derived using a…
Lithium (Li) is a powerful tracer of stellar mixing, gradually depleted in solar twins by non-standard transport below the convective zone. Here, we identify six new solar twins with exceptionally low Li levels that are not explained by…
Tidal disruption and subsequent accretion of planetesimals by white dwarfs can reveal the elemental abundances of rocky bodies in exoplanetary systems. Those abundances provide information on the composition of the nebula from which the…
Hydrogen-burning is the root cause of the star-to-star abundance variations of light nuclei in Galactic globular clusters (GC). In the present work we constrain the physical conditions that gave rise to the observed abundance patterns of…
We examine the internal structure of solar-like stars in detail between 0.8 and 1.4M Sun and during pre-main sequence phase. Recent opacity computations of OPAL along with a new hydrodynamical mixing process have been considered. We also…