Related papers: Element Diffusion and Accretion in Metal Poor Star…
A homogeneous spectroscopic analysis of unevolved and evolved stars in the metal-poor globular cluster NGC 6397 with FLAMES-UVES reveals systematic trends of stellar surface abundances that are likely caused by atomic diffusion. This…
We present a homogeneous photometric and spectroscopic analysis of 18 stars along the evolutionary sequence of the metal-poor globular cluster NGC 6397 ([Fe/H] = -2), from the main-sequence turnoff point to red giants below the bump. The…
When modelling stars with masses larger than 1.2Msun with no observed chemical peculiarity, atomic diffusion is often neglected because, on its own, it causes unrealistic surface abundances compared with those observed. The reality is that…
I review theoretical models of star formation and how they apply across the stellar mass spectrum. Several distinct theories are under active study for massive star formation, especially Turbulent Core Accretion, Competitive Accretion and…
Understanding the interstellar chemistry in low-metallicity environments is crucial to unveil physical and chemical processes in the past Galaxy or those in high-redshift galaxies, where the metallicity was significantly lower compared to…
The formation of a star is a dynamic process fed by the gravitational collapse of a molecular cloud core. Theoretical models and observations suggest that the majority of this infalling material settles into a protoplanetary disk before…
Lithium abundance derived in metal-poor main sequence stars is about three times lower than the value of primordial Li predicted by the standard Big Bang nucleosynthesis when the baryon density is taken from the CMB or the deuterium…
We investigate the formation of carbon-enhanced metal-poor (CEMP) stars via the scenario of mass transfer from a carbon-rich asymptotic giant branch (AGB) primary to a low-mass companion in a binary system. We explore the extent to which…
The metal-poor stars of a galaxy offer insights into that galaxy's early formation processes and accretion history. Here, we investigate whether the metal-poor stars of our Milky Way galaxy exhibit any characteristic trends in…
The solar and extra solar gas giants appear to have diverse internal structure and metallicities. We examine a potential cause for these dispersions in the context of the conventional sequential accretion formation scenario. In principle,…
We want to investigate how planet formation is imprinted on stellar surface composition using up-to-date stellar evolution models. We simulate the evolution of pre-main-sequence stars as a function of the efficiency of heat injection during…
Lithium abundances have been determined in more than 100 metal-poor halo stars both in the field and in clusters. From these data we find trends of Li with both temperature and metallicity and a real dispersion in Li abundances in the Spite…
The entire evolution of the Milky Way, including its mass-assembly and star-formation history, is imprinted onto the chemo-dynamical distribution function of its member stars, f(x, v, [X/H]), in the multi-dimensional phase space spanned by…
Observational advances over the last decade reveal that star formation is associated with the simultaneous presence of gravitationally collapsing gas, bipolar outflow, and an accretion disk. Two theoretical views of star formation suppose…
Our current understanding of the physical processes of star formation is reviewed, with emphasis on processes occurring in molecular clouds like those observed nearby. The dense cores of these clouds are predicted to undergo gravitational…
The recent distance determinations by HIPPARCOS have allowed to locate very precisely a reasonable set of subdwarfs in the HR diagram. A detailed comparison with evolutionary models is now possible and it has been recently claimed that the…
Exo-planets are preferentially found around high metallicity main sequence stars. We aim at investigating whether evolved stars share this property, and what this tells about planet formation. Statistical tools and the basic concepts of…
We find that low-degree low-order g-modes become unstable in metal-poor low-mass stars due to the $\varepsilon$-mechanism of the pp-chain. Since the outer convection zone of these stars is limited only to the very outer layers, the…
Polluted white dwarfs serve as astrophysical mass spectrometers - their photospheric abundances are used to infer the composition of planetary objects that accrete onto them. We show that due to asymmetries in the accretion process, the…
Even today in our Galaxy, stars form from gas cores in a variety of environments, which may affect the properties of resulting star and planetary systems. Here we study the role of pressure, parameterized via ambient clump mass surface…