相关论文: Low Mass Stars and the He3 Problem
In the primordial Big Bang nucleosynthesis (BBN), only the lightest nuclides (D, $^3$He, $^4$He, and $^7$Li) were synthesized in appreciable quantities, and these relics provide us a unique window on the early universe. Currently, BBN…
Scaling laws of dust, HI gas and metal mass with stellar mass, specific star formation rate and metallicity are crucial to our understanding of the buildup of galaxies through their enrichment with metals and dust. In this work, we analyse…
By following the evolution of several observed exoplanetary systems we show that by lowering the mass loss rate of single solar-like stars during their two giant branches, these stars will swallow their planets at the tip of their…
As part of a multi-year survey for Wolf-Rayet stars in the Magellanic Clouds, we have discovered a new type of Wolf-Rayet star with both strong emission and absorption. While one might initially classify these stars as WN3+O3V binaries…
We present a comprehensive theoretical investigation of the evolutionary properties of intermediate-mass stars. The evolutionary sequences were computed from the Zero Age Main Sequence up to the central He exhaustion and often up to the…
Context. The origin of the large star-to-star variation of the [Eu/Fe] ratios observed in the extremely metal-poor (at [Fe/H]$\leq-3$) stars of the Galactic halo is still a matter of debate.\\ Aims. In this paper, we explore this problem by…
We study how star formation is regulated in low-mass field dwarf galaxies ($10^5 \leq M_{\star} \leq 10^6 \, \text{M}_{\odot}$), using cosmological high-resolution ($3 \, \text{pc}$) hydrodynamical simulations. Cosmic reionization quenches…
We present a semi-analytic, computationally inexpensive model to identify halos capable of forming a Population III star in cosmological simulations across a wide range of times and environments. This allows for a much more complete and…
We present the first results from our survey of the star-forming complex W3, combining VRI photometry with multiobject spectroscopy to identify and characterize the high-mass stellar population across the region. With 79 new spectral…
A few topics concerning the early chemical evolution of the Milky Way are critically discussed. In particular, it is argued that: 1) Observed abundance patterns of extremely metal poor stars (of Pop. II) do not constrain the mass range of…
[Abridged] We calculate the structural evolution and nucleosynthesis of a grid of models covering the metallicity range: -6.5 < [Fe/H] < -3.0 (plus Z=0), and mass range: 0.85 < M < 3.0 Msun, amounting to 20 stars in total. In this paper,…
The first stars might have been fast rotators. This would have important consequences for their radiative, mechanical and chemical feedback. We discuss the impact of fast initial rotation on the evolution of massive Population III models…
In this last decade, our knowledge of evolutionary and structural properties of stars of different mass and chemical composition is significantly improved. This result has been achieved as a consequence of our improved capability in…
Chemical abundances and abundance ratios measured in galaxies provide precious information about the mechanisms, modes and time scales of the assembly of cosmic structures. Yet, the nucleogenesis and chemical evolution of elements heavier…
We study the chemical abundances of a wide sample of 142 Galactic planetary nebulae (PNe) with good quality observations, for which the abundances have been derived more or less homogeneously, thus allowing a reasonable comparison with…
We build a rigorous statistical framework to provide constraints on the chemical and dust evolution parameters for nearby late-type galaxies with a wide range of gas fractions ($3\%<f_g<94\%$). A Bayesian Monte Carlo Markov Chain framework…
Massive stars play a key role in the evolution of the Universe. Our goal is to compare observed and predicted properties of single Galactic O stars to identify and constrain uncertain physical parameters and processes in stellar evolution…
Within the newly updated version of the Ultra-relativistic quantum molecular dynamics (UrQMD) model in which the Skyrme potential energy-density functional is introduced, the yield ratio between $^3$H and $^3$He clusters emitted from…
New detailed stellar yields of several elemental species are derived for massive stars in a wide range of masses (from 6 to 120 Msol) and metallicities (Z= 0.0004, 0.004, 0.008, 0.02, 0.05). Our calculations are based on the Padova…
The chemical abundance patterns of gas and stars in galaxies are powerful probes of galaxies' star formation histories and the astrophysics of galaxy assembly but are challenging to measure with confidence in distant galaxies. In this…