Description
IMF, multiplicity, stellar cluster evolution, dark matter in stars
Stars are complex three-dimensional (3D) objects involving many physical processes: convection, rotation, magnetic fields. In this talk, I will review the efforts to constrain the physical ingredients of 1D stellar evolution models of the first stars using multi-D (magneto-)hydrodynamic simulations.
Thanks to space missions, measurements of solar-like oscillations are now available for a large sample of stars. This has led to the precise characterization of the global and internal properties of these stars, and in particular of their internal rotation. In this talk, we will first discuss how these asteroseismic measurements can help us progress in the modelling of angular momentum...
We derive stellar masses and precise chemical abundances for 26 halo red giants, among which 5 and 17 turned out to be [Fe/H]<-2 and <-1, respectively, by combining high-resolution spectroscopy and asteroseismology. We selected the 26 stars in the Kepler field based on radial velocity and metallicity estimated from spectroscopic surveys and confirmed that they show halo-like kinematics using...
The Sun holds a special place in stellar astrophysics, we use it as reference for the determination of the chemical abundances of all stars in the Milky Way. Since 1962, the field of helioseismology has provided unprecedented ways of testing the internal structure of solar models. Soon after the discovery of neutrino-oscillation and the end of the solar neutrino problem, the revision of the...
Binary stellar systems are unique astrophysical laboratories for the study of black holes (BHs). Accretion of matter from a binary companion gives rise to X-ray emission, bringing them to the X-ray binary phase and making them visible on Gpc scales, while the recent gravitational wave observations enabled us to witness the last few seconds of the lives of coalescing binary BHs. X-ray binaries...
Supermassive stars (SMSs) are candidates for being the progenitors of the most massive quasars discovered recently at high redshift. The viability of this formation channel (direct collapse) depends on the properties of the progenitor, whose evolution is dominated by rapid accretion. I will present the most recent models of SMSs, that include accretion and rotation, and discuss their...
I will review (some of) the latest developments in chemo-dynamical numerical simulations of galaxies, particularly focusing on the early formation stages.
To understand the formation and evolution of Milky Way galaxy, Galactic Chemical Evolution (GCE) simulations are performed using N-body Monte Carlo technique. Our GCE models predict the elemental abundance gradients of C, N, O, Mg, Si, Ca, Ti, Fe, and Zn using the revised solar abundance of value 0.0143. The galaxy is radially divided into eight annular rings of 2 kpc width each at a distance...
We present observations and theoretical models regarding the formation of the Galactic bulge. Our main interest concerns the blue horizontal branch and moderately metal-poor globular clusters, that might be among the oldest objects in the Galaxy. We also present abundances, in particular of heavy elements, that could provide evidence for early s-process nucleosynthesis in early rotating massive stars.
We have recently investigated the origin of chemical signatures observed in the oldest star of our Galaxy by means of a stochastic chemical evolution model. The elements we have studied are carbon, nitrogen and oxygen and furthermore neutron-capture elements. We have found that rotating massive stars are a promising way to explain several signatures observed in these fossil stars.
Analysing...
