Related papers: High- and Low-$\alpha$ Disk Stars Separate Dynamic…
In this review, I will discuss a few problems which point to the need for improved stellar evolution models of halo stars. Current stellar evolution models do not match the observed $^7$Li abundance patterns, suggesting that the input…
The formation of galaxies can be understood in terms of the assembly patterns of each type of galactic component. To perform this kind of analysis, is necessary to define some criteria to separate those components. Decomposition methods…
We have investigated a group of stars known to have low chromospheric ages, but high kinematical ages. Isochrone, chemical and lithium ages are estimated for them. The majority of stars in this group show lithium abundances much smaller…
Stellar ages are extremely difficult to determine and often subject to large uncertainties, especially for field low-mass stars. We plan to carry out a calibration of the decrease in high-energy emissions of low-mass GKM stars with time,…
The Milky Way has distinct structural stellar components linked to its formation and subsequent evolution, but disentangling them is nontrivial. With the recent availability of high-quality data for a large numbers of stars in the Milky…
We investigate the properties of the double sequences of the Milky Way discs visible in the [$\alpha$/Fe] vs [Fe/H] diagram. In the framework of Galactic formation and evolution, we discuss the complex relationships between age,…
The distribution of Milky Way halo blue horizontal-branch (BHB) stars is examined using action-based extended distribution functions (EDFs) that describe the locations of stars in phase space, metallicity, and age. The parameters of the…
We study the age and metallicity distribution function (MDF) of metal-poor stars in the Milky Way halo as a function of galactocentric radius by combining N-body simulations and semi-analytical methods. We find that the oldest stars…
[ABRIDGED] The purpose of this work is to evaluate how several elements produced by different nucleosynthesis processes behave with stellar age and provide empirical relations to derive stellar ages from chemical abundances. We derive…
Abundances for alpha-elements and Fe in about 150 field subdwarfs and early subgiants with accurate parallaxes and kinematic data are used to discuss the run of abundance ratios in metal-poor stars in the solar neighborhood. Based on…
The high-energy emission from low-mass stars is mediated by the magnetic dynamo. Although the mechanisms by which fully convective stars generate large-scale magnetic fields are not well understood, it is clear that, as for solar-type…
We study the stellar discs and spheroids in eight simulations of galaxy formation within Milky Way-mass haloes in a Lambda Cold Dark Matter cosmology. A first paper in this series concentrated on disc properties. Here, we extend this…
The formation and evolution of low-mass stars within dense halos of dark matter (DM) leads to evolution scenarios quite different from the classical stellar evolution. As a result of our detailed numerical work, we describe these new…
The formation of our Milky Way can be parsed qualitatively into different phases that resulted in its structurally different stellar populations: the halo and the disk components. Revealing a quantitative overall picture of the Galactic…
Our Galaxy is thought to have undergone an active evolutionary history dominated by star formation, the accretion of cold gas, and, in particular, mergers up to 10 gigayear ago. The stellar halo reveals rich fossil evidence of these…
A chromospheric age distribution of 552 late-type dwarfs is transformed into a star formation history by the application of scale height corrections, stellar evolutionary corrections and volume corrections. We show that the disk of our…
Several emerging links between high-redshift observational cosmology and the Galactic fossil evidence found in the kinematics, metallicities and ages of Milky Way stars are discussed. In a flat Cold Dark Matter model with $\Omega\simeq 0.3$…
Resolved surveys of the Milky Way's stellar halo can obtain all 6 phase space coordinates of tens of thousands of individual stars, making it possible to compute their 3-dimensional orbits. Spectral analysis of large numbers of halo orbits…
Differentiating between in-situ and accreted populations in the Milky Way halo is a challenging task. Various kinematic spaces are often used to identify distinct accreted populations from the in-situ Milky Way halo. However, this approach…
[Abridged] We map the stellar age distribution ($\lesssim 1$ Gyr) across a 6kpc$\,\times\,$6kpc area of the Galactic disc to constrain our Galaxy's recent star-formation history. Our modelling draws on the sample of Zari et al. (2021) that…