Related papers: Spectroscopic and physical parameters of Galactic …
Despite a rich observational background, few spectroscopic studies have dealt with the measurement of the carbon isotopic ratio in giant stars. However, it is a key element in understanding the mixing mechanisms that occur in the interiors…
I will review the role of massive stars in galactic evolution both from the nucleosynthesis and energetics point of view. In particular, I will highlight some important observational facts explained by means of massive stars in galaxies of…
Stellar evolutionary tracks for $0.12 \le M/M_\odot \le 1.0$ have been computed for each of several variations in the abundances of C, N, and O, assuming mass-fraction helium abundances $Y = 0.25$ and $0.29$, and 11 metallicities in the…
Rotational mixing in massive main sequence stars is predicted to monotonically increase their surface nitrogen abundance with time. We use this effect to design a method for constraining the age and the inclination angle of massive main…
(Abridged) We performed a multiwavelength analysis of a sample of starburst galaxies that show the presence of a substantial population of very young massive (WR) stars. Here we present the global analysis of the derived photometric and…
Understanding the evolution of the N/O ratio in the interstellar medium (ISM) of galaxies is essential if we are to complete our picture of the chemical evolution of galaxies at high redshift, since most observational calibrations of O/H…
Modern tools for modeling stellar evolution, such as MESA (Modules for Experiments in Stellar Astrophysics), offer state-of-the-art implementations of stellar theories. However, this parametric approach introduces many free parameters that…
Massive O-type stars lose a significant fraction of their mass through radiation-driven winds, a process that critically shapes their evolution and feedback into the interstellar medium. Accurate predictions of mass-loss rates are essential…
The chemical enrichment of the early Universe is a crucial element in the formation and evolution of galaxies, and Population III (PopIII) stars must play a vital role in this process. In this study, we examine metal enrichment from massive…
The evolution of massive stars is affected by a variety of physical processes including convection, rotation, mass loss and binary interaction. Because these processes modify the internal chemical abundance profiles in multiple ways…
We have investigated the poorly-understood origin of nitrogen in the early Galaxy by determining N abundances in 35 extremely metal-poor halo giants (22 stars have [Fe/H]<-3.0) using the C and O abundances determined in Paper V. Because any…
Key physical ingredients governing the evolution of massive stars are mass losses, convection and mixing in radiative zones. These effects are important both in the frame of single and close binary evolution. The present paper addresses two…
We have obtained HST and ground-based observations of a sample of 20 O-type stars in the LMC and SMC, including six of the hottest massive stars known (subtypes O2-3) in the R136 cluster. In general, these data include (a) the HST UV…
Context. We need to understand the spin evolution of massive stars to compute their internal rotationally induced mixing processes, isolate effects of close binary evolution, and predict the rotation rates of white dwarfs, neutron stars and…
The common - arguably ubiquitous - large-scale variability of optical and UV lines profiles of hot, massive stars is widely interpreted as the direct consequence of structured, variable winds. Many of the variability phenomena are observed…
The abundances of iron and oxygen are homogeneously determined in a sample of 523 nearby (d<150 pc) FGK disk and halo stars with metallicities in the range -1.5<[Fe/H]<0.5. The oxygen abundances were inferred from a restricted non-LTE…
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…
The detection and subsequent characterisation of exoplanets are intimately linked to the characteristics of their host star. Therefore, it is necessary to study the star in detail in order to understand the formation history and…
Massive stars played a key role in the early evolution of the Universe. They formed with the first halos and started the re-ionisation. It is therefore very important to understand their evolution. In this paper, we describe the strong…
High precision photometry and spectroscopy of low-mass stars reveal a variety of properties standard stellar evolution cannot predict. Rotation, an essential ingredient of stellar evolution, is a step towards resolving the discrepancy…