Related papers: On some Uncertainties in Evolutionary Synthesis Mo…

The stellar initial mass function (IMF) seems to be variable and not universal, as argued in the literature in the last three decades. Several relations among the low-mass end of the IMF slope and other stellar population, photometric or…

The Stellar Initial Mass Function (IMF) characterizes the mass distribution of newly formed stars in various cosmic environments, serving as a fundamental assumption in astrophysical research. Recent findings challenge the prevalent notion…

The uncertainties in the modelling of some important inputs of stellar evolution must be taken into account for a correct interpretation, both of the HR diagrams of individual stars, and of the integrated colors, of stellar clusters. After…

We perform a series of three-dimensional, magnetohydrodynamical (MHD) simulations of star cluster formation including gravity, turbulence, magnetic fields, stellar radiative heating and outflow feedback. We observe that the inclusion of…

We developed a new population synthesis code for groups of massive stars, where we model the emission of different forms of energy and matter from the stars of the association. In particular, the ejection of the two radioactive isotopes…

Binary stellar evolution simulations are computationally expensive. Stellar population synthesis relies on these detailed evolution models at a fundamental level. Producing thousands of such models requires hundreds of CPU hours, but…

Despite valiant efforts over nearly five decades, attempts to determine the IMF over a complete mass range for galactic field stars and in open clusters have proved difficult. Infrared imaging observations of extremely young embedded…

Observed variations in the IMF are reviewed with an emphasis on environmental density. The remote field IMF studied in the LMC by several authors is clearly steeper than most cluster IMFs, which have slopes close to the Salpeter value.…

Despite the fundamental importance of the Milky Way's star formation history (SFH) and initial mass function (IMF), their consistent derivation remains elusive. We aim to simultaneously infer the IMF and the SFH of the Galactic disc…

Recent observations indicate a lower Halpha to FUV ratio in dwarf galaxies than in brighter systems, a trend that could be explained by a truncated and/or steeper IMF in small galaxies. However, at low star formation rates (SFRs), the…

Most simulations of galaxies and massive giant molecular clouds (GMCs) cannot explicitly resolve the formation (or predict the main-sequence masses) of individual stars. So they must use some prescription for the amount of feedback from an…

The initial mass function (IMF) is a key ingredient in many studies of galaxy formation and evolution. Although the IMF is often assumed to be universal, there is continuing evidence that it is not universal. Spectroscopic studies that…

We present a large grid of stellar evolutionary tracks, which are suitable to modelling star clusters and galaxies by means of population synthesis. The tracks are presented for the initial chemical compositions [Z=0.0004, Y=0.23],…

The theory of stellar evolution plays a central role in astrophysics as stellar models are used to infer properties for Galactic and Extragalactic stellar populations as well as exoplanetary systems. However, despite decades of experience,…

In this chapter I give an overall description of the structure and evolution of stars of different masses, and review the main ingredients included in state-of-the-art calculations aiming at reproducing observational features. I give…

The stellar initial mass function (IMF) is an underlying distribution function which determines many important observables, from the number of ionizing photons in a population of some age and metallicity, through the creation rate of…

(shortened) In this contribution an average or Galactic-field IMF is defined, stressing that there is evidence for a change in the power-law index at only two masses: near 0.5 Msun and 0.08 Msun. Using this supposed universal IMF, the…

Gaseous and stellar metallicities in galaxies are nowadays routinely used to constrain the evolutionary processes in galaxies. This requires the knowledge of the average yield per stellar generation, $y_{\text{Z}}$, i.e. the quantity of…

Stars form in clustered environments, but how they form when the available resources are shared is still not well understood. A related question is whether the IMF is in fact universal across galactic environments, a galactic initial mass…

The stellar initial-mass function (IMF) represents a fundamental quantity in astrophysics and cosmology, describing the mass distribution of stars from low to very-high masses. It is intimately linked to a wide variety of topics, including…