An intriguing result, obtained thanks to the observational campaign carried out with NASA’s Kepler satellite, is that the most common transiting exoplanets are small planets with a radius smaller than 4 Earth radii and a short orbital period (less than 100 days). In particular, the most frequent planets belong to the sub-Neptune and super-Earth classes, two categories absent in the
In the Universe, various environments are characterized by shocks capable of converting the kinetic energy of gas and particle flows into heat, turbulence, magnetic energy, and, ultimately, accelerating particles to relativistic energies, producing cosmic rays. The sizes of these systems can vary by many orders of magnitude, ranging from the typical dimensions of the interplanetary environment to the enormous galaxy
With over 2.600 exoplanets discovered, NASA’s Kepler satellite holds the record for the mission with the highest number of exoplanets found. The Kepler mission continued with the Kepler/K2 extension, redefined after technical failures prevented the telescope from maintaining its pointing. Among the many discoveries made possible by Kepler/K2 is evidence that one of the most common types of planets in
In stars, a continuous tug-of-war unfolds between stellar plasma and the magnetic field. At stake is control over the local dynamics: the winner sets the rules that govern the local stellar properties. For instance, the photosphere of stars is generally quite homogeneous, except for granulation. However, in certain regions of the photosphere, the magnetic field can concentrate, intensify, and produce
Supernova remnants serve as unique laboratories to understand the complex processes occurring during a supernova explosion and to investigate the internal structure of massive stars just before their explosive demise. Additionally, the study of these remnants is driven by their crucial role in accelerating cosmic rays, which are particles with extremely high energies. In 1949, Enrico Fermi laid the groundwork for
Young exoplanets, that is, those orbiting stars no older than a few hundred million years, are of significant scientific interest for studying planetary formation and the processes influencing the early evolution of planets. However, the intense magnetic activity of young stars generates signals that can obscure or mimic those linked to the presence of planets, making their detection and characterization
The star-forming regions can differ significantly from one another, particularly in terms of the population of massive stars (with masses exceeding about 10 solar masses) and stellar density (defined as the number of stars per unit volume). These aspects can vary drastically from one region to another. Such differences are extremely important, as massive stars create environments dominated by high-energy
The properties and morphology of supernova remnants result from complex physical processes in the progenitor star, both in the stages preceding the explosion and during the event itself. This involves the rapid collapse of the core, occurring in seconds, up to the shock wave reaching the star’s surface. Additionally, the supernova’s evolution is shaped by interactions between the star’s expelled
The characterization of exoplanetary atmospheres is one of the most active research fields in modern astrophysics, made possible by the development of dedicated instruments and techniques. The basic idea of this research is quite simple: obtaining spectroscopic observations of stars with planets during the transit of the planet in front of its star, which is the moment when part of
Most stars behave like enormous dynamos, producing intense magnetic fields within them. These magnetic fields then interact with the plasma that constitutes the star’s interior and atmosphere, in a constant tug of war where the prevailing force dominates the dynamics. In the outer region of stars, from the photosphere to the corona, the pressure exerted by the gas is less
