Typically, planets did not form at the distance from their central stars where we observe them today. In fact, during their early evolution, planets migrate from their initial orbit until the system reaches its final configuration. Planetary migration can be induced by several processes: the interaction between the newborn planets and the protoplanetary disk where they formed, the gravitational interaction
Nature sets a lower limit on stellar masses: objects less massive than 0.07-0.08 solar masses are incapable of initiating the thermonuclear reactions that power more massive stars. Below this threshold lies the realm of brown dwarfs, objects whose mass is too small to qualify as stars, yet too large to be categorized as planets. The mechanism responsible for the
Flares are transient and energetic phenomena that occur in most stars and can be observed with high spatial and temporal resolution in the Sun. These phenomena are triggered by a sudden release of energy previously stored in the star’s magnetic field, which, after a sequence of events, leads to extreme heating of the stellar plasma. The heated plasma then rapidly
Almost all stars in the Universe produce their own magnetic field with a process called stellar dynamo, whose basic ingredients are stellar rotation and convection. In general, magnetic fields are produced and are affected by charged particles, which is what stellar plasma is made of. In stars the magnetic field and plasma thus interact, producing a class of transient phenomena
Stars are variable sources over timescales which depend on the phenomena triggering this variability. These phenomena are typically produced by the interaction between the stellar magnetic field and its plasma. Typical examples, observed and studied in great details in the Sun, are: flares (sudden release of a large amount of energy by the magnetic field which heats the gas in
The NASA satellite Transiting Exoplanet Survey Satellite (TESS) it’s one of the most effective telescopes to search for exoplanets. TESS is designed to find exoplanets with the transits method, e.g. by observing the periodic occultations of stars by their planets during their orbits. To date, about 27% of the exoplanets discovered with TESS belong to the class of the sub-neptunians. These planets have a
The exoplanetary systems discovered so far (3212 systems with a total of 4331 exoplanets, as reported by https://exoplanets.nasa.gov/ on January 21st 2021) show a great variety of systems architecture, with some configurations which are completely different than that of our Solar System. This variety of architectures is a challenge for studies of the planetary formation process and all mechanisms that contribute in
The final architecture of a planetary system is the result of a complex interplay between several processes, such as the dispersion of the protoplanetary disk from which the planetary system formed, and the gravitational interaction between the newborn planets. Besides, these processes can be affected by the environment and by their central star. One of the most important process dictating
