Exoplanets: nature and models

Exoplanets represent a broad new class of astronomical objects, which became accessible for observations and studies only just before the end of the last century. Owing to continually improving techniques of ground-based observations, and especially observations from space, for a little bit more than two decades thousands of planetary systems of other stars have been discovered, and this process is escalating. Exoplanets are of paramount interest for astrophysical, astrochemical, and dynamical studies. Exoplanetary studies have opened up new horizons to gain insights into fundamental problems of stellar-planetary cosmogony and, in particular, into the question of the origin and evolution of the Solar System. Discoveries of Earth-like planets, especially those orbiting in stellar habitable zones favorable to giving rise to and sustaining life, open new prospects for progress in astrobiology.