A planetary system is a system of stars and various non-stellar astronomical objects: planets and their moons, dwarf planets and their moons, asteroids, meteoroids, comets, and cosmic dust that revolve around a common barycenter, that is, the center of mass.
Our own planetary system, which includes the Earth, together with the Sun forms the Solar System.
The idea of the existence of numerous planetary systems in the world space was first proposed by the Italian astronomer Giordano Bruno (1548-1600). The scientist claimed that the Sun is an ordinary star among the many stars scattered in the Universe, and around each of them revolve in the orbits of the planet. Finally, the idea of other planetary systems received opportunities for development only since the 1920s, when the idea of our Galaxy was formed and new star systems were discovered.
Origin and development of planetary systems.
Planetary systems around stars like the Sun are generally considered to have formed during the same process that led to the formation of stars. Generally accepted modern theories prove that planetary systems are formed from a gas-dust cloud surrounding a star. Under the influence of attractive forces (gravitational and electromagnetic), condensation of individual sections of the cloud occurs. Separate-because it is anisotropic in density, composition, and other physical properties, and where there is more matter, there is condensation.
As of the beginning of 2008, about two and a half hundred planetary systems were discovered. Since it is very difficult to detect an earth-like planet at such distances due to its small size and mass, almost all detected exoplanets are mainly giant planets, which, due to their large size and mass, can only be gas planets. But recently, astronomers discovered a rocky exoplanet near the star Gliese 581. This unqualified success, in turn, indicates the non-uniqueness of our Solar star system and the diversity of the worlds as a whole.
According to a number of cosmogonic theories, in a large part of extrasolar planetary systems, exoplanets are also divided into inner solid-state planets, similar to our terrestrial planets, and outer planets, similar to our giant planets. Other stable combinations of large and small planets at different distances from their star, which are theoretically possible in planetary systems, are also calculated.
Some planetary systems are very different from our own: planetary pulsars were identified by weak fluctuations in the period of pulsation of electromagnetic radiation. Pulsars are formed when supernovae explode, and an ordinary planetary system would not be able to withstand such an explosion — either the planets would evaporate, or the sudden loss of most of the mass of the central star would allow them to leave the star’s area of attraction. One theory is that the star’s existing moons almost entirely evaporated in a supernova explosion, leaving behind planet-like bodies. Or the planets may somehow form in the accretion disk surrounding the pulsar.
The forming planetary systems around the planets were discovered.