Small Solar System body

Small bodies are one of the International Astronomical Union ( IAU) newly defined in Prague on 24 August 2006 class of celestial bodies.

Definition

Among the small bodies asteroids, comets and meteoroids are summarized orbiting the sun and - unlike dwarf planet - can not form a spherical shape because of their low mass and gravity.

A small body releases gases near the sun, a tail forms, is a comet. Get out of the tail and the body appears in the telescope as a clear-cut structure, it is no longer to be distinguished from an asteroid.

If a small body smaller than a few meters, it is a meteoroid. In Erdferne it is too small for direct observation. But he makes a meteor noticeable if he enters the earth's atmosphere. If he does not completely burn up as shooting star, he reaches the Earth as a meteorite.

Occurrence

Small bodies in the solar system come mainly in three regions before:

• In the asteroid belt, between the inner, terrestrial planets and the outer Jupiter-like planets - as a rock -like asteroids.
• In the Kuiper Belt, which is outside the orbit of Neptune - as very ice-containing asteroids and potential, medium -period comets.
• In the Oort cloud, which forms the outer and spherical zone of the solar system - as a theoretical reservoir for long-period comets.

Formation

Asteroids and comet nuclei are primarily as a primordial material residues that are left over from the formation time of the planetary system, because they have not partnered with other planetesimals to protoplanets or planets. In addition, there is also in some fragments that have emerged from the collision between larger small bodies or from the decay of a comet nucleus to a meteor shower. Such events are also the main cause for the formation of meteoroids. Such small but objects can be knocked out of its surface even at an impact on a larger body such as a planet or a moon.