Small Solar System body

Euler-Diagram bodies in the Solar System

Small objects in the Solar System ESA25188647

Small Solar System body (SSSB) refers to objects in the Solar System that are neither planets nor dwarf planets, but orbit the Sun. These objects include asteroids, comets, meteoroids, and the distant trans-Neptunian objects. The definition of a Small Solar System Body was formalized by the International Astronomical Union (IAU) in 2006, during their decision to reclassify Pluto as a dwarf planet.

Definition

According to the IAU, a Small Solar System Body is an object in the Solar System that is neither a planet nor a dwarf planet, but is in direct orbit around the Sun and does not have the characteristics of a satellite. The category encompasses a wide range of objects, including most of the asteroid belt objects, comets, and many other irregularly shaped bodies that orbit the Sun.

Types of Small Solar System Bodies

There are several types of objects classified under SSSBs, each with unique characteristics:

Asteroids

Asteroids are rocky objects, primarily found in the asteroid belt between Mars and Jupiter. They range in size from meters to hundreds of kilometers in diameter. Some notable asteroids include Ceres (before it was reclassified as a dwarf planet), Vesta, Pallas, and Hygiea.

Comets

Comets are composed of ice, dust, and rocky material. They are known for their spectacular tails, which become visible as they approach the Sun and the solar radiation causes their ice to sublimate and dust to be released into space. Examples include Halley's Comet and Comet Hale-Bopp.

Meteoroids

Meteoroids are significantly smaller than asteroids, usually ranging in size from small grains to 1 meter in diameter. When a meteoroid enters the Earth's atmosphere and vaporizes, it creates a meteor. If part of it survives the passage through the atmosphere and lands on the Earth, it is called a meteorite.

Trans-Neptunian Objects

Trans-Neptunian Objects (TNOs) are found beyond the orbit of Neptune. This category includes the Kuiper Belt objects, like Pluto and Eris (both of which are also classified as dwarf planets), and the more distant Oort Cloud objects.

Importance

Small Solar System Bodies are of great interest to scientists because they are considered to be the leftover building blocks of the Solar System. Studying them can provide valuable insights into the Solar System's formation and evolution. Missions like NASA's Dawn mission to Vesta and Ceres, and the Rosetta mission to comet 67P/Churyumov–Gerasimenko, have significantly increased our understanding of these primitive bodies.

Challenges in Exploration

Exploring SSSBs poses significant challenges due to their small size, low gravity, and often irregular shapes. Landing on these bodies requires precise navigation and specialized equipment. Despite these challenges, missions to SSSBs are considered crucial for advancing our knowledge of the Solar System.