Small Solar System body
A small Solar System body (SSSB) is an object in the Solar System that is neither a planet, a dwarf planet, nor a natural satellite. The term was first defined in 2006 by the International Astronomical Union (IAU) as follows: "All other objects, except satellites, orbiting the Sun shall be referred to collectively as 'Small Solar System Bodies' ".
This encompasses all comets and all minor planets other than those that are dwarf planets. Thus SSSBs are: the comets; the classical asteroids, with the exception of the dwarf planet Ceres; the trojans; and the centaurs and trans-Neptunian objects, with the exception of the dwarf planets Pluto, Haumea, Makemake, and Eris and others that may turn out to be dwarf planets.
Solar phenomena
The Sun is a G-type main-sequence star (G2V) based on spectral class and it is informally designated as a "yellow dwarf" because its visible radiation is most intense in the yellow-green portion of the spectrum. It is actually white, but from the Earth's surface it appears yellow because of atmospheric scattering of blue light. In the spectral class label, "G2" indicates its surface temperature, of approximately 5778 K () and "V" indicates that the Sun, like most stars, is a main-sequence star, and thus generates its energy via fusing hydrogen into helium. In its core, the Sun fuses about 620 million metric tons of hydrogen each second.