• In 2006 the International Astronomical Union (IAU) approved a new classification scheme for planets and smaller objects in our Solar System.
Their scheme includes three classes of objects:
(1) "small solar system bodies" (including most asteroids and comets)
(2) “much larger planets” (including Earth, Jupiter, and so on)
(3) “in-between sized dwarf planets".
Figure 15: Pluto
• Pluto, formerly the smallest of the nine "traditional" planets is now considered as a dwarf planet.