Ceres (dwarf planet)
Ceres is the largest object in the asteroid belt.
It is sometimes assumed that Ceres has been "re"classified as a dwarf planet, and that it is therefore no longer considered an asteroid. For example, a news update at Space.com spoke of "Pallas, the largest asteroid, and Ceres, the dwarf planet formerly classified as an asteroid", whereas an IAU question-and-answer posting states, "Ceres is (or now we can say it was) the largest asteroid", though it then speaks of "other asteroids" crossing Ceres' path and otherwise implies that Ceres is still considered an asteroid. The Minor Planet Center notes that such bodies may have dual designations. The 2006 IAU decision that classified Ceres as a dwarf planet never addressed whether it is or is not an asteroid. Indeed, the IAU has never defined the word 'asteroid' at all, having preferred the term 'minor planet' until 2006, and preferring the terms 'small Solar System body' and 'dwarf planet' after 2006. Lang (2011) comments "the [IAU has] added a new designation to Ceres, classifying it as a dwarf planet. ... By [its] definition, Eris, Haumea, Makemake and Pluto, as well as the largest asteroid, 1 Ceres, are all dwarf planets", and describes it elsewhere as "the dwarf planet–asteroid 1 Ceres". NASA continues to refer to Ceres as an asteroid, as do various academic textbooks.
2018 CY2
is an Apollo asteroid. Apollo's cross the orbit of Earth and are the largest group of near-Earth objects with nearly 10 thousand known members. It orbits the Sun at a distance of 0.92–1.34 AU once every 14 months (438 days; semi-major axis of 1.13 AU). Its orbit has an eccentricity of 0.18 and an inclination of 27° with respect to the ecliptic. It is, however, not a Mars-crossing asteroid, as its aphelion of 1.34 AU is less than the orbit of the Red Planet at 1.666 AU. The body's observation arc begins its first observation at Mount Lemmon in February 2018.