MOID (Minimum Orbit Intersection Distance) Random Thoughts

MOID (Minimum Orbit Intersection Distance) Random Thoughts


Earth-crossers such as the Aten and Apollo-class minor planets usually have two close approaches (occasionally one or three in the case of a high-inclination orbit) as they move across the Earth's orbit. Amor-class minor planets, with their nearest point to the Sun exterior to the Earth's orbit, usually have one close approach (occasionally two in the case of a high-inclination orbit). The following chart shows the close-approach details throughout the year of the Amor-class object 433 Eros and the Apollo-class object 1566 Icarus.

The following chart shows, for Apollo-class minor planets, examples of Earth-crossers with only one close approach ((138127) 2000 EE14), two close approaches (69230 Hermes), and three close approaches ((177651) 2004 XM14).

The following chart shows, for Amor-class minor planets, examples of Earth-approachers with only one close approach ((4688) 1980 WF) and two close approaches ((4596) 1981 QB).