Comet characteristics
Most on long elliptical orbits
Short period comets – go to outer solar
system
“Jupiter family” still ~ in plane of ecliptic
“Halley family” are highly inclined to ecliptic
Longer period ones go out thousands of AU
Most of these are highly inclined to ecliptic
Become active only in inner solar system
Made of volatile ices and dust
Sun heats and vaporizes ice, releasing dust
“Dirty snowball” model