•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