Shown below is the distribution of asteroids and comets in semimajor axis, eccentricity space contained in the inner solar system. Note that the range of semimajor axis includes Earth at 1 AU, Mars at 1.52 AU, and Jupiter at 5.2 AU. Asteroids are shown in orange (small dots) while comets are shown in cyan (larger dots).

The dotted line represents the Jupiter Tisserand invariant (T) evaluated at T=3 and zero inclination (i). This boundary very roughly separates small-bodies which are dynamically bound to Jupiter from those which are not. The region above this curve represents objects with T<3 (i.e. bound to Jupiter). Notice that most comets as well as the Trojan asteroids appear in that upper region (T<3, bound to Jupiter) while nearly all asteroids are contained in the region below the curve where T>3 (i.e. not bound to Jupiter).

This graph was created in June 2007 using all asteroids and comets with "well-determined" orbits (specifically, numbered asteroids and comets).

A Postscript version of this plot is also available.