[meteorite-list] Minor Planet families

[Rob Matson]

Hi Graham,

> Thanks Rob....so the named groups at the moment just represent similar
> orbiting asteroids which over time have settled into that orbit over
> time after they were nudged from the asteroid belt ...

The "asteroid belt" is a pretty broad term. Between the orbits of Mars
and Jupiter are over a dozen major named families (e.g. Cybele, Eos,
Eunomia, Flora, Hilda, Hungaria, Koronis, Maria, Nysa, Phocaea, Themis,
Main Belt I, Main Belt II, Main Belt IIb, Main Belt IIIa, Main Belt IIIb). It's
not unlike the naming of different meteorite groups: just as all H-chondrites
share common features, each asteroid family has a particular combination
of orbital elements (semi-major axis and inclination are the primary
determinants of a minor planet's family) that distinguish it from its
neighbors.

--Rob