Hi Bill,

I am sending data for collisional modelling we discussed
in Boulder last week. You can find them here:

http://sirrah.troja.mff.cuni.cz/~mira/mp/tmp/BILL_COLLISIONS/

There are several figures and data files, with self-explaining
names and brief descriptions inside. Namely:

1) size distributions of asteroid populations observed today
   (i.e., something to fit);
2) histograms of dynamical lifetimes (computed for the
   observed objects) - this may be transformed into your
   dynamical removal rate I_dyn (e.g., by averaging);
3) variants of dynamical lifetimes for SMALLER objects,
   which depend on size (due to Yarkovsky-driven removal,
   which is efficient for sizes <~0.1 km).

I suppose, we need NOT to calculate intrinsic collisional
probabilities of J2/1 vs J2/1 objects, because this population
is small anyway and collisions among J2/1 and MB dominate.

The best estimate of family ages so far are:

Hilda family (disruption of a ~200 km PB): >4 Gyr old
Schubart family (~100 km PB): 1.7+-0.7 Gyr

This number/age of families probably also may serve as an
observable quantity, which should be reproducible in your
collisional model.

Well, I do not know if this is exactly what you need
to start the CoDDEM model. In case anything is missing,
let me know and I will try to dig it.

Clear skies, Mira


PS: There are a few caveats, which you probably noticed:

1) I did not estimate the repopulation of the stable resonant
   zone from the neighbourhood main belt, but we can safely
   assume it is probably negligible effect, at least for larger
   bodies (in the observable size range around 10 km).

2) YORP reorientations are not included in the model for J2/1,
   but they ARE included for J3/2 - they are capable to change
   the Yarkovsky drift into a random walk for smallest sizes
   (of the order <~0.1 km) and thus substantially prolong the
   lifetimes of bodies inside resonance.

3) Lifetimes are sometimes calculated upto 1 Gyr only,
   thought they may be longer, of course (mostly 4 Gyr).
   I did not calculate I_dyn for a given size, but I am
   rather sending you complete histograms. (If you wish,
   I can calculate it myself.)