Date: Thu, 19 Jun 1997 00:18:45 -0400 (EDT)


cc:, matese@usl.deu,,

Subject: matese's comments

Hi Tony,

I have looked over John's comments and find they say much the same as Brian Marsden's comments. I have made a graph of the Tissarand parameter for both comet and asteroid data. If you would like to see them I will send them along. The comet graph suggests to me that comets approaching Mar's orbit are becoming detached from Jupiter. Believe me, I am no expert in the Tisserand concept, but my guess is this is an aging effect. I suspect it takes some time to become detached from the big guy.

Maybe this is the happy answer. When the system was young, the hole was deeper, with nothing inside 0.56 AU, John's magic number. As time passed and comets were perturbed, we began filling the hole, perhaps from 3 AU or so. The hole is an artifect of Kiper belt pass-down and comets deep in the hole are old. Statistically, they spent many orbits getting there and now they are spending a lot of time in a harsh environment which would continue the ageing process at a much more rapid pace. Please read all the maybe's. This is something I suggest we think about, not say we know.