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[8.13] Multinomial Fits to the Observed Main Belt Asteroid Distribution

A. Campo Bagatin (Physikalisches Inst., Univ. Bern (CH)), V.J. Martinez (Obs. Astron., Univ. Valencia (E)), S. Paredes (Dep. Mat. APl. y Estad., Univ. Politec. Cartagena (Murcia) (E))

Dohnanyi's theory predicts that a collisional system such as the asteroid population of the main belt should rapidly relax to a power--law stationary size distribution of the kind N(m)\propto m^-\alpha, with \alpha very close to 11/6, provided all the collisional response parameters are independent on size. The actual asteroid belt distribution at observable sizes, instead, does not exhibit such a simple fractal size distribution.

We investigate the possibility that the actual stationary cumulative distribution of the main asteroid belt at observable sizes --- that substantially deviates from a power--law distribution --- may be instead fairly fitted by multinomial distributions. This multinomial behaviour, which is in contrast with the Dohnany stationary distribution, is related to the release of the hypothesis of self--similarity, mainly due to the increasing effect of self--gravity in collisional processes involving km--size objects in the real asteroid belt population.

The present research has been carried on by A.Campo Bagatin thanks to an European Space Agency postdoctoral fellowship.

The author(s) of this abstract have provided an email address for comments about the abstract: adriano@astronomia.disc.ua.es