The Centaur population

DI SISTO, ROMINA, P. BRUNINI, A.

Buzios

Simposio; IAU Symposium 129; 2005

IAU

We analyse the  Centaur population as  a group of  objects withperihelion distances (q)  less than 30 AU, formed  by objects enteringthe planetary  zone from the  Scattered Disk (SD) and  objects leavingthe inner solar system. We  perform a numerical integration of 95 realscattered disk  objects (SDOs) extracted from the  Minor Planet Centerdatabase and 905 clones.  We evaluate also, the contribution of Jupiter family comets (JFCs), escaped Hildas and Trojan asteroids. SDOs have in the  Centaur zone a mean  life time of72 My,  although this number fall  with a decrease of  q. After thisincursion, $22 %$  of them enter the JFC zone and  return to the Centaurzone in  their way  to ejection  having there a  mean lifetime  of 1.2My. The mean lifetimes of escaped Hildas in that region is 2.3 My.  Wefound that  the greater contribution  to the Centaur  population comesfrom the SD giving a total of $sim 3 imes 10 ^{8}$ Centaurs with radius $r > 1$ km. A $5 %$ of them  comes from the JFCs and the contribution of external asteroids is negligible. Also we propose a model to the intrinsic distribution of orbital elements of Centaurs, its distance and aparent magnitude distribution.