Hilda family contribution to the Jupiter Family Comets (JFC)

DI SISTO, R. P.; BRUNINI, A.; DIRANI, L. D.; ORELLANA, R. B.

La Plata

Congreso; Reunión de la Asociación Argentina de Astronomía.; 2003

Facultad de Ciencias Astronómicas y Geofísicas

The distinction between asteroids and comets, is based in their observational qualities rather than in their orbital characteristics. Comets show activity when they reach the interior Solar System. Asteroids from the outer Belt, may have compound of the same volatile material, dust and organic molecules than comets, but they didn´t approach enough to the Sun, to show activity. From the compositional point of view, it is a bit arbitrary or at least difficult to distinguish between asteroids from the external main belt and comets. The firsts may be very similar to comets, or at least be objects of intermediate characteristics. The Hildas asteroids, in 3:2 mean motion with Jupiter, have great quantity of volatiles. The main source of Jupiter Family Comets (JFC) is the transneptunian region, but less than 10 % of them comes from the Troyan swarms. In this article we study the Hilda family as another probable source of JFC. We perform numerical simulations and follow the dynamical evolution of Hildas escaped from the resonance. From the 391 particles that escaped from the resonance, 386 (98.7 %) live at least for 1000 years as JFC. The mean life time in this zone is 1.4 × 106 years. The escape rate of an Hilda asteroid, with diameter D greater than 1 km. Is 1.1 × 10-4, so, there is 65 Hildas with D > 1km. (the typical size of a comet) in the JFC region. Therefore, the contribution of Hilda asteroids to the population of comets is important.