Bibcode
Tancredi, G.; Motta, V.; Froeschlé, C.
Referencia bibliográfica
Astronomy and Astrophysics, v.356, p.339-346 (2000)
Fecha de publicación:
4
2000
Revista
Número de citas
7
Número de citas referidas
7
Descripción
By comparison of different parameters associated with a chaotic
evolution, we discuss the relation between several populations of inner
Solar System bodies. Tancredi (1998) found that the observed sample of
Jupiter family comets (JFCs) and near-Earth asteroids (NEAs) have
Lyapunov times (the inverse of Lyapunov characteristic exponents)
grouped in the range between 50 and 150 yr, however the dynamical
evolution is strikingly different. By numerical integrations of the
gravitational equations we compute a finite estimate of the Lyapunov
characteristic exponent, the so-called Lyapunov characteristic
indicators (LCIs). The LCI is found by adding short time contributions,
the so-called `local Lyapunov characteristic indicators'
(cite{froeschle}). The distribution of the local Lyapunov
characteristic indicators (DLI) is invariant within a chaotic region and
gives us more complete information about the chaotic behaviour. To
compare the DLIs of different objects we compute the first four moments
of the distributions. Though JFCs and NEAs have similar LCIs, the
analysis of the four moments makes possible the distinction between the
two populations, since they occupy separate regions in the moment
phase-space. We discuss the origin of the Jupiter family as the result
of the splitting of a giant comet several thousand years ago. We
simulate that event and integrate the dynamical evolution of the
fragments. By comparing the DLIs of the fragments with the present JF
objects, we observe a much more compact distribution of moments in the
simulations than in the real population. The splitting hypothesis is not
a plausible explanation for the origin of JFCs. Neither is there
evidence for a few-body splitting event generating ~ 10 comets.
Nevertheless, the comparison of DLIs proves to be a useful tool for
discussing some splitting events already suggested among observed JFCs.