Vesta fragments from v6 and 3:1 resonances: Implications for V-type NEAs
and HED meteorites
Authors:
Migliorini, F.; Morbidelli, A.; Zappala, V.; Gladman, B. J.; Bailey, M.
E.; Cellino, A.
Journal:
Meteoritics & Planetary Science, vol. 32, no. 6, pages 903-916
Publication Date:
11/1997
Origin:
METIC
Bibliographic Code:
1997M&PS...32..903M
Abstract
A large body of evidence, including the presence of a dynamical family
associated with 4 Vesta, suggests that this asteroid might
be the ultimate source of both the V-type Near-Earth asteroids (NEAs)
and HED meteorites. Dynamical routes from Vesta to the
inner regions of the Solar System are provided by both the 3:1 mean-motion
resonance with Jupiter and the v6 secular resonance.
For this reason, numerical integrations of the orbits of fictitious
Vesta fragments injected in both of these resonances have been
performed. At the same time, the orbital evolution of the known V-type
NEAs has been investigated. The results indicate that the
dynamical half lifetimes of Vesta fragments injected in both the 3:1
and the v6 resonances are rather short (<2 Myr). The most
important result is that the present location of the 7 known V-type
NEAs is well explained by orbital evolution of ejecta starting
from the v6 secular resonance. However, we now face what we call the
``Vesta paradox''. Roughly speaking, the paradox consists
of the fact that the present V-type NEAs appear to be too dynamically
young to have originated in the event that produced the
family, but they are too big to be plausible second-generation fragments
from the family members. The CRE age distribution of
HED meteorites also raises a puzzle, since we would expect an overabundance
of meteorites with short CRE ages. We propose
different scenarios to explain these paradoxes.