Formation of asteroid pairs by rotational fission

Pravec, P.; Vokrouhlický, D.; Polishook, D.; Scheeres, D. J.; Harris, A. W.; Galád, A.; Vaduvescu, O.; Pozo, F.; Barr, A.; Longa, P.; Vachier, F.; Colas, F.; Pray, D. P.; Pollock, J.; Reichart, D.; Ivarsen, K.; Haislip, J.; Lacluyze, A.; Kušnirák, P.; Henych, T.; Marchis, F.; Macomber, B.; Jacobson, S. A.; Krugly, Yu. N.; Sergeev, A. V.; Leroy, A.
Referencia bibliográfica

Nature, Volume 466, Issue 7310, pp. 1085-1088 (2010).

Fecha de publicación:
8
2010
Revista
Número de autores
26
Número de autores del IAC
0
Número de citas
195
Número de citas referidas
182
Descripción
Pairs of asteroids sharing similar heliocentric orbits, but not bound together, were found recently. Backward integrations of their orbits indicated that they separated gently with low relative velocities, but did not provide additional insight into their formation mechanism. A previously hypothesized rotational fission process may explain their formation-critical predictions are that the mass ratios are less than about 0.2 and, as the mass ratio approaches this upper limit, the spin period of the larger body becomes long. Here we report photometric observations of a sample of asteroid pairs, revealing that the primaries of pairs with mass ratios much less than 0.2 rotate rapidly, near their critical fission frequency. As the mass ratio approaches 0.2, the primary period grows long. This occurs as the total energy of the system approaches zero, requiring the asteroid pair to extract an increasing fraction of energy from the primary's spin in order to escape. We do not find asteroid pairs with mass ratios larger than 0.2. Rotationally fissioned systems beyond this limit have insufficient energy to disrupt. We conclude that asteroid pairs are formed by the rotational fission of a parent asteroid into a proto-binary system, which subsequently disrupts under its own internal system dynamics soon after formation.
Proyectos relacionados
Imagen del Proyecto
Pequeños Cuerpos del Sistema Solar
Este Proyecto estudia las propiedades físicas y composicionales de los llamados pequeños cuerpos del Sistema Solar, que incluyen asteroides, objetos helados y cometas. Entre los grupos de mayor interés destacan los objetos trans-neptunianos (TNOs), incluyendo los objetos más lejanos detectados hasta la fecha (Extreme-TNOs o ETNOs); los cometas, y
Julia de
León Cruz