• DOI:10.1093/mnrasl/slt106
• Corpus ID: 119263066

Asteroids in retrograde resonance with Jupiter and Saturn

@article{Morais2013AsteroidsIR,
  title={Asteroids in retrograde resonance with Jupiter and Saturn},
  author={M H M Morais and F Namouni},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2013},
  volume={436}
}

• M. Morais, F. Namouni
• Published 1 August 2013
• Physics
• Monthly Notices of the Royal Astronomical Society

ABSTRACT We identify a set of asteroids among Centaurs and Damocloids, that orbit contrary to thecommon direction of motion in the Solar System and that enter into resonance with Jupiterand Saturn. Their orbits have inclinations I & 140  and semi-major axes a < 15 AU. Twoobjects are currently in retrograde resonance with Jupiter: 2006 BZ8 in the 2/-5 resonance and2008 SO218 in the 1/-2 resonance. One object, 2009 QY6, is currently in the 2/-3 retrograderesonance with Saturn. These are the first examples of Solar System objects in retrograderesonance. The present resonant configurations last for several thousand years. Brief capturesin retrograde resonance with Saturn are also possible during the 20;000 years integrationtimespan, particularly in the 1/-1 resonance (2006 BZ8) and the 9/-7 resonance (1999 LE31).Key words: celestial mechanics; minor planets, asteroids; comets: general; Oort Cloud;Kuiper belt 1 INTRODUCTIONThe discovery of exoplanets that revolve around their host stars inthe opposite direction to stellar rotation has renewed interest in thedynamics of retrograde motion in N-body gravitational systems.In the Solar System, all major and most minor planets have pro-grade orbits around the Sun except for 50 small bodies known toorbit opposite the common direction (Minor Planet Center as of 1July 2013). Such bodies are thought to originate mainly in the OortCloud comet reservoir (Jewitt 2005). However, numerical simula-tions have recently indicated that retrograde orbits in the inner so-lar system may be produced through the gravitational excitationexerted by the gas giants (Greenstreet et al. 2012). Understandingthe dynamics of retrograde minor bodies may provide clues to themechanisms that reverse major and minor planets’ orbits alike. Inthis Letter, we seek to determine the dynamical states of the mi-nor bodies that reside on retrograde orbits in the vicinity of Jupiterand Saturn. We show that some of the known minor bodies may betrapped temporarily in mean motion resonances with these planetswhere the ratio of their orbital periods are integer fractions.Unlike a number of extrasolar multi-planet systems (˘ 20%),the Solar System’s planets are not in resonance even though thepairs Jupiter-Saturn and Neptune-Uranus are close to the 5/2 and2/1 mean motion resonances respectively. For minor bodies, therole of mean motion resonances is complex. For instance, the 3/1mean motion resonance with Jupiter in the main asteroid belt is aknown source of Near Earth Asteroids (Wisdom 1985; Morbidelliet al. 2002). On the other hand, the Hilda asteroid family residesstably at the 3/2 resonance with Jupiter (Nesvorny & Ferraz-Mello1997). Mean motion resonances also protect objects on Neptune-