Low-frequency Slivan states in the outer main belt?

Institute of Astronomy, Charles University, V Holešovičkách 2, 180 00 Prague 8, Czech Republic
e-mail: vrastil@sirrah.troja.mff.cuni.cz; vokrouhl@cesnet.cz

Received: 14 October 2015
Accepted: 5 December 2015

Abstract

Context. Spin states of several main belt asteroids have been recently found to reside in what is called the Slivan state, namely a secular spin-orbit resonance with the s₆ mode of their orbital precession in space.

Aims. We examine a possibility of the Slivan states of asteroids with other than orbital s₆ precession frequency.

Methods. The asteroids’ orbital and spin states are numerically propagated using well-tested computer codes. We select parameter space favorable for the Slivan-state capture with the s₇ frequency mode of the orbital precession. The stability of these states is numerically verified.

Results. We find that asteroid (184) Dejopeja has a spin state captured in (or very nearly) the Slivan state with the s₇ orbital frequency. In general, such a situation may favorably occur for low-inclination orbits in the outermost part of the main asteroid belt. We expect these states to be common among the Themis family members.