On the dynamics of some resonances of Phobos in the future

Universidade Estadual Paulista, IGCE-DEMAC Caixa Postal 178,CEP 13.500-970 Rio Claro (São Paulo), Brasil e-mail: tadashi@ms.rc.unesp.br

Received: 28 April 2004
Accepted: 8 September 2004

Abstract

A probable capture of Phobos into an interesting resonance was presented in our previous work. With a simple model, considering Mars in a Keplerian and circular orbit, it was shown that once captured in the resonance, the inclination of the satellite reaches very high values. Here, the integrations are extended to much longer times and escape situations are analyzed. These escapes are due to the interaction of new additional resonances, which appear as the inclination starts to increase reaching some specific values. Compared to classical capture in mean motion resonances, we see some interesting differences in this problem. We also include the effect of Mars' eccentricity in the process of the capture. The role played by this eccentricity becomes important, particularly when Phobos encounters a double resonance at . Planetary perturbations acting on Mars and variation of its equator are also included. In general, some possible scenarios of the future of Phobos are presented.