The Janus head of the HD 12661 planetary system

Abstract

In this work we perform a global analysis of the radial velocity curve of the HD 12661 system. Orbital fits that are obtained by the genetic and gradient algorithms of minimization reveal the proximity of the system to the 6:1 mean motion resonance. The orbits are locked in the secular resonance with apsidal axes librating about 180 deg with the full amplitude $\simeq (90,180) deg$. Our solution incorporates the mutual interaction between the companions. The stability analysis with the MEGNO fast indicator shows that the system is located in an extended stable zone of quasi-periodic motions. These results are different from those obtained on the basis of the orbital fit published by Fischer et al. (2003)