2006ApJ...644..543H

It has been suggested that the long-lived residual radial velocity variations observed in the precision radial velocity measurements of the primary of γ Cephei (HR 8974, HD 222404, HIP 116727) are likely due to a Jupiter-like planet orbiting this star. In this paper, the dynamics of this planet is studied, and the possibility of the existence of a terrestrial planet around its central star is discussed. Simulations, which have been carried out for different values of the eccentricity and semimajor axis of the binary, as well as the orbital inclination of its Jupiter-like planet, expand on previous studies of this system and indicate that, for the values of the binary eccentricity smaller than 0.5, and for all values of the orbital inclination of the Jupiter-like planet ranging from 0° to 40°, the orbit of this planet is stable. For larger values of the binary eccentricity, the system becomes gradually unstable. Integrations also indicate that, within this range of orbital parameters, a terrestrial planet, such as an Earth-like object, can have a long-term stable orbit only at distances of 0.3-0.8 AU from the primary star. The habitable zone of the primary, at a range of approximately 3.05-3.7 AU, is, however, unstable.