Terrestrial planet formation in binary star systems

Abstract

Most stars reside in binary/multiple star systems; however, virtually all previous models of planetary growth have assumed an isolated single star. Numerical simulations of the collapse of molecular cloud cores to form binary stars suggest that disks will form within binary star systems. Observations indirectly suggest the presence of disk material around one or both components within young binary star systems. If planets form at the right places within such disks, they can remain in stable orbits for very long times. We are simulating the late stages of growth of terrestrial planets within binary star systems, using two new symplectic integrators that we have developed for this purpose. We show that the late stages of terrestrial planet formation can indeed take place in a wide variety of binary systems, and we have begun to delineate the range of parameter space for which this statement is true. This paper presents results of our initial simulations of planetary growth around each star in the α Centauri AB system and in other 'wide' binary systems, as well as around both stars in close binary systems.