01/dez/17 – Earth-Size Planet Formation In The ’HabitableZone’ of Binary Stars Systems (Gerson Barbosa, INPE)

It is well known that most of the stellar systems have two or more stars. The binary star systems correspond to a significant part of them. Currently there are 2609 single star systems with planets and 156 binary star systems with planets. From the binary cases only about 20 have planets in P-type orbits, i.e. in circumbinary trajectories. In the present work we are concerned with the possibility of having Earth-like planets in the habitable zone of circumbinary star systems. So, from the known systems with planets in circumbinary orbits we selected those that have all needed data in order to compute their habitable zone. These systems have planets with masses in the range from mini-Neptunes to a few times the Jupiter’s mass. Then, the work was divided into two parts. The first was to study the stability of the habitable zone of each system. The second one was to explore the possibility of formation of an Earth-like planet in the habitable zone. Both parts were made through numerical integrations, taking into account the gravitational effects of the binary star system and the known planets in each case. The stability was studied considering the permanence or not of massless particles in the habitable zone. Therefore, considering the last stage of planetary formation, we explored the evolution of a disk of planetesimals and planetary embrios that under collision with each other accrete and grow. The results are presented in terms of simulations of different disk profiles in order to identify conditions that could possibly form planets with mass similar to the Earth in the habitable zone.