SP8 – Binary Stars

The search for Earth-mass planets is currently a venture of great scientific and public interest. It is obvious that the observation for an Exo-Earth will start in the solar neighborhood. A region where more than 60% of the stars are in double or multiple star systems — as was found already in the observational survey by Duquennoy & Mayor in 1991. Therefore, we have to expect an increasing number of planet discoveries in binary star systems in the near future. The probability that an "Exo-Earth" is situated in a double or multiple star system may be quite high. About 60 Jovian planets have already been found in wide and tight binary systems and recently the space mission MOST detected the transit of the terrestrial planet 55 Cnc e in the wide binary star system 55 Cancri (Winn et al. 2011). This makes the study of planets in binary star systems very essential, where questions regarding their formation, long-term stability and atmospheric composition are among major challenges of planetary research.

Considering different types of planetary motion in binary star systems — i.e. circumprimary (or S-type) and circumbinary (or P-type) — we will tackle the following open questions regarding architecture, formation, evolution and habitability of Earth-like planets in such systems:

  • Where is the location of the habitable zone in tight binary star systems?
  • Which of these systems could host habitable planets?
  • Can water-rich terrestrial planets be formed in the HZ of tight binary star systems?
  • What is the probability of impacts of comets/asteroids onto protoplanets in binary star systems?