The Solar System Around a Binary Star

Sammanfattning: The observations of circumbinary planets have confirmed that these can in fact be stable. While previous studies on circumbinary planets have been done, not many have been made on systems containing multiple circumbinary planets on eccentric orbits. In this thesis, the effects a binary star system of solar mass would have on the Solar System is investigated. Using the program MERCURY, numerous integrations of the Solar System around a tight binary with a separation of less than 1 AU are made and the stability of the orbits of Mercury, Venus, and Earth as a function of the binary separation and the binary mass ratio is investigated. An orbit is considered to be unstable if the planet gets ejected, collides with one of the stars or one of the other planets and the integrations last 10^5 years. The maximum eccentricity of Earth as a function of the binary separation is also investigated. What was found was that the orbit of Mercury was starting to become unstable at a binary separation of approximately $0.33-36a_{initial}$ depending on the mass ratio while Venus and Earth was starting to become unstable at a binary separation of approximately $0.41-0.44a_{initial}$ and $0.44-0.45a_{initial}$ respectively. Furthermore, it was found that there was an interval between $0.38-0.44a_{initial}$ where the maximum eccentricity of Earth were lower compared to binary separations between $0.3-0.37a_{initial}$ possibly due to resonance effects, meaning that Earth has a larger chance to stay within the habitability zone around a binary separation between $0.38-0.44a_{initial}$