Figure: Sketch of the dynamical model of a double star system.
The image shows a possible configuration of a circumstellar planetary system around one component of a double star system. Star A at the left is the host star that is orbited by a Giant Planet at some distance, and a companion star (secondary) Star B at some greater distance. Distances from the host star increase towards the right in general. The coloured region denotes the habitable zone; it is of major importance whether or not this region can contain small, rocky planets.
Any object in the habitable zone is modelled as a massless particle, i.e. it feels the gravitational influence of the Giant Planet and Star B, but does not influence them in turn. Such a situation is called the restricted four-body problem.
Figure: First group of input data related to host star and habitable zone.
The important parameters here are the stellar luminosity, effective temperature, and mass of the host star. These parameters determine the location and extent of the habitable zone. Higher luminosity shifts the HZ farther away from the star, while for a lower luminosity it is near to the star.
Four different spectral types are predefined for typical main-sequence stars. Alternatively the user can provide user-defined values for the luminosity and effective temperature. The stellar mass can be set independently in any case.
Figure: Second group of input data related to orbital and physical parameters of giant planet.
The second ingredient is the giant planet exterior to the HZ. The necessary input parameters constitute its mass, distance, and orbital eccentricity. It is implicitly assumed in the dynamical model that the planet moves in the same orbital plane like the two stars, i.e. its orbital inclination is zero.
Figure: Third group of input data related to orbital and physical parameters of secondary star.
The user needs to supply the same parameters for the secondary star like for the planet: mass, distance, and orbital eccentricity. Note that the mass must be in solar masses.
Figure: Fourth group of input data related to computational grid settings.
For the final step the grid parameters must be selected. The two-dimensional grid (x-axis, y-axis) relates to two different parameters among those entered in the steps before. The drop-down lists provide the available options for the grid variables. Additionally, a user may choose the interval for the parameter and how many output points will be generated, i.e. how coarse or fine the grid should be. Note that a finer grid leads to longer computation time.
