The catalogue also shows the 12 real systems that were investigated. In the upper and lower graphs (Fig. 4), it is clear that the unstable regions also correspond to secondary resonances (see Érdi et al. 2007b), at the mass ratios μ = 0.004 (caused by A 5:1) μ = 0.006 (A 4:1), μ = 0.009 (A 3:1), μ = 0.014 (B 3:1), μ = 0.015 (A 2:1), μ = 0.022, and μ = 0.01 (B 2:1) between the libration periods of the Trojan planet. These are the resonances that perturb the orbits of the Trojan planets and change the size (visible as gaps in this Figure) of the stable regions.
In this article we concentrated on possible terrestrial Trojan planets that may stay around the equilateral equilibrium points of a system consisting of a host star and a gas giant. We investigated 12 different EPSs in detail and found that stable regions around these points would allow planets to move there and to stay there for long times on orbits of low eccentricity. We can conclude that 7 of the 12 real systems have good initial conditions for habitability; but in the context of the spectral type of the central star, we find that HD93083, HD28185, and HD17051 have even better conditions for habitability of a possible Trojan planet. In addition, we compiled a new catalogue of such stable regions for different mass ratios of the primary bodies (host star and GG) and different eccentricities of their orbits. We also determined the stable area by using the results of integrations for 10^7 periods.
The results (more details see also Schwarz et al. 2007c) can be used for any EPSs found in the future to tell the probability of having a large enough region around the L4 or L5 points to host terrestrial planets. This new catalogue is especially useful for single planetary systems when estimating the size of the stable regions around the equilateral Lagrangian points.We emphasise that this catalogue is a useful tool, because the stable regions can be derived be a simple scaling using our results (see Sect. 4). It may also be important for future detection of real Trojan planets in EPS via sophisticated observation techniques from the ground or space.