These codes in fortran calculate the location in semimajor axis, libration centers and the strength of three body mean motion resonances between three massive bodies. The planets are not in mutual two-body resonances, they are called pure three body resonances (not a chain of resonances). The model is given by Gallardo, Coito and Badano (2016, Icarus).

Given 2 planets P1 and P2 with arbitrary orbits the program planetary3br calculates all possible semimajor axes that a third planet P0 can have in order the system to be in a three body resonance. The program calculates also three "strengths" of the resonance, one for each planet. You should take a look at the reference paper otherwise you probably will be lost. Take care, the "strengths" are only indicators of the dynamical relevance of the resonance on each planet. The file planetary3br.zip contains the source code in f77 and the input data file "p3br.inp". You must compile with a fortran compiler to generate the executable. The executable and input data file must be placed in the same directory.

Note: pure three body resonances generally appear at low (e,i) because for large (e,i) values the two body resonances dominate the dynamics.

CODES HERE

Reference: Gallardo, Coito and Badano (2016, Icarus).

Three Body Resonance Locator (try it!)