Description
Creates a structure to be used by the other "3b" functions.
This structure contains the necessary information about a specific libration point in a specific system.
The body system can be:
- "S-EM": Sun + barycenter of Earth-Moon
- "E-M": Earth + Moon
- "S-J": Sun + Jupiter
- "-": user-defined
If the body system is "-", the 3 additional arguments (mrat: mass ratio, dist: distance between the 2 main bodies, omega: angular velocity of the line between the 2 main bodies) must be given, otherwise they should be either absent or empty ([]).
The Lagrange point can be either "L1", "L2" or "L3" ("L4" and "L5" are not accepted).
Description of the output structure:
- bodies: (string) System of primaries ("S-EM", "E-M", "S-J" or "-")
- Lpoint: (string) Libration point ("L1", "L2" or "L3")
- D: Distance between the primaries (m)
- OMEGA: Inertial rotation rate of the primaries around their center of mass (rad/s)
- MU: Mass ratio (in ]0, 1]): mass of smallest primary / mass of biggest primary (=mu2/mu1)
- gammal: Adimensional distance (positive) between the libration point and the closest primary: d(P2,L1), d(P2,L2) or d(P1,L3)
- gl: Adimensional abscissa (positive or negative) from the center of mass (G) to the libration point: G-L1 or G-L2 or G-L3
Other quantities for internal use:
- omega_init: Theoretical pulsation of in-plane motion for orbits around the libration point
- pas: internal generation step (adimensional)
- k
- c2
- nu
- invM
- ESCAPEDIR
- ESCAPEDIRNORM
Note:
Conversion between "dimensional" and "adimensional" quantities:
- for lengths: dx = dX / D
- for durations: dt = dT * OMEGA
Where:
- dx and dX: respectively adimensional and dimensional lengths,
- dt and dT: respectively adimensional and dimensional time durations,
- D and OMEGA: as described above.
