sailfish.physics.kepler.OrbitalState

class sailfish.physics.kepler.OrbitalState(primary, secondary)[source]

Bases: NamedTuple

Methods

`__init__`()
`count`(value, /)	Return number of occurrences of value.
`gravitational_acceleration`(x, y, ...)	Return the combined gravitational acceleration at a point, with softening.
`gravitational_potential`(x, y, softening_length)	Return the combined gravitational potential at a point, with softening.
`index`(value[, start, stop])	Return first index of value.
`orbital_parameters`(t)	Compute the inverse Kepler two-body problem.
`perturb`(dm1, dm2, dpx1, dpx2, dpy1, dpy2)	Returns a new orbital state vector if this one is perturbed by the given masses and momenta.

Attributes

`angular_momentum`	The total anuglar momentum of the system
`kinetic_energy`	The total kinetic energy of the system
`mass_ratio`	The system mass ratio, secondary / primary
`primary`	Alias for field number 0
`secondary`	Alias for field number 1
`separation`	The orbital separation
`total_energy`	The system total energy
`total_mass`	The sum of the two point masses

property angular_momentum: float: The total anuglar momentum of the system

gravitational_acceleration(x: float, y: float, softening_length: float) → float[source]: Return the combined gravitational acceleration at a point, with softening.

gravitational_potential(x: float, y: float, softening_length: float) → float[source]: Return the combined gravitational potential at a point, with softening.

index(value, start=0, stop=9223372036854775807, /)

Return first index of value.

Raises ValueError if the value is not present.

orbital_parameters(t: float)[source]

Compute the inverse Kepler two-body problem.

This function determines the orbital elements and orientation from the orbital state vector and an absolute time.

perturb(dm1: float, dm2: float, dpx1: float, dpx2: float, dpy1: float, dpy2: float) → OrbitalState[source]

Returns a new orbital state vector if this one is perturbed by the given masses and momenta.

property separation: float

The orbital separation

This will always be the semi-major axis if the eccentricity is zero.