meepmeep.numba3d.zpos_d

meepmeep.numba3d.zpos_d(time: float | ndarray[tuple[Any, ...], dtype[_ScalarT]], tc: float, p: float, c: ndarray[tuple[Any, ...], dtype[_ScalarT]], dc: ndarray[tuple[Any, ...], dtype[_ScalarT]], te: float = 0.0)

Evaluate the line-of-sight z position and its parameter derivatives at an absolute time.

Direct counterpart of zpos_cd: epoch-folds the absolute time time around the expansion point and delegates to zpos_cd.

Accepts a scalar time or a 1-D array of times and dispatches to the appropriate kernel at compile time (inside @njit) or at call time (pure Python), mirroring the value-only position.zpos.

Parameters:

timefloat or ndarray

Absolute observation time(s) in the same units as tc and p.

tcfloat

Transit-centre time (time of inferior conjunction), on the same time axis as time.

pfloat

Orbital period, used for epoch folding.

cNDArray

A (3, 5) Taylor coefficient matrix produced by solve3d.

dcNDArray

A (7, 3, 5) parameter-derivative tensor produced by solve3d_d, with the leading axis ordered as (tc, p, a, i, e, w, lan).

tefloat, optional

Expansion-point offset from the transit centre [days] - the same value that was passed to solve3d_d. Defaults to 0.0, the expansion point at the transit centre.

Returns:

pzfloat or ndarray

Line-of-sight z position in units of stellar radii. Positive values point toward the observer; negative values point away. The sign distinguishes the transit (positive z) and eclipse (negative z) branches of the orbit. Shape (N,) for an array time.

dpzNDArray

Partial derivatives of pz with respect to (tc, p, a, i, e, w, lan). Shape (7,) for a scalar time, (N, 7) for an array time.