meepmeep.numba3d.zvel_d

meepmeep.numba3d.zvel_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 velocity and its parameter derivatives at an absolute time.

Direct counterpart of zvel_cd: epoch-folds the absolute time time around the expansion point and delegates to zvel_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 velocity.zvel.

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) coefficient matrix produced by solve3d. Only row 2 is read.

dcNDArray

A (7, 3, 5) parameter-derivative tensor produced by solve3d_d. Only the slice dc[:, 2, :] is read.

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:

vzfloat or ndarray

Line-of-sight z velocity in stellar radii per unit time. Positive values indicate motion toward the observer. Shape (N,) for an array time.

dvzNDArray

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