# Keplerian Orbits¶

radvel.kepler.kepler(Marr, eccarr)[source]

Solve Kepler’s Equation :param Marr: input Mean anomaly :type Marr: array :param eccarr: eccentricity :type eccarr: array

Returns: eccentric anomaly array
radvel.kepler.rv_drive(t, orbel, use_c_kepler_solver=True)[source]

RV Drive :param t: times of observations :type t: array of floats :param orbel: [per, tp, e, om, K]. Omega is expected to be in radians :type orbel: array of floats :param use_c_kepler_solver: (default: True) If True use the Kepler solver written in C, else use the Python/NumPy version. :type use_c_kepler_solver: bool

Returns: (array of floats): radial velocity model rv
radvel.orbit.timeperi_to_timetrans(tp, per, ecc, omega, secondary=False)[source]

Convert Time of Periastron to Time of Transit

Parameters: tp (float) – time of periastron per (float) – period [days] ecc (float) – eccentricity omega (float) – argument of peri (radians) secondary (bool) – calculate time of secondary eclipse instead time of inferior conjunction (time of transit if system is transiting) float
radvel.orbit.timetrans_to_timeperi(tc, per, ecc, omega)[source]

Convert Time of Transit to Time of Periastron Passage

Parameters: tc (float) – time of transit per (float) – period [days] ecc (float) – eccentricity omega (float) – longitude of periastron (radians) time of periastron passage float
radvel.orbit.true_anomaly(t, tp, per, e)[source]

Calculate the true anomaly for a given time, period, eccentricity.

Parameters: t (array) – array of times in JD tp (float) – time of periastron, same units as t per (float) – orbital period in days e (float) – eccentricity true anomoly at each time array