def v_rad(K, tau, e, long, T0, v0, times):
"""
Calculate the radial (line-of-sight) velocity for a Keplerian orbit
as a function of orbital parameters, COM velocity, and time. The
parameters are:
K = velocity amplitude
tau = period
e = eccentricity
long = longitude of periastron (radians)
T0 = time of periastron crossing
v0 = COM velocity
The times argument can be either a single float (with the velocity
returned as a float) or an array of floats (with the velocity
returned as a corresponding array).
tau, T0 and times should be in the same units (typically days).
K can use a different unit of time (typically m/s).
"""
fkepler.setup_Tp(tau, e, T0)
if type(times)==float:
c, s = fkepler.t2TA(times) # Get cos, sin of true anomaly
else:
c, s = fkepler.vt2TA(times)
return v0 + K*cos(long)*(e+c) + K*sin(long)*s
def v_rad(K, tau, e, long, T0, v0, times):
"""
Calculate the radial (line-of-sight) velocity for a Keplerian orbit
as a function of orbital parameters, COM velocity, and time. The
parameters are:
K = velocity amplitude
tau = period
e = eccentricity
long = longitude of periastron (radians)
T0 = time of periastron crossing
v0 = COM velocity
The times argument can be either a single float (with the velocity
returned as a float) or an array of floats (with the velocity
returned as a corresponding array).
tau, T0 and times should be in the same units (typically days).
K can use a different unit of time (typically m/s).
"""
fkepler.setup_Tp(tau, e, T0)
if type(times) == float:
c, s = fkepler.t2TA(times) # Get cos, sin of true anomaly
else:
c, s = fkepler.vt2TA(times)
return v0 + K * cos(long) * (e + c) + K * sin(long) * s
def Kepler_setup(tau, e, T0, t): global Kepler_c, Kepler_s fkepler.setup(tau, e, T0) Kepler_c, Kepler_s = fkepler.t2TA(t)
def Kepler_setup(tau, e, T0, t):
global Kepler_c, Kepler_s
fkepler.setup(tau, e, T0)
Kepler_c, Kepler_s = fkepler.t2TA(t)