API¶
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class
robin.
TransitParams
¶ Object to store the physical parameters of the transit.
Parameters: - t0 (float, optional) – Time of inferior conjunction.
- t_secondary (float, optional) – Time of secondary eclipse center.
- per (float) – Orbital period.
- rp (float) – Planet radius [in stellar radii].
- a (float) – Semi-major axis [in stellar radii].
- inc (float) – Orbital inclination [in degrees].
- ecc (float) – Orbital eccentricity.
- w (float) – Argument of periapse [in degrees]
- u (array_like) – List of limb darkening coefficients.
- limb_dark (str) – Limb darkening model (choice of “nonlinear”, “quadratic”, “exponential”, “logarithmic”, “squareroot”, “linear”, “uniform”, “power2”, or “custom”).
- fp (float, optional) – Planet-to-star flux ratio (for secondary eclipse models).
Note
- Units for the orbital period and ephemeris can be anything as long as they are consistent (e.g. both in days).
- The orbital path is calculated based on t0 for primary transits and t_secondary for secondary eclipses.
Example: >>> import robin >>> params = robin.TransitParams() >>> params.t0 = 0. #time of inferior conjunction >>> params.per = 1. #orbital period >>> params.rp = 0.1 #planet radius (in units of stellar radii) >>> params.a = 15. #semi-major axis (in units of stellar radii) >>> params.inc = 87. #orbital inclination (in degrees) >>> params.ecc = 0. #eccentricity >>> params.w = 90. #longitude of periastron (in degrees) >>> params.u = [0.1, 0.3] #limb darkening coefficients >>> params.limb_dark = "quadratic" #limb darkening model
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class
robin.
TransitModel
(params, t, max_err=1.0, nthreads=1, fac=None, transittype='primary', supersample_factor=1, exp_time=0.0)¶ Class for generating model transit light curves.
Parameters: - params (a TransitParams instance) – A
TransitParams
object containing the physical parameters of the transit - t (ndarray) – Array of times at which to calculate the model.
- max_err (float, optional) – Error tolerance (in parts per million) for the model.
- nthreads (int, optional) – Number of threads to use for parallelization.
- fac (float, optional) – Scale factor for integration step size
- transittype (string, optional) – Type of transit (“primary” or “secondary”)
- supersample_factor (integer, optional) – Number of points subdividing exposure
- exp_time (double, optional) – Exposure time (in same units as t)
Example: >>> m = robin.TransitModel(params, max_err = 0.5, nthreads=4)
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calc_err
(plot=False)¶ Calculate maximum error for transit light curve calculation.
Parameters: plot (bool) – If True
, plots the error in the light curve model as a function of separation of centers.Returns: Truncation error (parts per million) Return type: float
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get_t_conjunction
(params)¶ Return the time of primary transit center (calculated using params.t_secondary).
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get_t_periastron
(params)¶ Return the time of periastron passage (calculated using params.t0).
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get_t_secondary
(params)¶ Return the time of secondary eclipse center (calculated using params.t0).
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get_true_anomaly
()¶ Return the true anomaly at each time
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light_curve
(params)¶ Calculate a model light curve.
Parameters: params (A TransitParams instance) – Transit parameters Returns: Relative flux Return type: ndarray Example: >>> flux = m.light_curve(params)
- params (a TransitParams instance) – A