Implemented transit models#
PyTransit implements a set of transit models that all share a common interface that is described in more detail in Transit Models.
Road Runner model#
RoadRunner (pytransit.RoadRunnerModel
) is a fast and flexible transit model presented in Parviainen (accepted to MNRAS 2020).
I’ll write a proper documentation soon, but these example notebooks should help you up to speed until then
Uniform model#
The uniform model (pytransit.UniformModel
and pytransit.UniformModelCL
) reproduces an exoplanet transit over a uniform disc.
This model is useful when modelling secondary eclipses, or when the effects from the stellar limb
darkening can be ignored.
Quadratic model#
The quadratic transit model (pytransit.QuadraticModel
and pytransit.QuadraticModelCL
) reproduces an exoplanet transit over a
stellar disk with the limb darkening modelled by a quadratic limb darkening model, as presented
in Mandel & Agol (ApJ 580, 2001).
Oblate star model#
TBD
Power-2 model#
Power-2 model (pytransit.QPower2Model
and pytransit.QPower2ModelCL
) implements the transit model with a power-2 law
limb darkening profile presented by
Maxted & Gill (A&A 622, A33 2019).
The model is fast to evaluate and aims to model the limb darkening accurately for cool stars.
Notes:
Accurate limb darkening model for cool stars.
Fast to evaluate.
General model#
The general model (pytransit.GeneralModel
) implements the flexible transit model presented by
Giménez (A&A 450, 2006). The stellar limb
darkening follows a “general” limb darkening model, and the accuracy of limb darkening can be increased as needed.
The model is calculated using a polynomial series and both the number of polynomials npoly and the number of limb darkening coefficients nldc can be set in the initialisation. Higher npoly leads to a more accurate transit model, but also increases computation time. Increasing the number of limb darkening coefficients doesn’t significantly increase computation time, but
Notes:
A flexible model that can model limb darkening accurately.
Somewhat slower to evaluate than the specialized models.
PyTransit implements a special “transmission spectroscopy mode” for the general model that accelerates the transit model evaluation significantly for transmission spectroscopy where the light curves are computed from a spectroscopic time series.
The four-coefficient model presented in Mandel & Agol (ApJ 580, 2001) is not implemented in PyTransit since the Giménez model offers the same functionality with higher flexibility.
Chromosphere model#
Optically thin shell model (pytransit.ChromosphereModel
and pytransit.ChromosphereModelCL
) by
Schlawin et al. (ApJL 722, 2010) to model a transit
over a chromosphere.