PyORBIT version 6.0 by Luca Malavolta - September 2018
New Version 6 correctly implements model selection with nested sampling performed by
PolyChord. Because of the way the software has been structured, each model must be contained in a different
yaml file, i.e. the number of planets is not an hyperparameter but it must be fixed a priori. However, the same
yaml file can be used to run
Documentation Some incomplete documentation is available here. For any doubt, feel free to contact me at luca.malavolta_at_unipd.it, I'll be happy to work out together any problem that may arise during installation or usage of this software.
PyORBIT handles several kinds of datasets, such as radial velocity (RV), activity indexes, and photometry, to simultaneously characterize the orbital parameters of exoplanets and the noise induced by the activity of the host star. RV computation is performed using either non-interacting Kepler orbits or n-body integration. Stellar activity can be modeled either with sinusoids at the rotational period and its harmonics or gaussian process. Offsets and systematics in measurements from several instruments can be modeled as well. Thanks to the modular approach, new methods for stellar activity modeling or parameter estimation can be easily incorporated into the code.
Models Any of these models can be applied to a dataset. The user can choose which model should be use for each dataset.
Gaussian Processesfor RV or photometry (shared or independent hyperparameter)
Polynomial trendswith user-defined order
Correlationwith activity indexes (or any other dataset)
Sinusoids(independent or shared amplitudes and periods)
Celeritesupport available (untested)
Priors These priors can be applied to any of the parameters (it's up to the user to choice the appropriate ones):
Uniformdefault prior for all the parameters
Modified Jeffreys priors are actually
Truncated Jeffreys and
Truncated Modified Jeffreys, with truncation defined by the boundaries of the parameter space.
The user can choice between
Logarithmic. Note that in the second case the parameter space is transformed into base-2 logarithm.