ExoCTK is an open-source, modular data analysis package focused primarily on atmospheric characterization of exoplanets. The subpackages included are:
- Transit Lightcurve Fitter
- Limb Darkening Calculator
- Groups and Integrations Calculator
The lightcurve_fitting tool fits large numbers of spectroscopic light curves simultaneously while sharing model parameters across wavelengths and visits. It includes multiple uncertainty estimation algorithms and a comprehensive library of physical and systematic model components that are fully customizable.
The limb_darkening tool calculates limb-darkening coefficients for a specified stellar model, plotting results versus µ and wavelength. It uses high spectral resolution stellar atmospheric models, which are a necessity given JWST's expected precision.
Coefficients of the quadratic and 4-parameter limb darkening profiles for the Phoenix ACES stellar atmosphere model [4000, 4.5, 0] through the WFC3_IR.G141 grism.
The groups_integrations tool is a JWST observation planning tool designed with
exoplanet observations in mind. Given a potential observation (which requires
transit time, and an estimate of model and magnitude for the
host star, and specifics of instrument setup) it's simple to get an optimized
groups and integrations plan for the observation. The example notebook also
outlines cases for batch demos -- testing many transits/sources in a given instrument
setup, or figuring out which instrument setup is best for a given transit.
The Groups and Integrations Calculator runs with pre-sampled pandeia data in the background -- so it can have the power of those carefully built instrument models, but still run 100 times faster.
The following are instructions on how to install the exoctk package for both users and contributors. The exoctk repository provides a conda environment containing all of the dependencies needed to install and execute the exoctk software.
You must first have a working installation of anaconda or miniconda for Python 3. If you do not yet have this on your system, you can visit the following links for download and installation instructions:
The files needed for the environment installation are available within the exoctk package itself. If you have not done so already, download and install the exoctk package, either by pip:
pip install exoctk
or by cloning the exoctk repository directly:
git clone https://github.com/ExoCTK/exoctk.git cd exoctk python setup.py install
Following the installation of the exoctk package, you can install the conda environment via the env/environment-<PYTHON_VERSION>.yml files (relative to the parent directory of the repository). Note that there is are separate environment files for each version of python that exoctk supports. First, one should ensure that their version of conda is up to date:
conda update conda
Next, one should activate the base environment:
source activate base
Next, one can create the exoctk conda environment via the appropriate environment-<PYTHON_VERSION>.yml file:
conda env create -f environment-<PYTHON_VERSION>.yml
where <PYTHON_VERSION> is the version of python you are using (e.g. environment-3.6.yml)
Lastly, one can activate the newly-created environment with:
source activate exoctk-<PYTHON_VERSION>
where again, <PYTHON_VERSION> is the version of python you are using (e.g. exoctk-3.6)
If you find that the exoctk conda is missing a required dependency, please feel free to submit a GitHub Issue detailing the problem.