August 11, 2023 Alex Howe & Chris Stark NASA Goddard Space Flight Center
ExoVista is a hybrid Python/C++ software package based on an earlier IDL/C iteration that generates synthetic exoplanetary systems. ExoVista models exoplanet atmospheres in reflected light, stellar spectra using Kurucz stellar atmosphere models, and debris disks in scattered light using realistic spatial distributions and optical properties. Planets can be drawn from measured/extrapolated Kepler occurrence rates (Dulz et al. 2020) and are checked for basic stability criteria; debris disks are dynamically quasi-self-consistent with the underlying planetary system. All bodies are integrated with a Bulirsch-Stoer integrator to determine their barycentric velocities, positions, and orbits. The output product is a multi-extension fits file that contains all of the information necessary to generate a spectral data cube of the system for direct imaging simulations of coronagraphs/starshades, as well as position/velocity data for simulation of RV, astrometric, and transit (pending) data sets.
To run the main modules of ExoVista, you must have a Python interpreter (Python 3.8 or higher recommended). You will also need to have installed, in addition to the “standard” suite of Python modules, the Python packages scipy, astropy, and cython. The multiprocessing package is also needed if you wish to use ExoVista with parallel processing, although ExoVista can run as a serial code without it.
ExoVista also requires a C++ compiler. For Linux users, g++ is usually available. For Mac OS users, it is recommended to install Apple’s XCode to obtain a compiler. For Windows users, it is recommended to use the Microsoft Visual C/C++ compiler. Other tools such as those found in MinGW or Cygwin may work, but these have not been tested.
To install ExoVista, download the current version of the ExoVista package from the Github repository into the desired directory on your local machine.
Open a terminal window, navigate to the “src” subdirectory in the directory containing the ExoVista code, and compile the disk imaging module by typing the following command:
python setup.py build_ext --inplace
Cython should automatically call your C++ compiler and generate the files “wrapImage.cpp” and “wrapIntegrator.cpp” on your machine in the src subdirectory. If this fails, you may need to uncomment and edit the following lines in “setup.py” to reflect your local compiler environment (see the Cython documentation for more information):
import os
os.environ['CC'] = 'gcc'
os.environ['CXX'] = 'g++'
Once the wrapImage and wrapIntegrator modules are built successfully, you will be ready to run all ExoVista modules.