Welcome to the GSFC Exoplanet Modeling and Analysis Center (EMAC)

EMAC serves as a catalog, repository and integration platform for modeling and analysis resources focused on the study of exoplanet characteristics and environments.

EMAC is a key project of the GSFC Sellers Exoplanet Environments Collaboration (SEEC). The P.I. is Avi Mandell, and the Deputy P.I. is Eric Lopez; more information on EMAC staffing and organization will be posted shortly.

ATMO Exoplanet-Specific Grid

Jayesh Goyal et al. Atm

A grid of forward model transmission spectra, adopting an isothermal temperature-pressure profile, alongside corresponding equilibrium chemical abundances for 117 observationally significant hot exoplanets (equilibrium temperatures of 547–2710 K). This model grid has been developed using a 1D radiative–convective–chemical equilibrium model termed ATMO, with up-to-date high-temperature opacities.

ATMO Generic Grid @ ExoCTK

Jayesh Goyal et al. Atm

A generic model grid of planetary transmission spectra, scalable to a wide range of H2/He dominated atmospheres. The grid is computed using the 1D/2D atmosphere model ATMO for two different chemical scenarios, first considering local condensation only, secondly considering global condensation and removal of species from the atmospheric column (rainout). Using the model grid as a framework, we allow you to rescale your models with custom temperature, gravity, and radius values. The web interface is hosted and maintained by the STScI Exoplanet Characterization ToolKit.


Claire et al. Atm

IN PROGRESS — Atmos is a packaged photochemical model and climate model used to understand the vertical structure of various terrestrial atmospheres. Its photochemical model calculates the profiles of various chemicals in the atmosphere, including both gaseous and aerosol phases. Its climate model calculates the temperature profile of the atmosphere. While individually these models may be run for useful information, when coupled they offer a detailed analysis of atmospheric steady-state structures.


Laura Kreidberg Fit

BATMAN is a Python package for fast calculation of exoplanet transit light curves. The package supports calculation of light curves for any radially symmetric stellar limb darkening law, using a new integration algorithm for models that cannot be quickly calculated analytically. In typical use, batman can calculate a million model light curves in well under 10 minutes for any limb darkening profile.

Coronagraphic Mission Simulator

Arney et al. Obs

This simplified coronagraph simulator tool is based on the coronagraph noise model in Robinson et al. 2016, adapted by J. Lustig-Yaeger, G. Arney and J. Tumlinson. The tool was developed for the LUVOIR mission concept, but can be used to simulated observations for any exoplanet coronagraphy mission.


Emily Sandford, David Kipping Fit

EightBitTransit is an MIT-licensed Cython code that: - Can calculate the light curve of any pixelated image transiting a star; - Can invert a light curve to recover the "shadow image" that produced it. The methodology behind the code is available in Sandford & Kipping 2018 (https://arxiv.org/pdf/1812.01618.pdf).


Feinstein, A. D., Montet, B. T., Foreman-Mackey, D., et al.

eleanor is a python package to extract target pixel files from TESS Full Frame Images and produce systematics-corrected light curves for any star observed by the TESS mission. In its simplest form, eleanor takes a TIC ID, a Gaia source ID, or (RA, Dec) coordinates of a star observed by TESS and returns, as a single object, a light curve and accompanying target pixel data.

Paper: Feinstein et al., eleanor: An open-source tool for extracting light curves from the TESS Full-Frame Images, 2019

EqTide: Tidal Evolution Simulator

Rory Barnes Int Orb

EqTide simulates the tidal evolution of two bodies using the equilibrium tide theory. Six ordinary differential equations for the semi-major axis, eccentricity, both rotation rates, and both obliquities are integrated for a user-specified amount of time. Additionally the tidal power generated in each body is calculated. EqTide specifically simulates the constant-phase-lag model of Ferraz-Mello et al. (2008) and the constant-time-lag model of Leconte et al. (2010).


Jason Eastman et al. Star Fit

EXOFASTv2 is capable of fitting an arbitrary number of planets, radial velocity data sets, astrometric data sets, and/or transits observed with any combination of wavelengths. We model the star simultaneously in the fit and provide several state-of-the-art ways to constrain its properties, including taking advantage of the now-ubiquitous all-sky catalog photometry and Gaia parallaxes. EXOFASTv2 can model the star by itself, too. Multi-planet systems are modeled self-consistently with the same underlying stellar mass that defines their semi-major axes through Kepler's law and the planetary period. Transit timing, duration, and depth variations can be modeled with a simple command line option. The code is written in IDL, and includes an executable that can be run freely and legally without an IDL license or any knowledge of the language. Extensive documentation and tutorials are included in the distribution for a variety of example fits. Advanced amateurs and undergrads have successfully performed sophisticated global fits of complex planetary systems with EXOFASTv2. It is therefore a powerful tool for education and outreach as well as the broader professional community.

ExoPlanetary Spectrum Generator

Jonathan Brande, Geronimo Villanueva et al. Atm RT Obs

The ExoPlanetary Spectrum Generator (ExoPSG) provides a streamlined interface to Goddard's Planetary Spectrum Generator, modified for exoplanet-specific work. It allows users to interact with the PSG API and make use of exoplanetary templates and models.

Exoplanet Boundaries Calculator 1.1

Kopparapu et al. Atm

The Exoplanet Boundaries Calculator (EBC) is an online calculator that provides condensation boundaries (in stellar fluxes) for ZnS, H2O, CO2 and CH4 for the following planetary radii that represent transition to different planet regimes: 0.5, 1, 1.75, 3.5, 6, and 14.3 RE. The purpose is to classify planets into different categories based on a species condensing in a planet's atmosphere. These boundaries are applicable only for G-dwarf stars.

Exoplanet Composition Interpolator 1.0

Eric Lopez, NASA GSFC Int

This tool allows the user to load pre-computed planet evolution models and interpolate between those models to explore the possible structures of transiting exoplanets. Select a planet mass, radius, age, and irradiation and this tool will estimate it’s possible present-day gaseous envelope mass, rocky core mass, and thermal brightness.


Savransky et al. Obs

EXOSIMS is a modular, open source, Python-based framework for the simulation and analysis of exoplanet imaging space missions. The base code is highly extensible and allows for the end-to-end simulation of imaging missions, taking into account details about the spacecraft, its orbit, the instrumentation, the assumed population of exoplanets, and the mission operating rules.


Gabrielle Suissa, David Kipping Int

IN PROGRESS — HARDCORE exploits boundary conditions on exoplanet internal composition to solve for the minimum and maximum core radius fraction based on mass and radius limits.


Malik et al. Atm RT

HELIOS is an open-source radiative transfer code designed to study exoplanetary atmospheres, from rocky terrestrial planets to ultra-hot Jupiters. For given opacities and planetary parameters, HELIOS finds the atmospheric temperature profile in radiative-convective equilibrium and the synthetic planetary emission spectrum. HELIOS is written in Python, with the core computations parallelized to run on a GPU. HELIOS is part of the Exoclimes Simulation Platform.

LAPS: The Live Atmosphere-of-Planets Simulator

Martin Turbet (LMD), Cédric Schott (ESEP) and the LMD team Atm RT

LAPS is a new tool that was developed to easily simulate the climate of planets similar to Earth (i.e., terrestrial but not giant planets). This model is based on the LMD (Laboratoire de Météorologie Dynamique) Global Climate Model (GCM), a complex 3-D numerical model of climate solving equations of thermodynamics, radiative transfer and hydrodynamics. This complex 3-D model has been simplified to a 1-D code (Turbet et al. 2016, 2017), which is therefore much faster to run and can now be used online in an interactive fashion.


Vinícius, Barentsen, Hedges, et al. Fit

IN PROGRESS — The lightkurve Python package offers a beautiful and user-friendly way to analyze astronomical flux time series data, in particular the pixels and lightcurves obtained by NASA’s Kepler, K2, and TESS missions.

Multiplanet Yield Tool

Christopher Stark, Jason Tumlinson, et al. Obs

This tool visualizes the results of detailed exoplanet mission yield simulations, calculated using the planet classifications from Kopparapu et al. (in preparation). The methodology is described in Stark et al. (2014), ApJ, 795, 122 and Stark et al. (2015), ApJ, 808, 149. The python code to render the results was written by Jason Tumlinson. This tool was developed to support the LUVOIR Mission Concept Study Report, pending submission to the Astro2020 Decadal Survey.

Multipolator - Model Grid Interpolator

Carlos E. Munoz Romero Fit

The multipolator package is a fast routine written in C that performs N-dimensional interpolation on a grid of astronomical models. The code finds the two closest neighbors to the input parameters in each dimension, constructs an N-dimensional hypercube, and interpolates the nearest models through inverse distance weighting.

PandExo JWST/HST Simulator

Batalha et al. Obs

PandExo is both an online tool and a Python package for generating instrument simulations of JWST's NIRSpec, NIRCam, NIRISS and NIRCam and HST WFC3. It uses throughput calculations from STScI's Exposure Time Calculator, Pandeia.


Paul Mollière Atm RT Fit

petitRADTRANS (pRT) is a Python package for calculating transmission and emission spectra of exoplanets, at low (𝜆/Δ𝜆=1000) and high (𝜆/Δ𝜆=10^6) resolution, for clear and cloudy atmospheres. pRT offers a large variety of atomic and molecular gas opacities, cloud cross-sections from optical constants, or parametrized cloud models using either opacity power laws or grey cloud decks. The code also allows to calculate emission and transmission contribution functions, and contains a PHOENIX/ATLAS9 spectral library for host stars to calculate planet-to-star contrasts. The code is documented, and a tutorial with many examples exists on the code website. Implemented examples for MCMC retrievals with pRT can be found on the code website.


Natasha Batalha, Mark Marley, Nikole Lewis, Jonathon Fortney Atm RT

IN PROGRESS — An open-source radiative transfer model for computing the reflected light of exoplanets at any phase geometry, called PICASO: Planetary Intensity Code for Atmospheric Scattering Observations. This code, written in Python, has heritage from a decades old, well-known Fortran model used for several studies of planetary objects within the Solar System and beyond. We have adopted it to include several methodologies for computing both direct and diffuse scattering phase functions, and have added several updates including the ability to compute Raman scattering spectral features.

Planetary Spectrum Generator

Villanueva et al. Atm RT Obs

The Planetary Spectrum Generator (PSG) is an online tool for synthesizing planetary spectra (atmospheres and surfaces) for a broad range of wavelengths (100 nm to 100 mm, UV/Vis/near-IR/IR/far-IR/THz/sub-mm/Radio) from any observatory (e.g., JWST, ALMA, Keck, SOFIA).

PLATON: PLanetary Atmospheric Tool for Observer Noobs

Michael Zhang, Yayaati Chachan, Eliza Kempton, Heather Knutson Atm RT Fit

PLATON is a Python package that can calculate transmission and emission spectra for exoplanets, as well as retrieve atmospheric characteristics based on observed spectra. PLATON is easy to install and use, with common use cases taking no more than a few lines of code. It is also fast, with the forward model taking less than 100 ms and a typical retrieval finishing in ~10 min on an ordinary desktop. PLATON supports the most common atmospheric parameters, such as temperature, metallicity, C/O ratio, cloud-top pressure, and scattering slope. It also has less commonly included features, such as a Mie scattering cloud model and unocculted starspot corrections.


William Fawcett et al. Atm

PyATMOS is a software package that can used to configure and run the Virtual Planetary Laboratories' ATMOS software, which is an exoplanetary atmosphere simulator. As the name suggests, PyATMOS is written in python allowing easy user configuration and running. The software is optionally configurable with docker and therefore can be used on any machine with docker and python installed, regardless of the operating system. PyATMOS can be used in "single-use" mode, i.e. simulating a single exoplanet atmosphere with a given set of atmospheric parameters, but also in a parallel mode, whereby a grid of possible parameters for many atmospheres is supplied, and PyATMOS will explore this parameter space and produce a database of the results. The parallelised mode was was designed with cloud computing in mind, and can be configured to run in parallel with any number of additional machines, allowing rapid exploration of the desired parameter space.

PyATMOS NExSci Repository

William Fawcett et al. Atm

The PyATMOS dataset, hosted at NExSci, comprises around 125,000 simulated 1-D exoplanet atmospheres. The results for each atmosphere include temperature, pressure, gas concentration and gas flux profiles, each as a function of altitude. All of these exoplanets are based around an Earth-like planet that orbits a star similar to the Sun, but with different gas mixtures in their atmospheres. The atmospheres were generated using the PyATMOS code, which in turn uses Atmos (the atmosphere generator). The parameter space of possible atmospheres was created by incrementally varying the concentrations of the following gasses: Carbon dioxide (CO2), Oxygen (O2), Water vapour (H2O), Methane (CH4), Hydrogen (H2), Nitrogen (N2); and for each point in the parameter space an atmosphere was simulated. Other gases with negligible concentrations, such as ozone (O3), were not varied. The planet's composition, orbital parameter and stellar parameters were also not varied.

Reflection Spectra Repository for Cool Giant Planets

Ryan J. MacDonald; Mark S. Marley; Jonathan J. Fortney; Nikole K. Lewis Atm

We present an extensive parameter space survey of the prominence of H2O in reflection spectra of cool giant planets. We explore the influence of a wide range of effective temperatures, gravities, metallicities, and sedimentation efficiencies, providing a grid of >50,000 models for the community. Our models range from Teff = 150 → 400 K, log(g) = 2.0 - 4.0 (cgs), fsed = 1 - 10, and log(m) = 0.0 - 2.0 ́ solar. We discretize this parameter space into intervals of ΔTeff = 10 K, Δlog(g) = 0.1 dex, Δfsed = 1, and Δlog(m) = 0.5 dex, generating reflection spectra both with and without H2O opacity.

STARRY: Analytic Occultation Light Curves

Rodrigo Luger, Eric Agol, Daniel Foreman-Mackey, David P. Fleming, Jacob Lustig-Yaeger, Russell Deitrick Obs Fit

The STARRY code package enables the computation of light curves for various applications in astronomy: transits and secondary eclipses of exoplanets, light curves of eclipsing binaries, rotational phase curves of exoplanets, light curves of planet-planet and planet-moon occultations, and more. By modeling celestial body surface maps as sums of spherical harmonics, STARRY does all this analytically and is therefore fast, stable, and differentiable. Coded in C++ but wrapped in Python, STARRY is easy to install and use.

Transit Least Squares

Michael Hippke, René Heller Fit

The Transit Least Squares (TLS) algorithm is a new method to detect planetary transits from time-series photometry. While the commonly used Box Least Squares (BLS, Kovács et al. 2002) algorithm searches for rectangular signals in stellar light curves, TLS searches for transit-like features with stellar limb-darkening and including the effects of planetary ingress and egress. Moreover, TLS analyses the entire, unbinned data of the phase-folded light curve. These improvements yield a ~10 % higher detection efficiency (and similar false alarm rates) compared to BLS. The higher detection efficiency of our freely available Python implementation comes at the cost of higher computational load, which we partly compensate by applying an optimized period sampling and transit duration sampling, constrained to the physically plausible range. A typical Kepler K2 light curve, encompassing 90 d of observations at a cadence of 30 min, can be searched with TLS in 10 seconds of clock time on a standard laptop computer, just as with BLS.

TROPF: Tidal Response Of Planetary Fluids

Robert Tyler Atm Int

The TROPF (Tidal Response Of Planetary Fluids) Software Package is a Matlab/Octave package to enable efficient terrestrial fluid tidal studies across a wide range of parameter space. TROPF includes several different solutions to the governing equations in classical tidal theory, and can calculate millions of such solutions on several-minute-long timescales. A comprehensive manual is included in the distribution directory. To help improve the development of TROPF, or become involved in future releases, please send feedback to rtyler@umbc.edu.

VPLanet: Planetary System Evolution Simulator

Rory Barnes et al. Star Atm Int Orb

VPLanet is open source software to simulate planetary system evolution, with a focus on habitability. Physical models, typically consisting of ordinary differential equations, are coupled together to simulate evolution of a wide variety of systems. Eleven physics modules are included that model internal, atmospheric, rotational, orbital, stellar, and galactic processes. Many of these modules can be coupled to simultaneously simulate the evolution of terrestrial planets, gaseous planets, and stars. The code is validated by reproducing a selection of observations and past results.