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.

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.

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

IN PROGRESS — 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 1.3

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 Star 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.

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.