arXiv subjects

Emily Rauscher

Publications and source records attributed to Emily Rauscher.

At least 73 records · Page 4Linked to original sources

arXiv2021

Exploring the Effects of Active Magnetic Drag in a GCM of the Ultra-Hot Jupiter WASP-76b

Ultra-hot Jupiters represent an exciting avenue for testing extreme physics and observing atmospheric circulation regimes not found in our solar system. Their high temperatures result in thermally ionized particles embedded in atmospheric winds interacting with the planet's interior magnetic field by generating current and experiencing bulk Lorentz force drag. Previous treatments of magnetic drag in 3D General Circulation Models (GCMs) of ultra-hot Jupiters have mostly been uniform drag timescales applied evenly throughout the planet, which neglects the strong spatial dependence of these magnetic effects. In this work, we apply our locally calculated active magnetic drag treatment in a GCM of the planet WASP-76b. We find the effects of this treatment to be most pronounced in the planet's upper atmosphere, where strong differences between the day and night side circulation are present. These circulation effects alter the resulting phase curves by reducing the hotspot offset and increasing the day-night flux contrast. We compare our models to Spitzer phase curves which imply a magnetic field of at least 3 G for the planet. We additionally contrast our results to uniform drag timescale models. This work highlights the need for more careful treatment of magnetic effects in atmospheric models of hot gas giants.

astro-ph.EP↗

arXiv2021

A solar C/O and sub-solar metallicity in a hot Jupiter atmosphere

Measurements of the atmospheric carbon (C) and oxygen (O) relative to hydrogen (H) in hot Jupiters (relative to their host stars) provide insight into their formation location and subsequent orbital migration. Hot Jupiters that form beyond the major volatile (H2O/CO/CO2) ice lines and subsequently migrate post disk-dissipation are predicted have atmospheric carbon-to-oxygen ratios (C/O) near 1 and subsolar metallicities, whereas planets that migrate through the disk before dissipation are predicted to be heavily polluted by infalling O-rich icy planetesimals, resulting in C/O < 0.5 and super-solar metallicities. Previous observations of hot Jupiters have been able to provide bounded constraints on either H2O or CO, but not both for the same planet, leaving uncertain the true elemental C and O inventory and subsequent C/O and metallicity determinations. Here we report spectroscopic observations of a typical transiting hot Jupiter, WASP-77Ab. From these, we determine the atmospheric gas volume mixing ratio constraints on both H2O and CO (9.5$\times 10^{-5}$ - 1.5$\times 10^{-4}$ and 1.2$\times 10^{-4}$ - 2.6$\times 10^{-4}$, respectively). From these bounded constraints, we are able to derive the atmospheric C/H (0.35$^{+0.17}_{-0.10}$ $\times$ Solar) and O/H (0.32 $^{+0.12}_{-0.08}$ $\times$ Solar) abundances and the corresponding atmospheric carbon-to-oxygen ratio (C/O=0.59$\pm$0.08; the solar value is 0.55). The sub-solar (C+O)/H (0.33$^{+0.13}_{-0.09}$ $\times$ Solar) is suggestive of a metal-depleted atmosphere relative to what is expected for Jovian-like planets while the near solar value of C/O rules out the disk-free migration/C-rich atmosphere scenario.

astro-ph.EP↗

arXiv2021

Modeling the high-resolution emission spectra of clear and cloudy non-transiting hot Jupiters

The advent of high-resolution spectroscopy as a method for exoplanet atmospheric characterization has expanded our capability to study non-transiting planets, increasing the number of planets accessible for observation. Many of the most favorable targets for atmospheric characterization are hot Jupiters, where we expect large spatial variation in physical conditions such as temperature, wind speed, and cloud coverage, making viewing geometry important. Three-dimensional models have generally simulated observational properties of hot Jupiters assuming edge-on viewing, which neglects planets without near edge-on orbits. As the first investigation of how orbital inclination manifests in high-resolution emission spectra, we use a General Circulation Model to simulate the atmospheric structure of Upsilon Andromedae b, a non-transiting hot Jupiter. In order to accurately capture scattering from clouds, we implement a generalized two-stream radiative transfer routine for inhomogeneous multiple scattering atmospheres. We compare models with and without clouds, as cloud coverage intensifies spatial variations. Cloud coverage increases both the net Doppler shifts and the variation of the continuum flux amplitude over the course of the planet's orbit. As orbital inclination decreases, four key features also decrease in both the clear and cloudy models: 1) the average continuum flux level, 2) the amplitude of the variation in continuum with orbital phase, 3) net Doppler shifts of spectral lines, and 4) Doppler broadening in the spectra. Models capable of treating inhomogeneous cloud coverage and different viewing geometries are critical in understanding high-resolution emission spectra, enabling an additional avenue to investigate these extreme atmospheres.

astro-ph.EP↗

arXiv2021

Five new hot-Jupiter transits investigated with Swift-UVOT

Short wavelength exoplanet transit measurements have been used to probe mass-loss in exoplanet atmospheres. We present the Swift-UVOT transit light curves for five hot Jupiters orbiting UV-bright F-type stars: XO-3, KELT-3, WASP-3, WASP-62, and HAT-P-6. We report one positive transit detection of XO-3b and one marginal detection of KELT-3b. We place upper limits on the remaining three transit depths. The planetary radii derived from the NUV transit depths of both potential detections are 50-100% larger than their optical radius measurements. We examine the ratio $R_{\rm NUV}/R_{\rm opt}$ for trends as a function of estimated mass-loss rate, which we derive from X-ray luminosity obtained from the Swift-XRT, or XMM-Newton in the case of WASP-62. We find no correlation between the energy-limited photoevaporative mass-loss rate and the $R_{\rm NUV}/R_{\rm opt}$ ratio. We also search for trends based on the equilibrium temperature of the hot Jupiters. We find a possible indication of a transition in the $R_{\rm NUV}/R_{\rm opt}$ ratio around $T_{\rm eq} = 1700~{\rm K}$, analogous to the trends found for NIR water features in transmission spectra. This might be explained by the formation of extended cloud decks with silicate particles $\leq 1~μ{\rm m}$. We demonstrate that the Swift-UVOT filters could be sensitive to absorption from aerosols in exoplanet atmospheres.

astro-ph.EP↗

arXiv2021

SPORK That Spectrum: Increasing Detection Significances from High-Resolution Exoplanet Spectroscopy with Novel Smoothing Algorithms

Spectroscopic studies of planets outside of our own solar system provide some of the most crucial information about their formation, evolution, and atmospheric properties. In ground-based spectroscopy, the process of extracting the planet's signal from the stellar and telluric signal has proven to be the most difficult barrier to accurate atmospheric information. However, with novel normalization and smoothing methods, this barrier can be minimized and the detection significance dramatically increased over existing methods. In this paper, we take two examples of CRIRES emission spectroscopy taken of HD 209458 b and HD 179949 b and apply SPORK (SPectral cOntinuum Refinement for telluriKs) and iterative smoothing to boost the detection significance from 5.78 to 9.71 sigma and from 4.19 sigma to 5.90 sigma, respectively. These methods, which largely address systematic quirks introduced by imperfect detectors or reduction pipelines, can be employed in a wide variety of scenarios, from archival data sets to simulations of future spectrographs.

astro-ph.EP↗

arXiv2021

Spitzer phase curve observations and circulation models of the inflated ultra-hot Jupiter WASP-76b

The large radii of many hot Jupiters can only be matched by models that have hot interior adiabats, and recent theoretical work has shown that the interior evolution of hot Jupiters has a significant impact on their atmospheric structure. Due to its inflated radius, low gravity, and ultra-hot equilibrium temperature, WASP-76b is an ideal case study for the impact of internal evolution on observable properties. Hot interiors should most strongly affect the non-irradiated side of the planet, and thus full phase curve observations are critical to ascertain the effect of the interior on the atmospheres of hot Jupiters. In this work, we present the first Spitzer phase curve observations of WASP-76b. We find that WASP-76b has an ultra-hot day side and relatively cold nightside with brightness temperatures of $2471 \pm 27~\mathrm{K}$/$1518 \pm 61~\mathrm{K}$ at $3.6~\micron$ and $2699 \pm 32~\mathrm{K}$/$1259 \pm 44~\mathrm{K}$ at $4.5~\micron$, respectively. These results provide evidence for a dayside thermal inversion. Both channels exhibit small phase offsets of $0.68 \pm 0.48^{\circ}$ at $3.6~\micron$ and $0.67 \pm 0.2^{\circ}$ at $4.5~μ\mathrm{m}$. We compare our observations to a suite of general circulation models that consider two end-members of interior temperature along with a broad range of frictional drag strengths. Strong frictional drag is necessary to match the small phase offsets and cold nightside temperatures observed. From our suite of cloud-free GCMs, we find that only cases with a cold interior can reproduce the cold nightsides and large phase curve amplitude at $4.5~\micron$, hinting that the hot interior adiabat of WASP-76b does not significantly impact its atmospheric dynamics or that clouds blanket its nightside.

astro-ph.EP↗

arXiv2021

Irradiation-driven escape of primordial planetary atmospheres I. The ATES photoionization hydrodynamics code

Intense X-ray and ultraviolet stellar irradiation can heat and inflate the atmospheres of closely orbiting exoplanets, driving mass outflows that may be significant enough to evaporate a sizable fraction of the planet atmosphere over the system lifetime. The recent surge in the number of known exoplanets, together with the imminent deployment of new ground and space-based facilities for exoplanet discovery and characterization, requires a prompt and efficient assessment of the most promising targets for intensive spectroscopic follow-ups. To this purpose, we developed ATES (ATmospheric EScape); a new hydrodynamics code that is specifically designed to compute the temperature, density, velocity and ionization fraction profiles of highly irradiated planetary atmospheres, along with the current, steady-state mass loss rate. ATES solves the one-dimensional Euler, mass and energy conservation equations in radial coordinates through a finite-volume scheme. The hydrodynamics module is paired with a photoionization equilibrium solver that includes cooling via bremsstrahlung, recombination and collisional excitation/ionization for the case of a primordial atmosphere entirely composed of atomic hydrogen and helium, whilst also accounting for advection of the different ion species. Compared against the results of 14 moderately-to-highly irradiated planets simulated with The PLUTO-CLOUDY Interface (TPCI), ATES yields remarkably good agreement at a significantly smaller fraction of the computational time. A convergence study shows that ATES recovers stable, steady-state hydrodynamic solutions for systems with $\log(-ϕ_p) \lesssim 12.9 + 0.17\log F_{\rm XUV}$. Incidentally, atmospheres of systems above this threshold are generally thought to be undergoing Jeans escape. The code, which also features a user-friendly graphic interface, is available publicly as an online repository.

astro-ph.EP↗

arXiv2021

Signatures of Clouds in Hot Jupiter Atmospheres: Modeled High Resolution Emission Spectra from 3D General Circulation Models

Observations of scattered light and thermal emission from hot Jupiter exoplanets have suggested the presence of inhomogeneous aerosols in their atmospheres. 3D general circulation models (GCMs) that attempt to model the effects of aerosols have been developed to understand the physical processes that underlie their dynamical structures. In this work, we investigate how different approaches to aerosol modeling in GCMs of hot Jupiters affect high-resolution thermal emission spectra throughout the duration of the planet's orbit. Using results from a GCM with temperature-dependent cloud formation, we calculate spectra of a representative hot Jupiter with different assumptions regarding the vertical extent and thickness of clouds. We then compare these spectra to models in which clouds are absent or simply post-processed (i.e., added subsequently to the completed clear model). We show that the temperature-dependent treatment of clouds in the GCM produces high-resolution emission spectra that are markedly different from the clear and post-processed cases -- both in the continuum flux levels and line profiles -- and that increasing the vertical extent and thickness of clouds leads to bigger changes in these features. We evaluate the net Doppler shifts of the spectra induced by global winds and the planet's rotation and show that they are strongly phase-dependent, especially for models with thicker and more extended clouds. This work further demonstrates the importance of radiative feedback in cloudy atmospheric models of hot Jupiters, as this can have a significant impact on interpreting spectroscopic observations of exoplanet atmospheres.

astro-ph.EP↗

arXiv2020

Clouds in Three-Dimensional Models of Hot Jupiters Over a Wide Range of Temperatures I: Thermal Structures and Broadband Phase Curve Predictions

Using a general circulation model (GCM), we investigate trends in simulated hot Jupiter atmospheres for a range of irradiation temperatures (1,500 - 4,000 K), surface gravities (10 and 40 m s-2), and cloud conditions. Our models include simplified temperature-dependent clouds with radiative feedback and show how different cloud compositions, vertical thicknesses, and opacities shape hot Jupiters atmospheres by potentially increasing planetary albedos, decreasing photospheric pressures and nightside temperatures, and in some cases producing strong dayside thermal inversions. With decreasing irradiation, clouds progressively form on the nightside and cooler western limb followed by the eastern limb and central dayside. We find that clouds significantly modify the radiative transport and affect the observable properties of planets colder than T_irr ~ 3,000~K (T_eq~2,100 K) depending on the clouds' vertical extent. The precise strength of expected effects depends on the assumed parameters, but trends in predicted phase curves emerge from an ensemble of simulations. Clouds lead to larger phase curve amplitudes and smaller phase curve offsets at IR wavelengths, compared to cloud-free models. At optical wavelengths, we predict mostly westward phase curve offsets at intermediate temperatures (T_irr ~ 2,000 - 3,500 K) with clouds confined to the nightside and western limb. If clouds are vertically compact (i.e. on order of a pressure scale height in thickness), their distributions and effects become more complicated as different condensates form at different heights -- some too deep to significantly affect the observable atmosphere. Our results have implications for interpreting the diversity of phase curve observations of planets with T_irr <~3,000~K.

astro-ph.EP↗

arXiv2020

Keys of a Mission to Uranus or Neptune, the Closest Ice Giants

Uranus and Neptune are the archetypes of "ice giants", a class of planets that may be among the most common in the Galaxy. They hold the keys to understand the atmospheric dynamics and structure of planets with hydrogen atmospheres inside and outside the solar system; however, they are also the last unexplored planets of the Solar System. Their atmospheres are active and storms are believed to be fueled by methane condensation which is both extremely abundant and occurs at low optical depth. This means that mapping temperature and methane abundance as a function of position and depth will inform us on how convection organizes in an atmosphere with no surface and condensates that are heavier than the surrounding air, a general feature of giant planets. Owing to the spatial and temporal variability of these atmospheres, an orbiter is required. A probe would provide a reference atmospheric profile to lift ambiguities inherent to remote observations. It would also measure the abundances of noble gases which can be used to reconstruct the history of planet formation in the Solar System. Finally, mapping the planets' gravity and magnetic fields will be essential to constrain their global composition, atmospheric dynamics, structure and evolution. An exploration of Uranus or Neptune will be essential to understand these planets and will also be key to constrain and analyze data obtained at Jupiter, Saturn, and for numerous exoplanets with hydrogen atmospheres.

astro-ph.IM↗

arXiv2020

Eigenspectra: A Framework for Identifying Spectra from 3D Eclipse Mapping

Planetary atmospheres are inherently 3D objects that can have strong gradients in latitude, longitude, and altitude. Secondary eclipse mapping is a powerful way to map the 3D distribution of the atmosphere, but the data can have large correlations and errors in the presence of photon and instrument noise. We develop a technique to mitigate the large uncertainties of eclipse maps by identifying a small number of dominant spectra to make them more tractable for individual analysis via atmospheric retrieval. We use the eigencurves method to infer a multi-wavelength map of a planet from spectroscopic secondary eclipse light curves. We then apply a clustering algorithm to the planet map to identify several regions with similar emergent spectra. We combine the similar spectra together to construct an "eigenspectrum" for each distinct region on the planetary map. We demonstrate how this approach could be used to isolate hot from cold regions and/or regions with different chemical compositions in observations of hot Jupiters with the James Webb Space Telescope (JWST). We find that our method struggles to identify sharp edges in maps with sudden discontinuities, but generally can be used as a first step before a more physically motivated modeling approach to determine the primary features observed on the planet.

astro-ph.EP↗

arXiv2020

A Significant Increase in Detection of High-Resolution Emission Spectra Using a Three-Dimensional Atmospheric Model of a Hot Jupiter

High resolution spectroscopy has opened the way for new, detailed study of exoplanet atmospheres. There is evidence that this technique can be sensitive to the complex, three-dimensional (3D) atmospheric structure of these planets. In this work, we perform cross correlation analysis on high resolution (R~100,000) CRIRES/VLT emission spectra of the Hot Jupiter HD 209458b. We generate template emission spectra from a 3D atmospheric circulation model of the planet, accounting for temperature structure and atmospheric motions---winds and planetary rotation---missed by spectra calculated from one-dimensional models. In this first-of-its-kind analysis, we find that using template spectra generated from a 3D model produces a more significant detection (6.9 sigma) of the planet's signal than any of the hundreds of one-dimensional models we tested (maximum of 5.1 sigma). We recover the planet's thermal emission, its orbital motion, and the presence of CO in its atmosphere at high significance. Additionally, we analyzed the relative influences of 3D temperature and chemical structures in this improved detection, including the contributions from CO and H2O, as well as the role of atmospheric Doppler signatures from winds and rotation. This work shows that the Hot Jupiter's 3D atmospheric structure has a first-order influence on its emission spectra at high resolution and motivates the use of multi-dimensional atmospheric models in high-resolution spectral analysis.

astro-ph.EP↗

arXiv2020

Smaller than expected bright-spot offsets in Spitzer phase curves of the hot Jupiter Qatar-1b

We present \textit{Spitzer} full-orbit thermal phase curves of the hot Jupiter Qatar-1b, a planet with the same equilibrium temperature---and intermediate surface gravity and orbital period---as the well-studied planets HD 209458b and WASP-43b. We measure secondary eclipse of $0.21 \pm 0.02 \%$ at $3.6~μ$m and $0.30 \pm 0.02 \%$ at $4.5~μ$m, corresponding to dayside brightness temperatures of $1542^{+32}_{-31}$~K and $1557^{+35}_{-36}$~K, respectively, consistent with a vertically isothermal dayside. The respective nightside brightness temperatures are $1117^{+76}_{-71}$~K and $1167^{+69}_{-74}$~K, in line with a trend that hot Jupiters all have similar nightside temperatures. We infer a Bond albedo of $0.12_{-0.16}^{+0.14}$ and a moderate day-night heat recirculation efficiency, similar to HD 209458b. General circulation models for HD 209458b and WASP-43b predict that their bright-spots should be shifted east of the substellar point by tens of degrees, and these predictions were previously confirmed with \textit{Spitzer} full-orbit phase curve observations. The phase curves of Qatar-1b are likewise expected to exhibit eastward offsets. Instead, the observed phase curves are consistent with no offset: $11^{\circ}\pm 7^{\circ}$ at $3.6~μ$m and $-4^{\circ}\pm 7^{\circ}$ at $4.5~μ$m. The discrepancy in circulation patterns between these three otherwise similar planets points to the importance of secondary parameters like rotation rate and surface gravity, and the presence or absence of clouds, in determining atmospheric conditions on hot Jupiters.

astro-ph.EP↗

arXiv2020

From Super-Earths to Mini-Neptunes: Implications of a Surface on Atmospheric Circulation

It is well known that planets with radii between that of Earth and Neptune have been the most commonly detected to-date. To classify these planets as either terrestrial or gaseous, typically we turn to mass-radius relations and composition curves to determine the likelihood of such a planet being rocky or gaseous. While these methods have set a likely transition radius of approximately 1.5 R$_{\oplus}$, we cannot expect that any change between terrestrial and gaseous compositions will be a sharp cut-off, and composition curve predictions result in ambiguous designations for planets right near this transition radius. In this work we present 3D general circulation models of transition planets, wherein we study the effects of a surface on observable quantities such as the latitudinal variations and eclipse depths. We present our updated GCM, validated on the circulation of Earth, before discussing our modeling choices for this transition planet. Finally, we discuss the results of this study and explore the prospects of detecting the presence of a surface through observations of secondary eclipses in the future.

astro-ph.EP↗

arXiv2019

The High-Resolution Transmission Spectrum of HD 189733b Interpreted with Atmospheric Doppler Shifts from Three-Dimensional General Circulation Models

The signature of wind patterns caused by the interplay of rotation and energy redistribution in hot Jupiters is detectable at high spectral resolution, yet no direct comparison has been attempted between predictions from general circulation models (GCMs) and observed high-resolution spectra. We present the first of such comparisons on near-infrared transmission spectra of the hot Jupiter HD 189733b. Exploring twelve rotation rates and two chemical regimes, we have created model spectra from 3-D GCMs and cross-correlated them with the observed spectra. Comparing our models against those of HD 189733b, we obtain three key results: (1) we confirm CO and H$_2$O in the planet's atmosphere at a detection significance of 8.2$σ$; (2) we recover the signature of $\sim$km/s day-to-night winds at $\sim$mbar pressures; and (3) we constrain the rotation period of the planet to between 1.2 and 4.69 days (synchronous rotation (2.2 days) remains consistent with existing observations). Our results do not suffer from the shortcomings of 1-D models as cross correlation templates - mainly that these models tend to over-constrain the slower rotation rates and show evidence for anomalous blue shifts. Our 3-D models instead match the observed line-of-sight velocity of this planet by self-consistently including the effects of high-altitude day-to-night winds. Overall, we find a high degree of consistency between HD 189733b observations and our GCM-based spectra, implying that the physics and chemistry are adequately described in current 3-D forward models for the purpose of interpreting observations at high spectral resolution.

astro-ph.EP↗

arXiv2019

Modeled Temperature-Dependent Clouds with Radiative Feedback in Hot Jupiter Atmospheres

Using a general circulation model with newly implemented cloud modeling, we investigate how radiative feedback can self-consistently shape condensate cloud distributions, temperatures, and fluxes in a hot Jupiter atmosphere. We apply a physically motivated but simple parameterization of condensate clouds in which the temperature determines the cloud distribution, and we evaluate how different assumptions of vertical mixing and aerosol scattering parameters affect predictions. We compare results from cases in which the aerosols are simply included in the last step of the simulation (i.e. post-processed) to cases in which clouds and their radiative feedback are actively included throughout the duration of the simulation. When clouds and radiative feedback were actively included, cloud cover decreased at equatorial regions and increased towards the poles relative to the post-processed solutions. The resulting phase curves also differed between the two approaches; the post-processed cloud simulations predicted weaker day-night contrasts in emission and greater eastward shifts in the maximum emission compared to the active cloud modeling. This illustrates the importance of cloud radiative feedback and shows that post-processing will provide inaccurate solutions when clouds are thick enough to provide significant scattering.

astro-ph.EP↗

arXiv2018

A Framework for Prioritizing the TESS Planetary Candidates Most Amenable to Atmospheric Characterization

A key legacy of the recently launched TESS mission will be to provide the astronomical community with many of the best transiting exoplanet targets for atmospheric characterization. However, time is of the essence to take full advantage of this opportunity. JWST, although delayed, will still complete its nominal five year mission on a timeline that motivates rapid identification, confirmation, and mass measurement of the top atmospheric characterization targets from TESS. Beyond JWST, future dedicated missions for atmospheric studies such as ARIEL require the discovery and confirmation of several hundred additional sub-Jovian size planets (R_p < 10 R_Earth) orbiting bright stars, beyond those known today, to ensure a successful statistical census of exoplanet atmospheres. Ground-based ELTs will also contribute to surveying the atmospheres of the transiting planets discovered by TESS. Here we present a set of two straightforward analytic metrics, quantifying the expected signal-to-noise in transmission and thermal emission spectroscopy for a given planet, that will allow the top atmospheric characterization targets to be readily identified among the TESS planet candidates. Targets that meet our proposed threshold values for these metrics would be encouraged for rapid follow-up and confirmation via radial velocity mass measurements. Based on the catalog of simulated TESS detections by Sullivan et al. (2015), we determine appropriate cutoff values of the metrics, such that the TESS mission will ultimately yield a sample of $\sim300$ high-quality atmospheric characterization targets across a range of planet size bins, extending down to Earth-size, potentially habitable worlds.

astro-ph.EP↗

arXiv2018

The Transiting Exoplanet Community Early Release Science Program for JWST

The James Webb Space Telescope (JWST) presents the opportunity to transform our understanding of planets and the origins of life by revealing the atmospheric compositions, structures, and dynamics of transiting exoplanets in unprecedented detail. However, the high-precision, time-series observations required for such investigations have unique technical challenges, and prior experience with other facilities indicates that there will be a steep learning curve when JWST becomes operational. In this paper we describe the science objectives and detailed plans of the Transiting Exoplanet Community Early Release Science (ERS) Program, which is a recently approved program for JWST observations early in Cycle 1. The goal of this project, for which the obtained data will have no exclusive access period, is to accelerate the acquisition and diffusion of technical expertise for transiting exoplanet observations with JWST, while also providing a compelling set of representative datasets that will enable immediate scientific breakthroughs. The Transiting Exoplanet Community ERS Program will exercise the time-series modes of all four JWST instruments that have been identified as the consensus highest priorities, observe the full suite of transiting planet characterization geometries (transits, eclipses, and phase curves), and target planets with host stars that span an illustrative range of brightnesses. The observations in this program were defined through an inclusive and transparent process that had participation from JWST instrument experts and international leaders in transiting exoplanet studies. Community engagement in the project will be centered on a two-phase Data Challenge that culminates with the delivery of planetary spectra, time-series instrument performance reports, and open-source data analysis toolkits in time to inform the agenda for Cycle 2 of the JWST mission.

astro-ph.EP↗