Eureka!: An End-to-End Pipeline for JWST Time-Series
Observations

Bell, Taylor; Ahrer, Eva-Maria; Brande, Jonathan; Carter, Aarynn L.; Feinstein, Adina D.; Caloca, Giannina Guzman; Mansfield, Megan; Zieba, Sebastian; Piaulet, Caroline; Benneke, Björn; Filippazzo, Joseph; May, Erin M.; Roy, Pierre-Alexis; Kreidberg, Laura; Stevenson, Kevin B.

doi:10.21105/joss.04503

Cited by 50 publications

(54 citation statements)

References 18 publications

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“…We use the Eureka! pipeline 47 for the data reduction steps of detector processing, data calibration and stellar spectrum extraction, and the ExoTEP pipeline 48 – 50 to generate light curves in each wavelength bin and perform light curve fitting.…”

Section: Methodsmentioning

confidence: 99%

“…The codes used in this publication to extract, reduce, and analyse the data are as follows; STScI JWST Calibration pipeline ( https://github.com/spacetelescope/jwst ), FIREFLy 23 , tshirt 40 , Eureka! 47 ( https://eurekadocs.readthedocs.io/en/latest/ ) and Tiberius 16 , 52 , 53 . In addition, these made use of Exoplanet 43 ( https://docs.exoplanet.codes/en/latest/ ), Pymc3 (ref.…”

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confidence: 99%

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Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM

Rustamkulov

Sing

Mukherjee

et al. 2023

Nature

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134

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Transmission spectroscopy 1,2,3 of exoplanets has revealed signatures of water vapor, aerosols, and alkali metals in a few dozen exoplanet atmospheres 4,5 . However, these previous inferences with the Hubble and Spitzer Space Telescopes were hindered by the observations' relatively narrow wavelength range and spectral resolving power, which precluded the unambiguous identification of other chemical species -in particular the primary carbon-bearing molecules 6,7 . Here we report a broad-wavelength 0.5-5.5 µm atmospheric transmission spectrum of WASP39 b 8 , a 1200 K, roughly Saturn-mass, Jupiter-radius exoplanet, measured with JWST NIRSpec's PRISM mode 9 as part of the JWST Transiting Exoplanet Community Early Release Science Team program 10,11,12 . We robustly detect multiple chemical species at high significance, including Na (19σ), H 2 O (33σ), CO 2 (28σ), and CO (7σ). The non-detection of CH 4 , combined with a strong CO 2 feature, favours atmospheric models with a super-solar atmospheric metallicity. An unanticipated absorption feature at 4µm is best explained by SO 2 (2.7σ), which could be a tracer of atmospheric photochemistry. These observations demonstrate JWST's sensitivity to a rich diversity of exoplanet compositions and chemical processes.We observed one transit of WASP-39b on 10 July 2022 with JWST's Near InfraRed Spectrograph (NIRSpec) 9,13 , using the PRISM mode, as part of the JWST Transiting Exoplanet Community Early Release Science Program (ERS Program 1366) (PIs: N. Batalha, J. Bean, K. Stevenson) 10,11 . These observations cover the 0.5-5.5µm wavelength range at a native resolving power of R = λ/∆λ ∼ 20-300. WASP-39b was selected for this JWST ERS Program due to previous space-and ground-based observations revealing strong alkali metal absorption and multiple prominent H 2 O bands 4,6,14,15,16 , suggesting strong signal-to-noise could be obtained with JWST. However, the limited wavelength range of existing transmission spectra (0.3-1.65µm, combined with two wide photometric Spitzer channels at 3.6 and 4.5µm) left several important questions unresolved. Previous estimates of WASP-39b's atmospheric metallicity-a measure of the relative abundance of all gases heavier than hydrogen or helium-vary by four orders of magnitude 6,16,17,18,19,20 . Accurate determinations of metallicity can elucidate formation pathways and provide greater insight into the planet's history 21 . The JWST NIRSpec PRISM observations we present here offer a more detailed view into WASP-39b's atmospheric composition than has previously been possible (see ref. 21 for an initial infrared analysis of this data).We obtained time-series spectroscopy over 8.23 hours centered around the transit event to extract the wavelength-dependent absorption by the planet's atmosphere-i.e., the transmission spectrum, which probes the planet's day-night terminator region near millibar pressures. We used NIRSpec PRISM in Bright Object Time Series (BOTS) mode. WASP-39 is a bright, nearby, relatively inactive 23 G7 type star with an effective tempe...

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM

Rustamkulov

Sing

Mukherjee

et al. 2023

Nature

Self Cite

134

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“…Eureka! is an open-source pipeline designed to perform spectral extraction and fitting for JWST exoplanet time-series observations 55 . The Eureka!…”

Section: Methodsmentioning

confidence: 99%

“…The codes used in this publication to extract, reduce and analyse the data are as follows: batman 99 , emcee 60 , Eureka! 55 , jwst 100 , chromatic, chromatic-fitting, PyMC3 61 , Exoplanet 62 , 63 , gCMCRT 101 , CONAN 57 , 58 , ExoTiC-LD 64 – 66 , LACOSMIC 59 , PICASO 77 , 78 , Virga 90 and VULCAN 33 . The Jupyter notebook to reproduce the transmission spectrum as shown here using the Eureka!…”

mentioning

confidence: 99%

Early Release Science of the exoplanet WASP-39b with JWST NIRCam

Ahrer

Stevenson

Mansfield

et al. 2023

Nature

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Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet atmospheres is a fundamental step towards constraining the dominant chemical processes at work and, if in equilibrium, revealing planet formation histories. Transmission spectroscopy (for example, refs. 1,2) provides the necessary means by constraining the abundances of oxygen- and carbon-bearing species; however, this requires broad wavelength coverage, moderate spectral resolution and high precision, which, together, are not achievable with previous observatories. Now that JWST has commenced science operations, we are able to observe exoplanets at previously uncharted wavelengths and spectral resolutions. Here we report time-series observations of the transiting exoplanet WASP-39b using JWST’s Near InfraRed Camera (NIRCam). The long-wavelength spectroscopic and short-wavelength photometric light curves span 2.0–4.0 micrometres, exhibit minimal systematics and reveal well defined molecular absorption features in the planet’s spectrum. Specifically, we detect gaseous water in the atmosphere and place an upper limit on the abundance of methane. The otherwise prominent carbon dioxide feature at 2.8 micrometres is largely masked by water. The best-fit chemical equilibrium models favour an atmospheric metallicity of 1–100-times solar (that is, an enrichment of elements heavier than helium relative to the Sun) and a substellar C/O ratio. The inferred high metallicity and low C/O ratio may indicate significant accretion of solid materials during planet formation (for example, refs. 3,4,) or disequilibrium processes in the upper atmosphere (for example, refs. 5,6).

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“…We reduced the data using three separate pipelines: Eureka! (Bell et al 2022), FIREFLy (Rustamkulov et al 2022(Rustamkulov et al , 2023, and Tiberius (Kirk et al 2018(Kirk et al , 2019(Kirk et al , 2021. Each pipeline analysis is described below.…”

Section: Nirspec G395h Data Reductionmentioning

confidence: 99%

High Tide or Riptide on the Cosmic Shoreline? A Water-rich Atmosphere or Stellar Contamination for the Warm Super-Earth GJ 486b from JWST Observations

Moran

Stevenson

Sing

et al. 2023

ApJL

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Planets orbiting M-dwarf stars are prime targets in the search for rocky exoplanet atmospheres. The small size of M dwarfs renders their planets exceptional targets for transmission spectroscopy, facilitating atmospheric characterization. However, it remains unknown whether their host stars’ highly variable extreme-UV radiation environments allow atmospheres to persist. With JWST, we have begun to determine whether or not the most favorable rocky worlds orbiting M dwarfs have detectable atmospheres. Here, we present a 2.8–5.2 μm JWST NIRSpec/G395H transmission spectrum of the warm (700 K, 40.3× Earth’s insolation) super-Earth GJ 486b (1.3 R ⊕ and 3.0 M ⊕). The measured spectrum from our two transits of GJ 486b deviates from a flat line at 2.2σ − 3.3σ, based on three independent reductions. Through a combination of forward and retrieval models, we determine that GJ 486b either has a water-rich atmosphere (with the most stringent constraint on the retrieved water abundance of H2O > 10% to 2σ) or the transmission spectrum is contaminated by water present in cool unocculted starspots. We also find that the measured stellar spectrum is best fit by a stellar model with cool starspots and hot faculae. While both retrieval scenarios provide equal quality fits ( χ ν 2 = 1.0 ) to our NIRSpec/G395H observations, shorter wavelength observations can break this degeneracy and reveal if GJ 486b sustains a water-rich atmosphere.

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Eureka!: An End-to-End Pipeline for JWST Time-Series Observations

Cited by 50 publications

References 18 publications

Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM

Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM

Early Release Science of the exoplanet WASP-39b with JWST NIRCam

High Tide or Riptide on the Cosmic Shoreline? A Water-rich Atmosphere or Stellar Contamination for the Warm Super-Earth GJ 486b from JWST Observations

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