The ExoMol Atlas of Molecular Opacities

Tennyson, Jonathan; Yurchenko, Sergei N.

doi:10.3390/atoms6020026

Cited by 68 publications

(45 citation statements)

References 201 publications

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“…Similar to the equilibrium model, we also included a grey cloud and assumed an isothermal temperature profile. The free-retrieval results in a better fit, with a BIC of 60.75 for the same number of data points and free parameters, as it fills in the 1.2 µm HST opacity, where we would expect to see a larger dip at ∼1 µm if water were the only absorber at these wavelengths (Figure 14, (Tennyson & Yurchenko 2018)). With the opacity of FeH at ∼1µm, this model better accommodates the slope of the water feature at ∼1.6 µm as well as the diminishing opacity in the bluer wavelengths.…”

Section: Transmission Spectra Retrieval Analysismentioning

confidence: 91%

Transmission Spectroscopy of WASP-79b from 0.6 to 5.0 μm

Sotzen

Stevenson

Sing

et al. 2019

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As part of the PanCET program, we have conducted a spectroscopic study of WASP-79b, an inflated hot Jupiter orbiting an F-type star in Eridanus with a period of 3.66 days. Building on the original WASP and TRAPPIST photometry of Smalley et al. (2012), we examine HST/WFC3 (1.125 -1.650 µm), Magellan/LDSS-3C (0.6 -1 µm) data, and Spitzer data (3.6 and 4.5 µm). Using data from all three instruments, we constrain the water abundance to be -2.20 ≤ log(H 2 O) ≤ -1.55. We present these results along with the results of an atmospheric retrieval analysis, which favor inclusion of FeH and Hin the atmospheric model. We also provide an updated ephemeris based on the Smalley, HST/WFC3, LDSS-3C, Spitzer, and TESS transit times. With the detectable water feature and its occupation of the clear/cloudy transition region of the temperature/gravity phase space, WASP-79b is a target of interest for the approved JWST Director's Discretionary Early Release Science (DD ERS) program, with ERS observations planned to be the first to execute in Cycle 1. Transiting exoplanets have been approved for 78.1 hours of data collection, and with the delay in the JWST launch, WASP-79b is now a target for the Panchromatic Transmission program. This program will observe WASP-79b for 42 hours in 4 different instrument modes, providing substantially more data by which to investigate this hot Jupiter.

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Section: Transmission Spectra Retrieval Analysismentioning

confidence: 91%

Transmission Spectroscopy of WASP-79b from 0.6 to 5.0 μm

Sotzen

Stevenson

Sing

et al. 2019

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“…The second major improvement concerns the line lists used for important molecular opacity sources such as CH 4 and NH 3 used in the model atmospheres. These line lists are taken primarily from the ExoMol group (Tennyson & Yurchenko 2018), and include significantly more transitions required to accurately model the high-temperature atmospheres of brown dwarfs and giant exoplanets. These more complete line lists have added opacity to the 1D model atmosphere, changing the predicted emission spectra (Figures 15 and 16) and leading to warmer temperature structures (Figure 4).…”

Section: Evolutionary Tracksmentioning

confidence: 99%

A new set of atmosphere and evolution models for cool T–Y brown dwarfs and giant exoplanets

Phillips

Tremblin

Baraffe

et al. 2020

A&A

218

262

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We present a new set of solar metallicity atmosphere and evolutionary models for very cool brown dwarfs and self-luminous giant exoplanets, which we term ATMO 2020. Atmosphere models are generated with our state-of-the-art 1D radiative-convective equilibrium code ATMO, and are used as surface boundary conditions to calculate the interior structure and evolution of 0.001 − 0.075 M objects. Our models include several key improvements to the input physics used in previous models available in the literature. Most notably, the use of a new H-He equation of state including ab initio quantum molecular dynamics calculations has raised the mass by ∼ 1 − 2% at the stellar-substellar boundary and has altered the cooling tracks around the hydrogen and deuterium burning minimum masses. A second key improvement concerns updated molecular opacities in our atmosphere model ATMO, which now contains significantly more line transitions required to accurately capture the opacity in these hot atmospheres. This leads to warmer atmospheric temperature structures, further changing the cooling curves and predicted emission spectra of substellar objects. We present significant improvement for the treatment of the collisionally broadened potassium resonance doublet, and highlight the importance of these lines in shaping the red-optical and near-infrared spectrum of brown dwarfs. We generate three different grids of model simulations, one using equilibrium chemistry and two using non-equilibrium chemistry due to vertical mixing, all three computed self-consistently with the pressure-temperature structure of the atmosphere. We show the impact of vertical mixing on emission spectra and in colourmagnitude diagrams, highlighting how the 3.5 − 5.5 µm flux window can be used to calibrate vertical mixing in cool T-Y spectral type objects.

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“…PLATON is based on ExoTransmit (M-R Kempton et al 2017) and uses a fast Python based algorithm to compute forward models for planetary atmospheres, which are then compared with the data in a retrieval framework. PLATON includes opacities for 30 different molecular and atomic species (Zhang et al 2019b), the majority of which are calculated using line lists from ExoMol (Tennyson et al 2018) and HITRAN (Gordon et al 2017). We use nested sampling for our retrievals to accurately capture the posteriors of atmospheric model parameters that may display multi-modality.…”

Section: Atmospheric Retrieval: Platonmentioning

confidence: 99%

A Hubble PanCET Study of HAT-P-11b: A Cloudy Neptune with a Low Atmospheric Metallicity

Chachan

Knutson

Gao

et al. 2019

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We present the first comprehensive look at the 0.35−5 µm transmission spectrum of the warm (∼ 800 K) Neptune HAT-P-11b derived from thirteen individual transits observed using the Hubble and Spitzer Space Telescopes. Along with the previously published molecular absorption feature in the 1.1−1.7 µm bandpass, we detect a distinct absorption feature at 1.15 µm and a weak feature at 0.95 µm, indicating the presence of water and/or methane with a combined significance of 4.4 σ. We find that this planet's nearly flat optical transmission spectrum and attenuated near-infrared molecular absorption features are best-matched by models incorporating a high-altitude cloud layer. Atmospheric retrievals using the combined 0.35−1.7 µm HST transmission spectrum yield strong constraints on atmospheric cloudtop pressure and metallicity, but we are unable to match the relatively shallow Spitzer transit depths without under-predicting the strength of the near-infrared molecular absorption bands. HAT-P-11b's HST transmission spectrum is well-matched by predictions from our microphysical cloud models. Both forward models and retrievals indicate that HAT-P-11b most likely has a relatively low atmospheric metallicity (< 4.6 Z and < 86 Z at the 2σ and 3σ levels respectively), in contrast to the expected trend based on the solar system planets. Our work also demonstrates that the wide wavelength coverage provided by the addition of the HST STIS data is critical for making these inferences.

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The ExoMol Atlas of Molecular Opacities

Cited by 68 publications

References 201 publications

Transmission Spectroscopy of WASP-79b from 0.6 to 5.0 μm

Transmission Spectroscopy of WASP-79b from 0.6 to 5.0 μm

A new set of atmosphere and evolution models for cool T–Y brown dwarfs and giant exoplanets

A Hubble PanCET Study of HAT-P-11b: A Cloudy Neptune with a Low Atmospheric Metallicity

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