Chemical variation with altitude and longitude on exo-Neptunes: Predictions for Ariel phase-curve observations

Moses, J. I.; Tremblin, Pascal; Venot, Olivia; Miguel, Yamila

doi:10.1007/s10686-021-09749-1

Cited by 35 publications

(49 citation statements)

References 156 publications

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“…Fig. 2 Relative phase curve amplitude in AIRS-CH1 (3.9-7.8 micron) as a function of metallicity and effective temperature from a grid of 2D ATMO models [57]. Simulations performed with the radius, rotation and stellar type of GJ436b.…”

Section: Sq5: How Do Thermal Structure and Aerosols Vary In Time?mentioning

confidence: 99%

A survey of exoplanet phase curves with Ariel

Charnay,

Mendonça,

Kreidberg

et al. 2021

Preprint

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The ESA-Ariel mission will include a tier dedicated to exoplanet phase curves corresponding to ∼10% of the science time. We present here the current observing strategy for studying exoplanet phase curves with Ariel. We define science questions, requirements and a list of potential targets. We also estimate the precision of phase curve reconstruction and atmospheric retrieval using simulated phase curves. Based on this work, we found that full-orbit phase variations for 35-40 exoplanets could be observed during the 3.5-yr mission. This statistical sample would provide key constraints on atmospheric dynamics, composition, thermal structure and clouds of warm exoplanets, complementary to the scientific yield from spectroscopic transits/eclipses measurements.

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Section: Sq5: How Do Thermal Structure and Aerosols Vary In Time?mentioning

confidence: 99%

A survey of exoplanet phase curves with Ariel

Charnay,

Mendonça,

Kreidberg

et al. 2021

Preprint

Self Cite

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“…The field of exoplanet research is now entering the stage of probing the spatial distribution of atmospheric composition (Venot et al 2018;Ehrenreich et al 2020). Upcoming observatories, such as the James Webb Space Telescope (Venot et al 2020a;Drummond et al 2020) and the Atmospheric Remote-sensing Infrared Exoplanet Large-survey (Moses et al 2022;Tinetti et al 2021), will have the ability to provide accurate spectral data and map out the compositional variation across the globe of the planet. Chemical kinetics models (e.g., Kasting et al 1979;Yung et al 1984;Moses et al 2011;Venot et al 2012;Hu et al 2012;Miguel & Kaltenegger 2014;Molaverdikhani et al 2019;Hobbs et al 2019;Tsai et al 2021a) have played an instrumental role in understanding the fundamental processes that shape the atmospheric compositions.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, retrieval works (Taylor et al 2020;Feng et al 2020;Irwin et al 2020;Pluriel et al 2020Pluriel et al , 2022 have shown that atmospheric retrievals can suffer biases when neglecting the 3D nature of the planets. Pseudo-2D models that employ a rotating 1D column have started to emerge (Agúndez et al 2014;Venot et al 2020b;Baeyens et al 2021;Moses et al 2022;Roth et al 2021) and have significantly improved 1D models by including horizontal interconnection; however, the circulation is considerably simplified, with a globally uniform jet and the chemical-radiative feedback excluded. In order to study their interactions in depth and to be in position for the prospective observations, a self-consistent 3D general circulation model (GCM) that couples chemistry, radiation, and circulation is desired.…”

Section: Introductionmentioning

confidence: 99%

A mini-chemical scheme with net reactions for 3D general circulation models

Tsai

Lee

Pierrehumbert

2022

A&A

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Context. Growing evidence has indicated that the global composition distribution plays an indisputable role in interpreting observational data. Three-dimensional general circulation models (GCMs) with a reliable treatment of chemistry and clouds are particularly crucial in preparing for upcoming observations. In attempts to achieve 3D chemistry-climate modeling, the challenge mainly lies in the expensive computing power required for treating a large number of chemical species and reactions. Aims. Motivated by the need for a robust and computationally efficient chemical scheme, we devise a mini-chemical network with a minimal number of species and reactions for H2-dominated atmospheres. Methods. We apply a novel technique to simplify the chemical network from a full kinetics model, VULCAN, by replacing a large number of intermediate reactions with net reactions. The number of chemical species is cut down from 67 to 12, with the major species of thermal and observational importance retained, including H2O, CH4, CO, CO2, C2H2, NH3, and HCN. The size of the total reactions is also greatly reduced, from ~800 to 20. We validated the mini-chemical scheme by verifying the temporal evolution and benchmarking the predicted compositions in four exoplanet atmospheres (GJ 1214b, GJ 436b, HD 189733b, and HD 209458b) against the full kinetics of VULCAN. Results. The mini-network reproduces the chemical timescales and composition distributions of the full kinetics well within an order of magnitude for the major species in the pressure range of 1 bar–0.1 mbar across various metallicities and carbon-to-oxygen (C/O) ratios. Conclusions. We have developed and validated a mini-chemical scheme using net reactions to significantly simplify a large chemical network. The small scale of the mini-chemical scheme permits simple use and fast computation, which is optimal for implementation in a 3D GCM or a retrieval framework. We focus on the thermochemical kinetics of net reactions in this paper and address photochemistry in a follow-up paper.

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“…The field of exoplanet research is now entering the stage of probing the spatial distribution of atmospheric composition (Venot et al 2018;Ehrenreich et al 2020). The upcoming observatories, such as the James Webb Space Telescope (JWST; Venot et al (2020); Drummond et al (2020)) and the Atmospheric Remotesensing Infrared Exoplanet Large-survey (Ariel; (Moses et al 2021;Tinetti et al 2021)), will have the ability to provide accurate spectral data and map out the compositional variation across the globe of the planet. Chemical kinetics models (e.g., Kasting et al 1979;Yung et al 1984;Moses et al 2011;Venot et al 2012;Hu et al 2012;Miguel & Kaltenegger 2014;Molaverdikhani et al 2019;Hobbs et al 2019;Tsai et al 2021) have played an instrumental role in understanding the fundamental processes that shape the atmospheric compositions.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, retrieval works (Taylor et al 2020;Feng et al 2020;Irwin et al 2020;Pluriel et al 2020;Pluriel, William et al 2022) have shown that atmospheric retrievals can suffer biases when neglecting the 3D nature of the planets. Pseudo-2D models employing a rotating 1D-column have started to emerge (Agúndez et al 2014;Venot et al 2020b;Baeyens et al 2021;Moses et al 2021;Roth & Parmentier 2021) and significantly improved the lack of horizontal interconnection in 1D models, but the circulation is considerably simplified with a globally uniform jet and the chemical-radiative feedback is excluded. A self-consistent 3D GCM coupling chemistry, radiation, and circulation is desired to study their interactions in depth and to be in position for the prospective observations.…”

Section: Introductionmentioning

confidence: 99%

A Mini-Chemical Scheme with Net Reactions for 3D GCMs I.: Thermochemical Kinetics

Tsai,

Lee,

Pierrehumbert

2022

Preprint

View full text Add to dashboard Cite

Context. Growing evidence has indicated that the global composition distribution plays an indisputable role in interpreting observational data. 3D general circulation models (GCMs) with a reliable treatment of chemistry and clouds are particularly crucial in preparing for the upcoming observations. In the effort of achieving 3D chemistry-climate modeling, the challenge mainly lies in the expensive computing power required for treating a large number of chemical species and reactions. Aims. Motivated by the need for a robust and computationally efficient chemical scheme, we devise a mini-chemical network with a minimal number of species and reactions for H 2 -dominated atmospheres. Methods. We apply a novel technique to simplify the chemical network from a full kinetics model -VULCAN by replacing a large number of intermediate reactions with net reactions. The number of chemical species is cut down from 67 to 12, with the major species of thermal and observational importance retained, including H 2 O, CH 4 , CO, CO 2 , C 2 H 2 , NH 3 , and HCN. The size of the total reactions is greatly reduced from ∼ 800 to 20. The mini-chemical scheme is validated by verifying the temporal evolution and benchmarking the predicted compositions in four exoplanet atmospheres (GJ 1214b, GJ 436b, HD 189733b, HD 209458b) against the full kinetics of VULCAN.Results. The mini-network reproduces the chemical timescales and composition distributions of the full kinetics well within an order of magnitude for the major species in the pressure range of 1 bar -0.1 mbar across various metallicities and carbon-to-oxygen (C/O) ratios. Conclusions. We have developed and validated a mini-chemical scheme using net reactions to significantly simplify a large chemical network. The small scale of the mini-chemical scheme permits simple use and fast computation, which is optimal for implementation in a 3D GCM or a retrieval framework. We focus on the thermochemical kinetics of net reactions in this paper and address photochemistry in a follow-up paper.

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Chemical variation with altitude and longitude on exo-Neptunes: Predictions for Ariel phase-curve observations

Cited by 35 publications

References 156 publications

A survey of exoplanet phase curves with Ariel

A survey of exoplanet phase curves with Ariel

A mini-chemical scheme with net reactions for 3D general circulation models

A Mini-Chemical Scheme with Net Reactions for 3D GCMs I.: Thermochemical Kinetics

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