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  • 1
    Online Resource
    Online Resource
    Implications of three-dimensional chemical transport in hot Jupiter atmospheres: Results from a consistently coupled chemistry-radiation-hydrodynamics model
    EDP Sciences ; 2020
    In:  Astronomy & Astrophysics Vol. 636 ( 2020-4), p. A68-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 636 ( 2020-4), p. A68-
    Abstract: We present results from a set of simulations using a fully coupled three-dimensional (3D) chemistry-radiation-hydrodynamics model and investigate the effect of transport of chemical species by the large-scale atmospheric flow in hot Jupiter atmospheres. We coupled a flexible chemical kinetics scheme to the Met Office Unified Model, which enables the study of the interaction of chemistry, radiative transfer, and fluid dynamics. We used a newly-released “reduced” chemical network, comprising 30 chemical species, that was specifically developed for its application in 3D atmosphere models. We simulated the atmospheres of the well-studied hot Jupiters HD 209458b and HD 189733b which both have dayside–nightside temperature contrasts of several hundred Kelvin and superrotating equatorial jets. We find qualitatively quite different chemical structures between the two planets, particularly for methane (CH 4 ), when advection of chemical species is included. Our results show that consideration of 3D chemical transport is vital in understanding the chemical composition of hot Jupiter atmospheres. Three-dimensional mixing leads to significant changes in the abundances of absorbing gas-phase species compared with what would be expected by assuming local chemical equilibrium, or from models including 1D – and even 2D – chemical mixing. We find that CH 4 , carbon dioxide (CO 2 ), and ammonia (NH 3 ) are particularly interesting as 3D mixing of these species leads to prominent signatures of out-of-equilibrium chemistry in the transmission and emission spectra, which are detectable with near-future instruments.
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/201937153
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2020
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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  • 2
    Online Resource
    Online Resource
    Early Release Science of the exoplanet WASP-39b with JWST NIRSpec G395H
    Springer Science and Business Media LLC ; 2023
    In:  Nature Vol. 614, No. 7949 ( 2023-02-23), p. 664-669
    Details
    In: Nature, Springer Science and Business Media LLC, Vol. 614, No. 7949 ( 2023-02-23), p. 664-669
    Abstract: Measuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking the formation and evolution of exoplanetary systems 1,2 . Access to the chemical inventory of an exoplanet requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based 3–5 and high-resolution ground-based 6–8 facilities. Here we report the medium-resolution ( R  ≈ 600) transmission spectrum of an exoplanet atmosphere between 3 and 5 μm covering several absorption features for the Saturn-mass exoplanet WASP-39b (ref.  9 ), obtained with the Near Infrared Spectrograph (NIRSpec) G395H grating of JWST. Our observations achieve 1.46 times photon precision, providing an average transit depth uncertainty of 221 ppm per spectroscopic bin, and present minimal impacts from systematic effects. We detect significant absorption from CO 2 (28.5 σ ) and H 2 O (21.5 σ ), and identify SO 2 as the source of absorption at 4.1 μm (4.8 σ ). Best-fit atmospheric models range between 3 and 10 times solar metallicity, with sub-solar to solar C/O ratios. These results, including the detection of SO 2 , underscore the importance of characterizing the chemistry in exoplanet atmospheres and showcase NIRSpec G395H as an excellent mode for time-series observations over this critical wavelength range 10 .
    Type of Medium: Online Resource
    ISSN: 0028-0836 , 1476-4687
    URL: Article
    DOI: 10.1038/s41586-022-05591-3
    RVK:
    TA 1000
    RVK:
    UA 1000
    RVK:
    WA 15000
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 120714-3
    detail.hit.zdb_id: 1413423-8
    SSG: 11
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  • 3
    Online Resource
    Online Resource
    Solar-to-supersolar sodium and oxygen absolute abundances for a ‘hot Saturn’ orbiting a metal-rich star
    Oxford University Press (OUP) ; 2022
    In:  Monthly Notices of the Royal Astronomical Society Vol. 515, No. 2 ( 2022-08-04), p. 3037-3058
    Details
    In: Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP), Vol. 515, No. 2 ( 2022-08-04), p. 3037-3058
    Abstract: We present new analysis of infrared transmission spectroscopy of the cloud-free hot-Saturn WASP-96b performed with the Hubble and Spitzer Space Telescopes (HST and Spitzer). The WASP-96b spectrum exhibits the absorption feature from water in excellent agreement with synthetic spectra computed assuming a cloud-free atmosphere. The HST-Spitzer spectrum is coupled with Very Large Telescope (VLT) optical transmission spectroscopy which reveals the full pressure-broadened profile of the sodium absorption feature and enables the derivation of absolute abundances. We confirm and correct for a spectral offset of $\Delta R_{{\rm p}}/R_{\ast }=(-4.29^{+0.31}_{-0.37})\, \times 10^{-3}$ of the VLT data relative to the HST-Spitzer spectrum. This offset can be explained by the assumed radius for the common-mode correction of the VLT spectra, which is a well-known feature of ground-based transmission spectroscopy. We find evidence for a lack of chromospheric and photometric activity of the host star which therefore make a negligible contribution to the offset. We measure abundances for Na and O that are consistent with solar to supersolar, with abundances relative to solar values of $21^{+27}_{-14}$ and $7^{+11}_{-4}$, respectively. We complement the transmission spectrum with new thermal emission constraints from Spitzer observations at 3.6 and 4.5 $\mu$m, which are best explained by the spectrum of an atmosphere with a temperature decreasing with altitude. A fit to the spectrum assuming an isothermal blackbody atmosphere constrains the dayside temperature to be Tp = 1545 ± 90 K.
    Type of Medium: Online Resource
    ISSN: 0035-8711 , 1365-2966
    URL: Article
    DOI: 10.1093/mnras/stac1530
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2022
    detail.hit.zdb_id: 2016084-7
    SSG: 16,12
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  • 4
    Online Resource
    Online Resource
    The TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI). II. Moist Cases—The Two Waterworlds
    American Astronomical Society ; 2022
    In:  The Planetary Science Journal Vol. 3, No. 9 ( 2022-09-01), p. 212-
    Details
    In: The Planetary Science Journal, American Astronomical Society, Vol. 3, No. 9 ( 2022-09-01), p. 212-
    Abstract: To identify promising exoplanets for atmospheric characterization and to make the best use of observational data, a thorough understanding of their atmospheres is needed. Three-dimensional general circulation models (GCMs) are one of the most comprehensive tools available for this task and will be used to interpret observations of temperate rocky exoplanets. Due to parameterization choices made in GCMs, they can produce different results, even for the same planet. Employing four widely used exoplanetary GCMs—ExoCAM, LMD-G, ROCKE-3D, and the UM—we continue the TRAPPIST-1 Habitable Atmosphere Intercomparison by modeling aquaplanet climates of TRAPPIST-1e with a moist atmosphere dominated by either nitrogen or carbon dioxide. Although the GCMs disagree on the details of the simulated regimes, they all predict a temperate climate with neither of the two cases pushed out of the habitable state. Nevertheless, the intermodel spread in the global mean surface temperature is nonnegligible: 14 K and 24 K in the nitrogen- and carbon dioxide-dominated case, respectively. We find substantial intermodel differences in moist variables, with the smallest amount of clouds in LMD-Generic and the largest in ROCKE-3D. ExoCAM predicts the warmest climate for both cases and thus has the highest water vapor content and the largest amount and variability of cloud condensate. The UM tends to produce colder conditions, especially in the nitrogen-dominated case due to a strong negative cloud radiative effect on the day side of TRAPPIST-1e. Our study highlights various biases of GCMs and emphasizes the importance of not relying solely on one model to understand exoplanet climates.
    Type of Medium: Online Resource
    ISSN: 2632-3338
    URL: Article
    DOI: 10.3847/PSJ/ac6cf2
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2022
    detail.hit.zdb_id: 3021068-9
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  • 5
    Online Resource
    Online Resource
    CAMEMBERT: A Mini-Neptunes General Circulation Model Intercomparison, Protocol Version 1.0.A CUISINES Model Intercomparison Project
    American Astronomical Society ; 2022
    In:  The Planetary Science Journal Vol. 3, No. 11 ( 2022-11-01), p. 261-
    Details
    In: The Planetary Science Journal, American Astronomical Society, Vol. 3, No. 11 ( 2022-11-01), p. 261-
    Abstract: With an increased focus on the observing and modeling of mini-Neptunes, there comes a need to better understand the tools we use to model their atmospheres. In this Paper, we present the protocol for the Comparing Atmospheric Models of Extrasolar Mini-Neptunes Building and Envisioning Retrievals and Transits, CAMEMBERT, project, an intercomparison of general circulation models (GCMs) used by the exoplanetary science community to simulate the atmospheres of mini-Neptunes. We focus on two targets well studied both observationally and theoretically with planned JWST cycle 1 observations: the warm GJ 1214b and the cooler K2-18b. For each target, we consider a temperature-forced case, a clear sky dual-gray radiative transfer case, and a clear sky multiband radiative transfer case, covering a range of complexities and configurations where we know differences exist between GCMs in the literature. This Paper presents all the details necessary to participate in the intercomparison, with the intention of presenting the results in future papers. Currently, there are eight GCMs participating ( ExoCAM , Exo-FMS , FMS PCM, Generic PCM , MITgcm , RM-GCM, THOR, and the Unified Model), and membership in the project remains open. Those interested in participating are invited to contact the authors.
    Type of Medium: Online Resource
    ISSN: 2632-3338
    URL: Article
    DOI: 10.3847/PSJ/ac9dfe
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2022
    detail.hit.zdb_id: 3021068-9
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  • 6
    Online Resource
    Online Resource
    Implications of different stellar spectra for the climate of tidally locked Earth-like exoplanets
    EDP Sciences ; 2020
    In:  Astronomy & Astrophysics Vol. 639 ( 2020-7), p. A99-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 639 ( 2020-7), p. A99-
    Abstract: The majority of detected potentially habitable exoplanets orbit stars cooler than the Sun and are therefore irradiated by a stellar spectrum that peaks at longer wavelengths than the spectrum incident on Earth. Here, we present results from a set of simulations of tidally locked terrestrial planets orbiting three different host stars to isolate the effect of the stellar spectra on the simulated climate. Specifically, we perform simulations based on TRAPPIST-1e, adopting an Earth-like atmosphere and using the UK Met Office Unified Model in an idealised ‘aqua-planet’ configuration. Whilst holding the planetary parameters constant, including the total stellar flux (900 W m −2 ) and orbital period (6.10 Earth days), we compare results between simulations where the stellar spectrum is that of a quiescent TRAPPIST-1, Proxima Centauri, and the Sun. In simulations with cooler host stars, an increased proportion of incident stellar radiation was absorbed directly by the troposphere compared to the surface. This in turn led to an increase in the stability against convection, that is, a reduction in overall cloud coverage on the dayside (reducing scattering), leading to warmer surface temperatures. The increased direct heating of the troposphere also led to more efficient heat transport from the dayside to the nightside and therefore to a reduced day-night temperature contrast. We inferred that planets with an Earth-like atmosphere orbiting cooler stars had lower dayside cloud coverage, potentially allowing habitable conditions at increased orbital radii, compared to similar planets orbiting hotter stars for a given planetary rotation rate.
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/202038089
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2020
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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  • 7
    Online Resource
    Online Resource
    TRAPPIST Habitable Atmosphere Intercomparison (THAI) Workshop Report
    American Astronomical Society ; 2021
    In:  The Planetary Science Journal Vol. 2, No. 3 ( 2021-06-01), p. 106-
    Details
    In: The Planetary Science Journal, American Astronomical Society, Vol. 2, No. 3 ( 2021-06-01), p. 106-
    Abstract: The era of atmospheric characterization of terrestrial exoplanets is just around the corner. Modeling prior to observations is crucial in order to predict the observational challenges and to prepare for the data interpretation. This paper presents the report of the TRAPPIST Habitable Atmosphere Intercomparison workshop (2020 September 14–16). A review of the climate models and parameterizations of the atmospheric processes on terrestrial exoplanets, model advancements, and limitations, as well as direction for future model development, was discussed. We hope that this report will be used as a roadmap for future numerical simulations of exoplanet atmospheres and maintaining strong connections to the astronomical community.
    Type of Medium: Online Resource
    ISSN: 2632-3338
    URL: Article
    DOI: 10.3847/PSJ/abf4df
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2021
    detail.hit.zdb_id: 3021068-9
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  • 8
    Online Resource
    Online Resource
    The TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI). I. Dry Cases—The Fellowship of the GCMs
    American Astronomical Society ; 2022
    In:  The Planetary Science Journal Vol. 3, No. 9 ( 2022-09-01), p. 211-
    Details
    In: The Planetary Science Journal, American Astronomical Society, Vol. 3, No. 9 ( 2022-09-01), p. 211-
    Abstract: With the commissioning of powerful, new-generation telescopes such as the James Webb Space Telescope (JWST) and the ground-based Extremely Large Telescopes, the first characterization of a high molecular weight atmosphere around a temperate rocky exoplanet is imminent. Atmospheric simulations and synthetic observables of target exoplanets are essential to prepare and interpret these observations. Here we report the results of the first part of the TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI) project, which compares 3D numerical simulations performed with four state-of-the-art global climate models (ExoCAM, LMD-Generic, ROCKE-3D, Unified Model) for the potentially habitable target TRAPPIST-1e. In this first part, we present the results of dry atmospheric simulations. These simulations serve as a benchmark to test how radiative transfer, subgrid-scale mixing (dry turbulence and convection), and large-scale dynamics impact the climate of TRAPPIST-1e and consequently the transit spectroscopy signature as seen by JWST. To first order, the four models give results in good agreement. The intermodel spread in the global mean surface temperature amounts to 7 K (6 K) for the N 2 -dominated (CO 2 -dominated) atmosphere. The radiative fluxes are also remarkably similar (intermodel variations less than 5%), from the surface (1 bar) up to atmospheric pressures ∼5 mbar. Moderate differences between the models appear in the atmospheric circulation pattern (winds) and the (stratospheric) thermal structure. These differences arise between the models from (1) large-scale dynamics, because TRAPPIST-1e lies at the tipping point between two different circulation regimes (fast and Rhines rotators) in which the models can be alternatively trapped, and (2) parameterizations used in the upper atmosphere such as numerical damping.
    Type of Medium: Online Resource
    ISSN: 2632-3338
    URL: Article
    DOI: 10.3847/PSJ/ac6cf0
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2022
    detail.hit.zdb_id: 3021068-9
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  • 9
    Online Resource
    Online Resource
    TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI): motivations and protocol version 1.0
    Copernicus GmbH ; 2020
    In:  Geoscientific Model Development Vol. 13, No. 2 ( 2020-02-21), p. 707-716
    Details
    In: Geoscientific Model Development, Copernicus GmbH, Vol. 13, No. 2 ( 2020-02-21), p. 707-716
    Abstract: Abstract. Upcoming telescopes such as the James Webb Space Telescope (JWST), the European Extremely Large Telescope (E-ELT), the Thirty Meter Telescope (TMT) or the Giant Magellan Telescope (GMT) may soon be able to characterize, through transmission, emission or reflection spectroscopy, the atmospheres of rocky exoplanets orbiting nearby M dwarfs. One of the most promising candidates is the late M-dwarf system TRAPPIST-1, which has seven known transiting planets for which transit timing variation (TTV) measurements suggest that they are terrestrial in nature, with a possible enrichment in volatiles. Among these seven planets, TRAPPIST-1e seems to be the most promising candidate to have habitable surface conditions, receiving ∼66 % of the Earth's incident radiation and thus needing only modest greenhouse gas inventories to raise surface temperatures to allow surface liquid water to exist. TRAPPIST-1e is, therefore, one of the prime targets for the JWST atmospheric characterization. In this context, the modeling of its potential atmosphere is an essential step prior to observation. Global climate models (GCMs) offer the most detailed way to simulate planetary atmospheres. However, intrinsic differences exist between GCMs which can lead to different climate prediction and thus observability of gas and/or cloud features in transmission and thermal emission spectra. Such differences should preferably be known prior to observations. In this paper we present a protocol to intercompare planetary GCMs. Four testing cases are considered for TRAPPIST-1e, but the methodology is applicable to other rocky exoplanets in the habitable zone. The four test cases included two land planets composed of modern-Earth and pure-CO2 atmospheres and two aqua planets with the same atmospheric compositions. Currently, there are four participating models (LMDG, ROCKE-3D, ExoCAM, UM); however, this protocol is intended to let other teams participate as well.
    Type of Medium: Online Resource
    ISSN: 1991-9603
    URL: Article
    DOI: 10.5194/gmd-13-707-2020
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2020
    detail.hit.zdb_id: 2456725-5
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  • 10
    Online Resource
    Online Resource
    Coordinating systems of care using health information technology: development of the ADHD Care Assistant
    Informa UK Limited ; 2016
    In:  Advances in School Mental Health Promotion Vol. 9, No. 3-4 ( 2016-10), p. 201-218
    Details
    In: Advances in School Mental Health Promotion, Informa UK Limited, Vol. 9, No. 3-4 ( 2016-10), p. 201-218
    Type of Medium: Online Resource
    ISSN: 1754-730X , 2049-8535
    URL: Article
    DOI: 10.1080/1754730X.2016.1199283
    Language: English
    Publisher: Informa UK Limited
    Publication Date: 2016
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