A5108167191- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Atmospheric Ozone and Climate
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Spectroscopy and Laser Applications
- Planetary Science and Exploration
- Advanced Chemical Physics Studies
- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Isotope Analysis in Ecology
- Solar and Space Plasma Dynamics
- Aeolian processes and effects
- Spacecraft and Cryogenic Technologies
- Space Exploration and Technology
- Molecular Spectroscopy and Structure
- Geophysics and Gravity Measurements
- Astronomical Observations and Instrumentation
- History and advancements in chemistry
- Astronomical and nuclear sciences
- High-pressure geophysics and materials
- Marine and coastal ecosystems
- Mass Spectrometry Techniques and Applications
- Paleontology and Stratigraphy of Fossils
- Chemical Thermodynamics and Molecular Structure
University of Exeter
2016-2024
Institut de Recherche en Astrophysique et Planétologie
2014-2023
Goddard Space Flight Center
2015-2018
York University
2016-2017
Oak Ridge Associated Universities
2015-2017
Université de Toulouse
2014-2016
Université Toulouse III - Paul Sabatier
2014-2016
Centre National de la Recherche Scientifique
2005-2015
Université de Bordeaux
2009-2015
Université de Lorraine
2013-2015
We present a novel chemical database for gas-phase astrochemistry. Named the KInetic Database Astrochemistry (KIDA), this consists of reactions with rate coefficients and uncertainties that will be vetted to greatest extent possible. Submissions measured calculated are welcome, studied by experts before inclusion into database. Besides providing kinetic information interstellar medium, KIDA is planned contain such data planetary atmospheres circumstellar envelopes. Each year, subset in...
We present a new set of solar metallicity atmosphere and evolutionary models for very cool brown dwarfs self-luminous giant exoplanets, which we term ATMO 2020. Atmosphere are generated with our state-of-the-art 1D radiative-convective equilibrium code ATMO, used as surface boundary conditions to calculate the interior structure evolution $0.001-0.075\,\mathrm{M_{\odot}}$ objects. Our include several key improvements input physics in previous available literature. Most notably, use H-He...
Photochemistry is a fundamental process of planetary atmospheres that regulates the atmospheric composition and stability. However, no unambiguous photochemical products have been detected in exoplanet to date. Recent observations from JWST Transiting Exoplanet Early Release Science Program found spectral absorption feature at 4.05 $\mu$m arising SO$_2$ atmosphere WASP-39b. WASP-39b 1.27-Jupiter-radii, Saturn-mass (0.28 M$_J$) gas giant orbiting Sun-like star with an equilibrium temperature...
Our purpose is to release a chemical network, and the associated rate coefficients, developed for temperature pressure range relevant hot Jupiters atmospheres. Using this we study vertical atmospheric composition of two (HD209458b, HD189733b) with model that includes photolyses mixing produce synthetic spectra. The scheme derived from applied combustion models have been methodically validated over temperatures pressures typical layers influencing observations Jupiters. We compare predictions...
Recognizing whether a planet can support life is primary goal of future exoplanet spectral characterization missions, but past research on habitability assessment has largely ignored the vastly different conditions that have existed in our planet's long habitable history. This study presents simulations yet dramatically phase Earth's history, when atmosphere contained Titan-like organic-rich haze. Prior work claimed haze-rich Archean Earth (3.8-2.5 billion years ago) would be frozen due to...
We report the results of an extended spectropolarimetric and photometric monitoring weak-line T Tauri star TAP 26, carried out within MaTYSSE programme with ESPaDOnS spectropolarimeter at 3.6 m Canada-France-Hawaii Telescope. Applying Zeeman-Doppler Imaging to our observations, concentrating in 2015 November 2016 January spanning 72 d total, 16 13 January, we reconstruct surface brightness magnetic field maps for both epochs demonstrate that distributions exhibit temporal evolution not...
We present a grid of forward model transmission spectra, adopting an isothermal temperature-pressure profile, alongside corresponding equilibrium chemical abundances for 117 observationally significant hot exoplanets (equilibrium temperatures 547–2710 K). This has been developed using 1D radiative–convective–chemical termed ATMO, with up-to-date high-temperature opacities. interpretation observations 10 exoplanets, including best-fitting parameters and χ2 maps. In agreement previous works,...
We present results from a set of simulations using fully coupled three-dimensional (3D) chemistry-radiation-hydrodynamics model and investigate the effect transport chemical species by large-scale atmospheric flow in hot Jupiter atmospheres. couple flexible kinetics scheme to Met Office Unified Model which enables study interaction chemistry, radiative transfer fluid dynamics. use newly-released "reduced" network comprising 30 that has been specifically developed for application 3D...
We present the discovery of four new transiting hot jupiters, detected mainly from SuperWASP-North and SOPHIE observations. These planets, WASP-52b, WASP-58b, WASP-59b, WASP-60b, have orbital periods ranging 1.7 to 7.9 days, masses between 0.46 0.94 M_Jup, radii 0.73 1.49 R_Jup. Their G1 K5 dwarf host stars V magnitudes in range 11.7-13.0. The depths transits are 0.6 2.7%, depending on target. With their large radii, WASP-52b 58b cases low-density, inflated whereas WASP-59b is likely a...
Future NASA concept missions that are currently under study, like Habitable Exoplanet Imaging Mission (HabEx) & Large Ultra-Violet Optical Infra Red (LUVOIR) Surveyor, would discover a large diversity of exoplanets. We propose here classification scheme distinguishes exoplanets into different categories based on their size and incident stellar flux, for the purpose providing expected number observed (yield) with direct imaging missions. The boundaries this can be computed using known...
In this paper we show how tomographic imaging (Zeeman Doppler Imaging, ZDI) can be used to characterize stellar activity and magnetic field topologies, ultimately allowing filter out the radial velocity (RV) jitter of M-dwarf moderate rotators. This work is based on spectropolarimetric observations a sample five weakly-active early M-dwarfs (GJ 205, GJ 358, 410, GJ479, 846) with HARPS-Pol NARVAL. These stars have v sin i RV jitters in range 1-2 km/s 2.7-10.0 m/s rms respectively. Using...
We report results of an extended spectropolarimetric and photometric monitoring the weak-line T Tauri star V830 Tau its recently-detected newborn close-in giant planet. Our observations, carried out within MaTYSSE programme, were spread over 91d, involved ESPaDOnS Narval spectropolarimeters linked to 3.6m Canada-France-Hawaii, 2m Bernard Lyot 8-m Gemini-North Telescopes. Using Zeeman-Doppler Imaging, we characterize surface brightness distributions, magnetic topologies differential rotation...
The description of C3 hydrocarbon chemistry in current photochemical models Titan's atmosphere is found to be far from complete. We have carefully investigated the photochemistry involving C3Hp compounds Titan (considering both photolysis and neutral reactions), which considerably impacts abundances many other species (including C2 compounds). Model results indicate that three (C3, c-C3H2 C3H3) could abundant enough present Cassini/INMS data. Because error bars on predicted C3-hydrocarbon...
We investigate the effects of atmospheric circulation on chemistry hot Jupiter HD 209458b. use a simplified dynamical model and robust chemical network, as opposed to previous studies which have used three dimensional coupled simple kinetics scheme. The temperature structure distribution main constituents are calculated in limit an atmosphere that rotates solid body with equatorial rotation rate 1 km/s. Such motion mimics uniform zonal wind resembles superrotation found by models. uneven...
Abstract We present an atmospheric transmission spectrum for the ultra-hot Jupiter WASP-121b, measured using Space Telescope Imaging Spectrograph on board Hubble . Across 0.47–1 <?CDATA $\mu {\rm{m}}$?> wavelength range, data imply opacity comparable to—and in some spectroscopic channels exceeding—that previously at near-infrared wavelengths (1.15–1.65 ). Wavelength-dependent variations rule out a gray cloud deck confidence level of 3.7 σ and may instead be explained by VO spectral bands....
We report results of a spectropolarimetric and photometric monitoring the weak-line T Tauri star LkCa 4 within Magnetic Topologies Young Stars Survival close-in giant Exoplanets (MaTYSSE) programme, involving ESPaDOnS at Canada–France–Hawaii Telescope. Despite an age only 2 Myr similarity with prototypical classical stars, shows no evidence for accretion probes interesting transition stage planet formation. Large profile distortions Zeeman signatures are detected in unpolarized circularly...
We report results of a spectropolarimetric and photometric monitoring the weak-line T Tauri stars (wTTSs) V819 Tau V830 within MaTYSSE programme, involving ESPaDOnS spectropolarimeter at Canada-France-Hawaii Telescope. At ~3 Myr, both dissipated their discs recently are interesting objects for probing star planet formation. Profile distortions Zeeman signatures detected in unpolarized circularly-polarized lines, whose rotational modulation we modelled using tomographic imaging, yielding...
We present a study of the effect wind-driven advection on chemical composition hot Jupiter atmospheres using fully-consistent 3D hydrodynamics, chemistry and radiative transfer code, Met Office Unified Model (UM). Chemical modelling exoplanet has primarily been restricted to 1D models that cannot account for dynamical processes. In this work we couple relaxation scheme UM interconversion methane carbon monoxide. This is done consistently with meaning departures from equilibrium are included...
We present a publicly available library of model atmospheres with radiative-convective equilibrium Pressure-Temperature ($P$-$T$) profiles fully consistent chemical abundances, and the corresponding emission transmission spectrum R$\sim$5000 at 0.2 $\mu$m decreasing to R$\sim$35 30 $\mu$m, for 89 hot Jupiter exoplanets, four re-circulation factors, six metallicities C/O ratios. find choice condensation process (local/rainout) alters $P$-$T$ profile thereby substantially, potentially...
Transport-induced quenching, i.e., the homogenisation of chemical abundances by atmospheric advection, is thought to occur in atmospheres hot gas giant exoplanets. While some numerical modelling this process exists, three-dimensional nature transport-induced chemistry underexplored. Here we present results 3D cloud- and haze-free simulations HAT-P-11b, HD 189733b, 209458b, WASP-17b including coupled hydrodynamics, radiative transfer chemistry. Our were performed with two schemes: a kinetics...