Publications (73)
SO2, silicate clouds, but no CH4 detected in a warm Neptune
Achrene Dyrek, Michiel Min, Leen Decin +44
WASP-107b is a warm (~740 K) transiting planet with a Neptune-like mass of ~30.5 Earth masses and Jupiter-like radius of ~0.94 Jupiter radius, whose extended atmosphere is eroding.…
Retrieval study of cool, directly imaged exoplanet 51 Eri b
Niall Whiteford, Alistair Glasse, Katy L. Chubb +12
Retrieval methods are a powerful analysis technique for modelling exoplanetary atmospheres by estimating the bulk physical and chemical properties that combine in a forward model t…
The Hubble WFC3 Emission Spectrum of the Extremely-Hot Jupiter, KELT-9b
Quentin Changeat, Billy Edwards
Recent studies of ultra hot-Jupiters suggested that their atmospheres could have thermal inversions due to the presence of optical absorbers such as TiO, VO, FeH and other metal hy…
Original Research By Young Twinkle Students (ORBYTS): Ephemeris Refinement of Transiting Exoplanets
Billy Edwards, Quentin Changeat, Kai Hou Yip +60
We report follow-up observations of transiting exoplanets that have either large uncertainties (>10 minutes) in their transit times or have not been observed for over three years.…
Hubble WFC3 Spectroscopy of the Habitable-zone Super-Earth LHS 1140 b
Billy Edwards, Quentin Changeat, Mayuko Mori +7
Atmospheric characterisation of temperate, rocky planets is the holy grail of exoplanet studies. These worlds are at the limits of our capabilities with current instrumentation in…
ArielRad: the Ariel Radiometric Model
Lorenzo V. Mugnai, Enzo Pascale, Billy Edwards +2
ArielRad, the Ariel radiometric model, is a simulator developed to address the challenges in optimising the space mission science payload and to demonstrate its compliance with the…
On the synergetic use of Ariel and JWST for exoplanet atmospheric science
Quentin Changeat, Pierre-Olivier Lagage, Giovanna Tinetti +27
This paper explores the potential for strategic synergies between the JWST and the Ariel telescopes, two flagship observatories poised to revolutionise the study of exoplanet atmos…
On The Compatibility of Ground-based and Space-based Data: WASP-96 b, An Example
Kai Hou Yip, Quentin Changeat, Billy Edwards +5
The study of exoplanetary atmospheres relies on detecting minute changes in the transit depth at different wavelengths. To date, a number of ground and space based instruments have…
Cool Gaseous Exoplanets: surveying the new frontier with Twinkle
Luke Booth, Subhajit Sarkar, Matt Griffin +1
Cool gaseous exoplanets (, K ~K) are an as-yet understudied population, with great potential to expand our u…
WASP-117 b: an eccentric hot-Saturn as a future complex chemistry laboratory
Lara O. Anisman, Billy Edwards, Quentin Changeat +4
We present spectral analysis of the transiting Saturn-mass planet WASP-117b, observed with the G141 grism of Wide Field Camera 3 (WFC3) on the Hubble Space Telescope. We reduce and…
ARES III: Unveiling the Two Faces of KELT-7 b with HST WFC3
William Pluriel, Niall Whiteford, Billy Edwards +24
We present the analysis of the hot-Jupiter KELT-7b using transmission and emission spectroscopy from the Hubble Space Telescope (HST), both taken with the Wide Field Camera 3 (WFC3…
Small Bodies Science with Twinkle
Billy Edwards, Sean Lindsay, Giorgio Savini +4
Twinkle is an upcoming 0.45m space-based telescope equipped with a visible and two near-infrared spectrometers covering the spectral range 0.4 to 4.5μm with a resolving power R~25…
Is LTT 1445 Ab a Hycean World or a cold Haber World? Exploring the Potential of Twinkle to Unveil Its Nature
Caprice Phillips, Ji Wang, Billy Edwards +3
We explore the prospects for Twinkle to determine the atmospheric composition of the nearby terrestrial-like planet LTT 1445 Ab, including the possibility of detecting the potentia…
A Global Perspective with Updated Constraints on the Ultra-hot Jupiter WASP-19b: Atmospheric Properties and Stellar Activity
Abigail A. Tumborang, Jessica J. Spake, Heather A. Knutson +7
We present a detailed reanalysis of the atmospheric properties of WASP-19b, an ultra-hot Jupiter (1.14 M Jup, 1.41 R Jup) orbiting an active Sun-like star every 0.79 day. We reanal…
Exploring the Ability of HST WFC3 G141 to Uncover Trends in Populations of Exoplanet Atmospheres Through a Homogeneous Transmission Survey of 70 Gaseous Planets
Billy Edwards, Quentin Changeat, Angelos Tsiaras +14
We present the analysis of the atmospheres of 70 gaseous extrasolar planets via transit spectroscopy with Hubble's Wide Field Camera 3 (WFC3). For over half of these, we statistica…
Exoplanet Spectroscopy and Photometry with the Twinkle Space Telescope
Billy Edwards, Malena Rice, Tiziano Zingales +6
The Twinkle space telescope has been designed for the characterisation of exoplanets and Solar System objects. Operating in a low Earth, Sun-synchronous orbit, Twinkle is equipped…
First JWST thermal phase curves of temperate terrestrial exoplanets reveal no thick atmosphere around TRAPPIST-1 b and c
Michaël Gillon, Elsa Ducrot, Taylor J. Bell +30
We report JWST/MIRI 15 m phase curves of TRAPPIST-1 b and c, revealing thermal emission consistent with their irradiation levels, assuming no efficient heat redistribution. We…
Two mini-Neptunes Transiting the Adolescent K-star HIP 113103 Confirmed with TESS and CHEOPS
Nataliea Lowson, George Zhou, Chelsea X. Huang +31
We report the discovery of two mini-Neptunes in near 2:1 resonance orbits ( d for HIP 113103 b and d for HIP 113103 c) around the adolescent K-star HIP 11…
KELT-11 b: Abundances of water and constraints on carbon-bearing molecules from the Hubble transmission spectrum
Quentin Changeat, Billy Edwards, Ahmed F. Al-Refaie +4
In the past decade, the analysis of exoplanet atmospheric spectra has revealed the presence of water vapour in almost all the planets observed, with the exception of a fraction of…
A roadmap for the atmospheric characterization of terrestrial exoplanets with JWST
TRAPPIST-1 JWST Community Initiative, :, Julien de Wit +80
Ultra-cool dwarf stars are abundant, long-lived, and uniquely suited to enable the atmospheric study of transiting terrestrial companions with JWST. Amongst them, the most prominen…
The transmission spectrum of WASP-17 b from the optical to the near-infrared wavelengths: combining STIS, WFC3 and IRAC datasets
Arianna Saba, Angelos Tsiaras, Mario Morvan +6
We present the transmission spectrum of the inflated hot-Jupiter WASP-17 b, observed with the STIS and WFC3 instruments aboard the Hubble Space Telescope, allowing for a continuous…
Is the atmosphere of the ultra-hot Jupiter WASP-121b variable?
Quentin Changeat, Jack W. Skinner, James Y-K. Cho +12
We present a comprehensive analysis of the Hubble Space Telescope observations of the atmosphere of WASP-121 b, a ultra-hot Jupiter. After reducing the transit, eclipse, and phase-…
An Ultra-Short Period Super-Earth and a Sub-Neptune Orbiting the K dwarf TOI-4311
Yoshi Nike Emilia Eschen, Thomas G. Wilson, Andrew Collier Cameron +95
We report the discovery and characterisation of the multi-planetary system around TOI-4311, a K dwarf kinematically between the Galactic thick disk and Hercules stream. TOI-4311 ho…
Remote-sensing Characterisation of Major Solar System Bodies with the Twinkle Space Telescope
Billy Edwards, Giorgio Savini, Giovanna Tinetti +4
Remote-sensing observations of Solar System objects with a space telescope offer a key method of understanding celestial bodies and contributing to planetary formation and evolutio…
ASTEP confirmation of a pair of long-period Jupiter-sized planets with extremely low densities transiting TOI-791
Georgina Dransfield, Antoine C. Petit, Amaury H. M. J. Triaud +45
Gas giant planets with periods orbiting Sun-like stars are a relatively uncommon outcome of planetary formation, and key questions about the nature and form…
ARES V: No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b
Lorenzo V. Mugnai, Darius Modirrousta-Galian, Billy Edwards +25
We present a study on the spatially scanned spectroscopic observations of the transit of GJ 1132 b, a warm (500 K) Super-Earth (1.13 R) that was obtained with the G1…
TrES-1 b: A Case Study in Detecting Secular Evolution of Exoplanet Orbits
Simone R. Hagey, Billy Edwards, Angelos Tsiaras +43
We present a comprehensive analysis of transit, eclipse, and radial velocity data of the hot Jupiter TrES-1 b and confirm evidence of orbital variations on secular timescales. Appa…
Evidence of Long-Term Period Variations in the Exoplanet Transit Database (ETD)
Simone R. Hagey, Billy Edwards, Aaron C. Boley
We analyze a large number of citizen science data and identify eight Hot Jupiter systems that show evidence for deviations from a constant orbital period: HAT-P-19 b, HAT-P-32 b, T…
Lessons Learned from the 1st ARIEL Machine Learning Challenge: Correcting Transiting Exoplanet Light Curves for Stellar Spots
Nikolaos Nikolaou, Ingo P. Waldmann, Angelos Tsiaras +20
The last decade has witnessed a rapid growth of the field of exoplanet discovery and characterisation. However, several big challenges remain, many of which could be addressed usin…
The Albedo Problem and Cloud Cover on Hot Jupiters
Kevin Heng, Billy Edwards, Nicolas B. Cowan
Observations of transiting hot Jupiters have revealed a mismatch between the values of the Bond versus geometric albedos. In the planetary science literature, the ratio of these qu…
In-situ observations of resident space objects with the CHEOPS space telescope
Nicolas Billot, Stephan Hellmich, Willy Benz +80
The CHaracterising ExOPlanet Satellite (CHEOPS) is a partnership between the European Space Agency and Switzerland with important contributions by 10 additional ESA member States.…
Combined analysis of the 12.8 and 15 JWST/MIRI eclipse observations of TRAPPIST-1 b
Elsa Ducrot, Pierre-Olivier Lagage, Michiel Min +36
The first JWST/MIRI photometric observations of TRAPPIST-1 b allowed for the detection of the thermal emission of the planet at 15 , suggesting that the planet could be a bare…
Terminus: A Versatile Simulator for Space-based Telescopes
Billy Edwards, Ian Stotesbury
Space-based telescopes offer unparalleled opportunities for characterising exoplanets, Solar System bodies and stellar objects. However, observatories in low Earth orbits (e.g. Hub…
Revisiting physical parameters of the benchmark brown dwarf LHS 6343 C through a HST/WFC3 secondary eclipse observation
William Frost, Loïc Albert, René Doyon +7
The LHS 6343 system consists of a resolved M-dwarf binary with an evolved, negligibly irradiated brown dwarf, LHS 6343 C, orbiting the primary star. Such brown dwarf eclipsing bina…
Assessment of PLATO Science Performance
Juan Cabrera, Heike Rauer, Reza Samadi +121
The PLATO mission is scheduled for launch early 2027. In this paper we present an overview of the performance drivers for the mission at the time where all flight models of the cam…
Twinkle -- a small satellite spectroscopy mission for the next phase of exoplanet science
Ian Stotesbury, Billy Edwards, Jean-Francois Lavigne +35
With a focus on off-the-shelf components, Twinkle is the first in a series of cost competitive small satellites managed and financed by Blue Skies Space Ltd. The satellite is based…
ESA-Ariel Data Challenge NeurIPS 2022: Inferring Physical Properties of Exoplanets From Next-Generation Telescopes
Kai Hou Yip, Ingo P. Waldmann, Quentin Changeat +11
The study of extra-solar planets, or simply, exoplanets, planets outside our own Solar System, is fundamentally a grand quest to understand our place in the Universe. Discoveries i…
Towards High Precision Mass Measurements of Two Sub-Neptunes in the K2-266 Planetary System Through Transit Timing
Ing-Guey Jiang, Li-Chin Yeh, Billy Edwards +3
Sub-Neptunes have been found to be one of the most common types of exoplanets, yet their physical parameters and properties are poorly determined and in need of further investigati…
A JWST Transit of a Jupiter Analog: II. A Search for Exomoons
David Kipping, Ben Cassese, Quentin Changeat +3
We present a search for exomoons around the Jupiter-like exoplanet Kepler-167e using a NIRSpec JWST transit. Our 60 hour time series clearly reveals the enormous impact of long-ter…
An Ultra-Short Period Super-Earth and Sub-Neptune Spanning the Radius Valley Orbiting the Kinematic Thick Disk Star TOI-2345
Yoshi Nike Emilia Eschen, Thomas G. Wilson, Andrea Bonfanti +94
A crucial chemical link between stars and their orbiting exoplanets is thought to exist. If universal, this connection could affect the formation and evolution of all planets. Ther…
Disentangling Atmospheric Compositions of K2-18 b with Next Generation Facilities
Quentin Changeat, Billy Edwards, Ahmed F. Al-Refaie +3
Recent analysis of the planet K2-18b has shown the presence of water vapour in its atmosphere. While the H2O detection is significant, the Hubble Space Telescope (HST) WFC3 spectru…
The Ariel Target List: The Impact of TESS and the Potential for Characterising Multiple Planets Within a System
Billy Edwards, Giovanna Tinetti
The ESA Ariel mission has been adopted for launch in 2029 and will conduct a survey of around one thousand exoplanetary atmospheres during its primary mission life. By providing ho…
Cloud and Haze Parameterization in Atmospheric Retrievals: Insights from Titan's Cassini Data and JWST Observations of Hot Jupiters
Quentin Changeat, Deborah Bardet, Katy Chubb +4
Context: Before JWST, telescope observations were not sensitive enough to constrain the nature of clouds in exo-atmospheres. Recent observations, however, have inferred cloud signa…
FRECKLL: Full and Reduced Exoplanet Chemical Kinetics distiLLed
Ahmed Faris Al-Refaie, Olivia Venot, Quentin Changeat +1
We introduce a new Python 1D chemical kinetic code FRECKLL (Full and Reduced Exoplanet Chemical Kinetics distiLLed) to evolve large chemical networks efficiently. FRECKLL employs `…
Peeking inside the Black Box: Interpreting Deep Learning Models for Exoplanet Atmospheric Retrievals
Kai Hou Yip, Quentin Changeat, Nikolaos Nikolaou +4
Deep learning algorithms are growing in popularity in the field of exoplanetary science due to their ability to model highly non-linear relations and solve interesting problems in…
An exploration of model degeneracies with a unified phase curve retrieval analysis: The light and dark sides of WASP-43 b
Quentin Changeat, Ahmed F. Al-Refaie, Billy Edwards +2
The analysis of exoplanetary atmospheres often relies upon the observation of transit or eclipse events. While very powerful, these snapshots provide mainly 1-dimensional informati…
Cross-sections for heavy atmospheres: HO self-broadening
Lara O. Anisman, Katy L. Chubb, Quentin Changeat +4
The discovery of super-Earth and mini-Neptune exoplanets means that atmospheric signals from low-mass, temperate exoplanets are being increasingly studied. The signal acquired as t…
A decade of transit photometry for K2-19: Revised system architecture
J. M. Almenara, R. Mardling, A. Leleu +21
The star K2-19 hosts a pair of Neptunian planets deep inside the 3:2 resonance. They induce strong transit-timing variations with two incommensurate frequencies. Previous photodyna…
New Mass and Radius Constraints on the LHS 1140 Planets -- LHS 1140 b is Either a Temperate Mini-Neptune or a Water World
Charles Cadieux, Mykhaylo Plotnykov, René Doyon +43
The two-planet transiting system LHS 1140 has been extensively observed since its discovery in 2017, notably with , HST, TESS, and ESPRESSO, placing strong constraints on…
YunMa: Enabling Spectral Retrievals of Exoplanetary Clouds
Sushuang Ma, Yuichi Ito, Ahmed Faris Al-Refaie +3
In this paper, we present YunMa, an exoplanet cloud simulation and retrieval package, which enables the study of cloud microphysics and radiative properties in exoplanetary atmosph…
A survey of exoplanet phase curves with Ariel
Benjamin Charnay, Joao M. Mendonça, Laura Kreidberg +12
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…
Observing exoplanets in the near-infrared from a high altitude balloon platform
Peter C. Nagler, Billy Edwards, Brian Kilpatrick +8
Although there exists a large sample of known exoplanets, little spectroscopic data exists that can be used to study their global atmospheric properties. This deficiency can be add…
ARES II: Characterising the Hot Jupiters WASP-127 b, WASP-79 b and WASP-62 b with HST
Nour Skaf, Michelle Fabienne Bieger, Billy Edwards +24
This paper presents the atmospheric characterisation of three large, gaseous planets: WASP-127b, WASP-79b and WASP-62b. We analysed spectroscopic data obtained with the G141 grism…
Towards a more complex description of chemical profiles in exoplanets retrievals: A 2-layer parameterisation
Quentin Changeat, Billy Edwards, Ingo Waldmann +1
State of the art spectral retrieval models of exoplanet atmospheres assume constant chemical profiles with altitude. This assumption is justified by the information content of curr…
On-sky validation of image-based adaptive optics wavefront sensor referencing
Nour Skaf, Olivier Guyon, Eric Gendron +14
Differentiating between an exoplanet signal and residual speckle noise is a key challenge in high-contrast imaging. Speckles are due to a combination of fast, slow and static wavef…
Five key exoplanet questions answered via the analysis of 25 hot Jupiter atmospheres in eclipse
Quentin Changeat, Billy Edwards, Ahmed F. Al-Refaie +11
Population studies of exoplanets are key to unlocking their statistical properties. So far the inferred properties have been mostly limited to planetary, orbital and stellar parame…
A JWST Transit of a Jupiter Analog I: Constraints on the Oblateness of Kepler-167e
Ben Cassese, David Kipping, Quentin Changeat +5
In October 2024 JWST observed a transit of Kepler-167e, a Jupiter-analog planet on a 1000+ day orbit. These observations, recorded over a long baseline of nearly 60 hours, were des…
Eclipse Mapping with Ariel: Future Prospects for a Population-Level Mapping Survey
Daniel Valentine, Hannah R. Wakeford, Mark Hammond +4
Eclipse mapping is a powerful tool for measuring 3D profiles of exoplanet atmospheres. To date, only JWST has been capable of widely applying this technique, but as a general obser…
An Updated Study of Potential Targets for Ariel
Billy Edwards, Lorenzo Mugnai, Giovanna Tinetti +2
Ariel has been selected as ESA's M4 mission for launch in 2028 and is designed for the characterisation of a large and diverse population of exoplanetary atmospheres to provide ins…
Original Research By Young Twinkle Students (ORBYTS): Ephemeris Refinement of Transiting Exoplanets II
Billy Edwards, Lara Anisman, Quentin Changeat +60
We report follow-up observations of four transiting exoplanets, TRES-2b, HAT-P-22b, HAT-P-36b and XO-2b, as part of the Original Research By Young Twinkle Students (ORBYTS) program…
ARES I: WASP-76 b, A Tale of Two HST Spectra
Billy Edwards, Quentin Changeat, Robin Baeyens +25
We analyse the transmission and emission spectra of the ultra-hot Jupiter WASP-76b, observed with the G141 grism of the Hubble Space Telescope's Wide Field Camera 3 (WFC3). We redu…
The Transiting Exoplanet Community Early Release Science Program for JWST
Jacob L. Bean, Kevin B. Stevenson, Natalie M. Batalha +99
The James Webb Space Telescope (JWST) presents the opportunity to transform our understanding of planets and the origins of life by revealing the atmospheric compositions, structur…
Observations of PAHs in the atmospheres of discs and exoplanets
Barbara Ercolano, Christian Rab, Karan Molaverdikhani +5
Polycyclic aromatic hydrocarbons (PAHs) play a key role in the chemical and hydrodynamical evolution of the atmospheres of exoplanets and planet-forming discs. If they can survive…
Original Research By Young Twinkle Students (ORBYTS): Ephemeris Refinement of Transiting Exoplanets III
Billy Edwards, Cynthia S. K. Ho, Hannah L. M. Osborne +26
We report photometric follow-up observations of thirteen exoplanets (HATS-1 b, HATS2 b, HATS-3 b, HAT-P-18 b, HAT-P-27 b, HAT-P-30 b, HAT-P-55 b, KELT-4A b, WASP-25 b, WASP-42 b, W…
ARES IV: Probing the atmospheres of the two warm small planets HD 106315 c and HD 3167 c with the HST/WFC3 camera
Gloria Guilluy, Amélie Gressier, Sam Wright +27
We present an atmospheric characterization study of two medium sized planets bracketing the radius of Neptune: HD 106315 c (R=4.98 0.23 R) and HD 3167 c…
Pushing the Limits of Exoplanet Discovery via Direct Imaging with Deep Learning
Kai Hou Yip, Nikolaos Nikolaou, Piero Coronica +13
Further advances in exoplanet detection and characterisation require sampling a diverse population of extrasolar planets. One technique to detect these distant worlds is through th…
HD 21520 b: a warm sub-Neptune transiting a bright G dwarf
Molly Nies, Ismael Mireles, François Bouchy +49
We report the discovery and validation of HD 21520 b, a transiting planet found with TESS and orbiting a bright G dwarf (V=9.2, K, $R_{\star} = 1.04\pm 0.02…
Characterising a World Within the Hot Neptune Desert: Transit Observations of LTT 9779 b with HST WFC3
Billy Edwards, Quentin Changeat, Angelos Tsiaras +27
We present an atmospheric analysis of LTT 9779 b, a rare planet situated in the hot Neptune desert, that has been observed with HST WFC3 G102 and G141. The combined transmission sp…
Measuring Tracers of Planet Formation in the Atmosphere of WASP-77A b: Sub-stellar O/H and C/H ratios, with a stellar C/O ratio and a potentially Super-stellar Ti/H ratio
Billy Edwards, Quentin Changeat
We present a comprehensive atmospheric retrieval study of the hot Jupiter WASP-77A\,b using eclipse observations from the Hubble Space Telescope (HST) and JWST. Using atmospheric r…
ExoClock Project: An open platform for monitoring the ephemerides of Ariel targets with contributions from the public
Anastasia Kokori, Angelos Tsiaras, Billy Edwards +46
The Ariel mission will observe spectroscopically around 1000 exoplanets to further characterise their atmospheres. For the mission to be as efficient as possible, a good knowledge…
Detectability of Rocky-Vapour Atmospheres on Super-Earths with Ariel
Yuichi Ito, Quentin Changeat, Billy Edwards +3
Ariel will mark the dawn of a new era as the first large-scale survey characterising exoplanetary atmospheres with science objectives to address fundamental questions about planeta…
A retrieval challenge exercise for the Ariel mission
Joanna K. Barstow, Quentin Changeat, Katy L. Chubb +5
The Ariel mission, due to launch in 2029, will obtain spectroscopic information for 1000 exoplanets, providing an unprecedented opportunity for comparative exoplanetology. Retrieva…
Alfnoor: A Retrieval Simulation of the Ariel Target List
Quentin Changeat, Ahmed Al-Refaie, Lorenzo V. Mugnai +4
In this work, we present Alfnoor, a dedicated tool optimised for population studies of exoplanet atmospheres. Alfnoor combines the latest version of the retrieval algorithm TauREx…