Publications (67)
Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) III. Atmospheric structure of the misaligned ultra-hot Jupiter WASP-121b
V. Bourrier, D. Ehrenreich, M. Lendl +21
Ultra-hot Jupiters offer interesting prospects for expanding our theories on dynamical evolution and the properties of extremely irradiated atmospheres. In this context, we present…
Characterising brown dwarf companions with IRDIS long-slit spectroscopy: HD 1160 B and HD 19467 B
D. Mesa, V. D'Orazi, A. Vigan +9
The determination of the fundamental properties (mass, separation, age, gravity and atmospheric properties) of brown dwarf companions allows us to infer crucial informations on the…
Characterization of the HD 108236 system with CHEOPS and TESS. Confirmation of a fifth transiting planet
S. Hoyer, A. Bonfanti, A. Leleu +87
The HD108236 system was first announced with the detection of four small planets based on TESS data. Shortly after, the transit of an additional planet with a period of 29.54d was…
Connecting photometric and spectroscopic granulation signals with CHEOPS and ESPRESSO
S. Sulis, M. Lendl, H. Cegla +83
Stellar granulation generates fluctuations in photometric and spectroscopic data whose properties depend on the stellar type, composition, and evolutionary state. In this study, we…
A transit survey to search for planets around hot subdwarfs: I. methods and performance tests on light curves from Kepler, K2, TESS, and CHEOPS
V. Van Grootel, F. J. Pozuelos, A. Thuillier +79
Context. Hot subdwarfs experienced strong mass loss on the Red Giant Branch (RGB) and are now hot and small He-burning objects. Aims. In this project we aim to perform a transit su…
The hot dayside and asymmetric transit of WASP-189b seen by CHEOPS
M. Lendl, Sz. Csizmadia, A. Deline +102
The CHEOPS space mission dedicated to exoplanet follow-up was launched in December 2019, equipped with the capacity to perform photometric measurements at the 20 ppm level. As CHEO…
The long egress of GJ~436b's giant exosphere
B. Lavie, D. Ehrenreich, V. Bourrier +8
The M dwarf GJ 436 hosts a transiting warm Neptune known to experience atmospheric escape. Previous observations revealed the presence of a giant hydrogen exosphere transiting the…
Hot Rocks Survey II: The thermal emission of TOI-1468 b reveals a hot bare rock
E. A. Meier Valdés, B. -O. Demory, H. Diamond-Lowe +17
Terrestrial exoplanets orbiting nearby small, cool stars known as M dwarfs are well suited for atmospheric characterisation. Given the strong XUV irradiation from M dwarf host star…
X-ray illumination of the ejecta of Supernova 1987A
J. Larsson, C. Fransson, G. Ãstlin +25
We present the late-time optical light curve of the ejecta of SN 1987A measured from HST imaging observations spanning the past 17 years. We find that the flux from the ejecta decl…
CHEOPS finds KELT-1b darker than expected in visible light: Discrepancy between the CHEOPS and TESS eclipse depths
H. Parviainen, T. G. Wilson, M. Lendl +78
Recent TESS-based studies have suggested that the dayside of KELT-1b, a strongly-irradiated brown dwarf, is significantly brighter in visible light than what would be expected base…
JWST reveals a rapid and strong day side variability of 55 Cancri e
J. A. Patel, A. Brandeker, D. Kitzmann +16
The nature of the close-in rocky planet 55 Cnc e is puzzling despite having been observed extensively. Its optical and infrared occultation depths show temporal variability, in add…
Clouds and Chemistry Across the Brown Dwarf T-Y Sequence: Insights from JWST Atmospheric Retrievals
A. Lueber, D. Kitzmann, K. Heng
The James Webb Space Telescope (JWST) offers exceptional spectral resolution and wavelength coverage, which are essential for studying the coldest brown dwarfs, particularly Y dwar…
Planet Hunters X. KIC 8462852 - Where's the Flux?
T. S. Boyajian, D. M. LaCourse, S. A. Rappaport +46
Over the duration of the Kepler mission, KIC8462852 was observed to undergo irregularly shaped, aperiodic dips in flux of up to \%. The dipping activity can last for betwe…
The unstable CO2 feedback cycle on ocean planets
D. Kitzmann, Y. Alibert, M. Godolt +6
Ocean planets are volatile rich planets, not present in our Solar System, which are thought to be dominated by deep, global oceans. This results in the formation of high-pressure w…
Analysis of Early Science observations with the CHaracterising ExOPlanets Satellite (CHEOPS) using pycheops
P. F. L. Maxted, D. Ehrenreich, T. G. Wilson +77
CHEOPS(CHaracterising ExOPlanet Satellite) is an ESA S-class mission that observes bright stars at high cadence from low-Earth orbit. The main aim of the mission is to characterize…
The phase curve and the geometric albedo of WASP-43b measured with CHEOPS, TESS and HST WFC3/UVIS
G. Scandariato, V. Singh, D. Kitzmann +79
Observations of the phase curves and secondary eclipses of extrasolar planets provide a window on the composition and thermal structure of the planetary atmospheres. For example, t…
A full transit of Lupi d and the search for an exomoon in its Hill sphere with CHEOPS
D. Ehrenreich, L. Delrez, B. Akinsanmi +90
The planetary system around the naked-eye star Lupi (HD 136352; TOI-2011) is composed of three exoplanets with masses of 4.7, 11.2, and 8.6 Earth masses. The TESS and CHEOPS…
A Benchmark JWST Near-Infrared Spectrum for the Exoplanet WASP-39b
A. L. Carter, E. M. May, N. Espinoza +77
Observing exoplanets through transmission spectroscopy supplies detailed information on their atmospheric composition, physics, and chemistry. Prior to JWST, these observations wer…
The atmosphere and architecture of WASP-189 b probed by its CHEOPS phase curve
A. Deline, M. J. Hooton, M. Lendl +83
Gas giants orbiting close to hot and massive early-type stars can reach dayside temperatures that are comparable to those of the coldest stars. These "ultra-hot Jupiters" have atmo…
Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) - II. A broadened sodium feature on the ultra-hot giant WASP-76b
J. V. Seidel, D. Ehrenreich, A. Wyttenbach +18
High-resolution optical spectroscopy is a powerful tool to characterise exoplanetary atmospheres from the ground. The sodium D lines, with their large cross sections, are especiall…
Investigating the visible phase-curve variability of 55 Cnc e
E. A. Meier Valdés, B. M. Morris, B. -O. Demory +87
55 Cnc e is an ultra-short period super-Earth transiting a Sun-like star. Previous observations in the optical range detected a time-variable flux modulation that is phased with th…
A CHEOPS-enhanced view of the HD3167 system
V. Bourrier, A. Deline, A. Krenn +92
Much remains to be understood about the nature of exoplanets smaller than Neptune, most of which have been discovered in compact multi-planet systems. With its inner ultra-short pe…
Two temperate super-Earths transiting a nearby late-type M dwarf
L. Delrez, C. A. Murray, F. J. Pozuelos +82
In the age of JWST, temperate terrestrial exoplanets transiting nearby late-type M dwarfs provide unique opportunities for characterising their atmospheres, as well as searching fo…
Characterising exoplanets and their environment with UV transmission spectroscopy
L. Fossati, V. Bourrier, D. Ehrenreich +36
Exoplanet science is now in its full expansion, particularly after the CoRoT and Kepler space missions that led us to the discovery of thousands of extra-solar planets. The last de…
55 Cancri e's occultation captured with CHEOPS
B. -O. Demory, S. Sulis, E. Meier Valdes +73
Past occultation and phase-curve observations of the ultra-short period super-Earth 55 Cnc e obtained at visible and infrared wavelengths have been challenging to reconcile with a…
Six transiting planets and a chain of Laplace resonances in TOI-178
A. Leleu, Y. Alibert, N. C. Hara +152
Determining the architecture of multi-planetary systems is one of the cornerstones of understanding planet formation and evolution. Resonant systems are especially important as the…
The EBLM project -- VIII. First results for M-dwarf mass, radius and effective temperature measurements using CHEOPS light curves
M. I. Swayne, P. F. L. Maxted, A. H. M. J. Triaud +93
The accuracy of theoretical mass, radius and effective temperature values for M-dwarf stars is an active topic of debate. Differences between observed and theoretical values have r…
CHEOPS and TESS view of the ultra-short period super-Earth TOI-561 b
J. A. Patel, J. A. Egger, T. G. Wilson +75
Ultra-short period planets (USPs) are a unique class of super-Earths with an orbital period of less than a day and hence subject to intense radiation from their host star. While mo…
The MOPYS project: A survey of 70 planets in search of extended He I and H atmospheres. No evidence of enhanced evaporation in young planets
J. Orell-Miquel, F. Murgas, E. Pallé +30
During the first Gyr of their life, exoplanet atmospheres suffer from different atmospheric escape phenomena that can strongly affect the shape and morphology of the exoplanet itse…
Enceladus and Jupiter as exoplanets: the opposition surge effect
K. Jones, B. M. Morris, K. Heng
Planets and moons in our Solar System have strongly peaked reflected light phase curves at opposition. In this work, we produce a modified reflected light phase curve model and use…
The Effect of Atmospheric Chemistry on the Optical Geometric Albedos of Hot Jupiters
K. D. Jones, B. M. Morris, K. Heng
We investigate the geometric albedos of hot Jupiters by comparing observational data from space telescopes TESS, Kepler, CoRoT, and CHEOPS against theoretical models. The study aim…
Exoplanet Characterization by Multi-Observatory Transit Photometry with TESS and CHEOPS
E. Gaidos, D. Kitzmann, K. Heng
Space-based photometric surveys have discovered large numbers of planets transiting other stars, but these observe in a single band-pass and yield only the planet radius, orbital p…
Optical phase curve of the ultra-hot Jupiter WASP-121b
V. Bourrier, D. Kitzmann, T. Kuntzer +28
We present the analysis of TESS optical photometry of WASP-121b, which reveal the phase curve of this transiting ultra-hot Jupiter. Its hotspot is located at the substellar point,…
A super-Earth and a sub-Neptune orbiting the bright, quiet M3 dwarf TOI-1266
B. -O. Demory, F. J. Pozuelos, Y. Gomez Maqueo Chew +70
We report the discovery and characterisation of a super-Earth and a sub-Neptune transiting the bright (), quiet, and nearby (37 pc) M3V dwarf TOI-1266. We validate the plane…
The HD 93963 A transiting system: A 1.04d super-Earth and a 3.65 d sub-Neptune discovered by TESS and CHEOPS
L. M. Serrano, D. Gandolfi, S. Hoyer +109
We present the discovery of two small planets transiting HD 93963A (TOI-1797), a G0\,V star (M=1.109\,\,0.043\,M, R=1.043\,\,0.009\,R) in a visual…
Discovery of TOI-1260d and the characterisation of the multi-planet system
Kristine W. F. Lam, J. Cabrera, M. J. Hooton +83
We report the discovery of a third planet transiting the star TOI-1260, previously known to host two transiting sub-Neptune planets with orbital periods of 3.127 and 7.493 days, re…
Transit timing variations of AU Microscopii b and c
Gy. M. Szabó, Z. Garai, A. Brandeker +76
Here we report large-amplitude transit timing variations (TTVs) for AU\,Microcopii b and c as detected in combined TESS (2018, 2020) and CHEOPS (2020, 2021) transit observations. A…
CHEOPS geometric albedo of the hot Jupiter HD 209458b
A. Brandeker, K. Heng, M. Lendl +74
We report the detection of the secondary eclipse of the hot Jupiter HD 209458b in optical/visible light using the CHEOPS space telescope. Our measurement of 20.4 +/- 3.3 ppm transl…
CHEOPS observations of the HD 108236 planetary system: A fifth planet, improved ephemerides, and planetary radii
A. Bonfanti, L. Delrez, M. J. Hooton +106
The detection of a super-Earth and three mini-Neptunes transiting the bright ( = 9.2 mag) star HD 108236 (also known as TOI-1233) was recently reported on the basis of TESS and…
CHEOPS Precision Phase Curve of the Super-Earth 55 Cnc e
B. M. Morris, L. Delrez, A. Brandeker +79
55 Cnc e is a transiting super-Earth (radius and mass ) orbiting a G8V host star on a 17-hour orbit. Spitzer observations of the planet's phase…
Global flow regimes of hot Jupiters
C. Akın, K. Heng, J. M. Mendonça +2
In hot and ultra-hot Jupiters, stellar irradiation is a primary driver of atmospheric circulation and the wave structures that sustain it. We aim to investigate how variations in r…
Dynamics of Y Dwarf Atmospheres
C. Akın, E. K. H. Lee, L. Gkouvelis +1
The global circulation regime of the coolest brown dwarfs, the Y dwarfs, remains largely unexplored. We investigate the interplay between convection, rotation, and cloud thermal fe…
Retrieving day- and nightside atmospheric properties of the ultra-hot Jupiter TOI-2109b. Detection of Fe and CO emission lines and evidence for inefficient heat transport
D. Cont, L. Nortmann, F. Lesjak +32
The ultra-hot Jupiter (UHJ) TOI-2109b marks the lower edge of the equilibrium temperature gap between 3500 K and 4500 K, an unexplored thermal regime that separates KELT-9b, the ho…
Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) I. Detection of hot neutral sodium at high altitudes on WASP-49b
A. Wyttenbach, C. Lovis, D. Ehrenreich +13
High-resolution optical spectroscopy during the transit of HD 189733b, a prototypical hot Jupiter, allowed the resolution of the Na I D sodium lines in the planet, giving access to…
The stable climate of KELT-9b
K. D. Jones, B. M. Morris, B. -O. Demory +76
Even among the most irradiated gas giants, so-called ultra-hot Jupiters, KELT-9b stands out as the hottest planet thus far discovered with a dayside temperature of over 4500K. At t…
Spi-OPS: Spitzer and CHEOPS confirm the near-polar orbit of MASCARA-1 b and reveal a hint of dayside reflection
M. J. Hooton, S. Hoyer, D. Kitzmann +82
The light curves of tidally locked hot Jupiters transiting fast-rotating, early-type stars are a rich source of information about both the planet and star, with full-phase coverage…
Three-dimensional distribution of ejecta in Supernova 1987A at 10 000 days
J. Larsson, C. Fransson, J. Spyromilio +19
Due to its proximity, SN 1987A offers a unique opportunity to directly observe the geometry of a stellar explosion as it unfolds. Here we present spectral and imaging observations…
The Mantis Network IV: A titanium cold-trap on the ultra-hot Jupiter WASP-121 b
H. J. Hoeijmakers, D. Kitzmann, B. M. Morris +10
Observations of WASP-121 b have suggested an under-abundance of titanium and titanium-oxide from its terminator region. In this study, we aim to determine whether this depletion is…
A stellar occultation by the transneptunian object (50000) Quaoar observed by CHEOPS
B. E. Morgado, G. Bruno, A. R. Gomes-Júnior +82
Stellar occultation is a powerful technique that allows the determination of some physical parameters of the occulting object. The result depends on the photometric accuracy, the t…
Glancing through the debris disk: Photometric analysis of DE Boo with CHEOPS
Ã. Boldog, Gy. M. Szabó, L. Kriskovics +76
DE Boo is a unique system, with an edge-on view through the debris disk around the star. The disk, which is analogous to the Kuiper belt in the Solar System, was reported to extend…
Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM
Z. Rustamkulov, D. K. Sing, S. Mukherjee +91
Transmission spectroscopy of exoplanets has revealed signatures of water vapor, aerosols, and alkali metals in a few dozen exoplanet atmospheres. However, these previous inferences…
The EBLM project -- IX. Five fully convective M-dwarfs, precisely measured with CHEOPS and TESS light curves
D. Sebastian, M. I. Swayne, P. F. L. Maxted +85
Eclipsing binaries are important benchmark objects to test and calibrate stellar structure and evolution models. This is especially true for binaries with a fully convective M-dwar…
The PLATO 2.0 Mission
H. Rauer, C. Catala, C. Aerts +159
PLATO 2.0 has recently been selected for ESA's M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it…
Challenges facing young astrophysicists
N. L. Zakamska, A. E. Schulz, K. Heng +9
In order to attract and retain excellent researchers and diverse individuals in astrophysics, we recommend action be taken in several key areas impacting young scientists: (1) Main…
The geometric albedo of the hot Jupiter HD 189733b measured with CHEOPS
A. F. Krenn, M. Lendl, J. A. Patel +84
Context. Measurements of the occultation of an exoplanet at visible wavelengths allow us to determine the reflective properties of a planetary atmosphere. The observed occultation…
The changing face of AU Mic b: stellar spots, spin-orbit commensurability, and Transit Timing Variations as seen by CHEOPS and TESS
Gy. M. Szabó, D. Gandolfi, A. Brandeker +78
AU Mic is a young planetary system with a resolved debris disc showing signs of planet formation and two transiting warm Neptunes near mean-motion resonances. Here we analyse three…
The Mantis Network III: Expanding the limits of chemical searches within ultra hot-Jupiters. New detections of Ca I, V I, Ti I, Cr I, Ni I, Sr II, Ba II, and Tb II in KELT-9 b
N. W. Borsato, H. J. Hoeijmakers, B. Prinoth +5
Cross-correlation spectroscopy is an invaluable tool in the study of exoplanets. However, aliasing between spectral lines makes it vulnerable to systematic biases. This work strive…
EChO - Exoplanet Characterisation Observatory
G. Tinetti, J. P. Beaulieu, T. Henning +131
A dedicated mission to investigate exoplanetary atmospheres represents a major milestone in our quest to understand our place in the universe by placing our Solar System in context…
Hint of an exocomet transit in the CHEOPS lightcurve of HD 172555
F. Kiefer, V. Van Grootel, A. Lecavelier des Etangs +72
HD172555 is a young (20Myr) A7V star surrounded by a 10au wide debris disk suspected to be replenished partly by collisions between large planetesimals. Small eva…
Examining the orbital decay targets KELT-9 b, KELT-16 b and WASP-4 b, and the transit-timing variations of HD 97658 b
J. -V. Harre, A. M. S. Smith, S. C. C. Barros +87
Tidal orbital decay is suspected to occur especially for hot Jupiters, with the only observationally confirmed case of this being WASP-12 b. By examining this effect, information o…
Orbital and spectral analysis of the benchmark brown dwarf HD 4747B
S. Peretti, D. Ségransan, B. Lavie +43
The study of high contrast imaged brown dwarfs and exoplanets depends strongly on evolutionary models. To estimate the mass of a directly imaged substellar object, its extracted ph…
Fundamental effective temperature measurements for eclipsing binary stars -- III. SPIRou near-infrared spectroscopy and CHEOPS photometry of the benchmark G0V star EBLM J0113+31
P. F. L. Maxted, N. J. Miller, S. Hoyer +74
EBLM J0113+31 is moderately bright (V=10.1), metal-poor ([Fe/H]) G0V star with a much fainter M dwarf companion on a wide, eccentric orbit (=14.3 d). We have used near…
TOI-2257 b: A highly eccentric long-period sub-Neptune transiting a nearby M dwarf
N. Schanche, F. J. Pozuelos, M. N. Günther +61
Thanks to the relative ease of finding and characterizing small planets around M dwarf stars, these objects have become cornerstones in the field of exoplanet studies. The current…
A generalized bayesian inference method for constraining the interiors of super Earths and sub-Neptunes
C. Dorn, J. Venturini, A. Khan +5
We aim to present a generalized Bayesian inference method for constraining interiors of super Earths and sub-Neptunes. Our methodology succeeds in quantifying the degeneracy and co…
Chemical diversity of the atmospheres and interiors of sub-Neptunes: a case study of GJ 436 b
A. Guzmán-Mesa, D. Kitzmann, C. Mordasini +1
The atmospheres of sub-Neptunes are expected to exhibit considerable chemical diversity, beyond what is anticipated for gas-giant exoplanets. In the current study, we construct sel…
Investigating the architecture and internal structure of the TOI-561 system planets with CHEOPS, HARPS-N and TESS
G. Lacedelli, T. G. Wilson, L. Malavolta +115
We present a precise characterization of the TOI-561 planetary system obtained by combining previously published data with TESS and CHEOPS photometry, and a new set of HARPS-N…
Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) VIII. Nondetection of sodium in the atmosphere of the aligned planet KELT-10b
M. Steiner, O. Attia, D. Ehrenreich +17
We searched for potential atmospheric species in KELT-10b, focusing on sodium doublet lines (Na i; 589 nm) and the Balmer alpha line (H ; 656 nm) in the transmission spectrum.…