Publications (48)
Dark skies of the slightly eccentric WASP-18 b from its optical-to-infrared dayside emission
A. Deline, P. E. Cubillos, L. Carone +86
We performed a joint analysis of phase-curve observations of the ultra-hot Jupiter WASP-18 b from the visible to the mid-infrared, using data from CHEOPS, TESS and Spitzer. We aim…
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…
Clouds in the atmospheres of extrasolar planets. II. Thermal emission spectra of Earth-like planets influenced by low and high-level clouds
D. Kitzmann, A. B. C. Patzer, P. von Paris +2
We study the impact of multi-layered clouds (low-level water and high-level ice clouds) on the thermal emission spectra of Earth-like planets orbiting different types of stars. Clo…
TOI-4616 b: a benchmark Earth-sized planet transiting a nearby M4 dwarf
F. Zong Lang, B. O. Demory, Y. Gomez Maqueo Chew +44
Rocky exoplanets are particularly abundant around M-type stars. Their small radii and low luminosities provide favourable conditions for detecting transiting terrestrial planets an…
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…
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…
Searching for Hot Water World Candidates with CHEOPS: Refining the radii and analysing the internal structures and atmospheric lifetimes of TOI-238 b and TOI-1685 b
J. A. Egger, D. Kubyshkina, Y. Alibert +85
Studying the composition of exoplanets is one of the most promising approaches to observationally constrain planet formation and evolution processes. However, this endeavour is com…
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 multi-planet system TOI-5624: Four transiting sub-Neptunes with an outer companion revealed by transit-timing variations
A. Bonfanti, D. Gandolfi, P. Leonardi +96
Following the 2022 alert of a TESS object of interest transiting TOI-5624 (a G7 V star 100 pc away), a CHEOPS campaign in 2023 detected four planetary signals at $P_b\approx3…
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…
Small but mighty: High-resolution spectroscopy of ultra-hot Jupiter atmospheres with compact telescopes. KELT-9 b's transmission spectrum with Wendelstein's FOCES Spectrograph
N. W. Borsato, H. J. Hoeijmakers, D. Cont +9
When observing transmission spectra produced by atmospheres of ultra-hot Jupiters, large telescopes are typically the instrument of choice due to the very weak signal of the planet…
Simultaneous multicolour optical and near-IR transit photometry of GJ 1214b with SOFIA
D. Angerhausen, C. Dreyer, B. Placek +24
The benchmark exoplanet GJ 1214b is one of the best studied transiting planets in the transition zone between rocky Earth-sized planets and gas or ice giants. This class of super-E…
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…
Time Resolved Absorption of Six Chemical Species With MAROON-X Points to Strong Drag in the Ultra Hot Jupiter TOI-1518 b
A. Simonnin, V. Parmentier, J. P. Wardenier +27
Wind dynamics play a pivotal role in governing transport processes within planetary atmospheres, influencing atmospheric chemistry, cloud formation, and the overall energy budget.…
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…
Probing the atmosphere of HD189733b with the Na I and K I lines
E. Keles, D. Kitzmann, M. Mallonn +12
High spectral resolution transmission spectroscopy is a powerful tool to characterize exoplanet atmospheres. Especially for hot Jupiters, this technique is highly relevant, due to…
Discontinuous Galerkin finite element methods for radiative transfer in spherical symmetry
D. Kitzmann, J. Bolte, A. B. C. Patzer
The discontinuous Galerkin finite element method (DG-FEM) is successfully applied to treat a broad variety of transport problems numerically. In this work, we use the full capacity…
The extrasolar planet GL 581 d: A potentially habitable planet?
P. von Paris, S. Gebauer, M. Godolt +6
The planetary system around the M star Gliese 581 contains at least three close-in potentially low-mass planets, GL 581 c, d, and e. In order to address the question of the habitab…
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…
Large Interferometer For Exoplanets (LIFE): III. Spectral resolution, wavelength range and sensitivity requirements based on atmospheric retrieval analyses of an exo-Earth
B. S. Konrad, E. Alei, D. Angerhausen +9
Temperate terrestrial exoplanets are likely common objects, but their discovery and characterization is very challenging. Concepts for optimized space missions to overcome these ch…
Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) IV. A spectral inventory of atoms and molecules in the high-resolution transmission spectrum of WASP-121 b
H. J. Hoeijmakers, J. V. Seidel, L. Pino +22
Aims: We survey the transmission spectrum of WASP-121 b for line-absorption by metals and molecules at high spectral resolution, and elaborate on existing interpretations of the op…
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…
3D climate modeling of Earth-like extrasolar planets orbiting different types of host stars
M. Godolt, J. L. Grenfell, A. Hamann-Reinus +7
The potential habitability of a terrestrial planet is usually defined by the possible existence of liquid water on its surface. The potential presence of liquid water depends on ma…
Clouds in the atmospheres of extrasolar planets. I. Climatic effects of multi-layered clouds for Earth-like planets and implications for habitable zones
D. Kitzmann, A. B. C. Patzer, P. von Paris +5
The effects of multi-layered clouds in the atmospheres of Earth-like planets orbiting different types of stars are studied. The radiative effects of cloud particles are directly co…
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…
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…
An atlas of resolved spectral features in the transmission spectrum of WASP-189 b with MAROON-X
B. Prinoth, H. J. Hoeijmakers, B. M. Morris +10
Exoplanets in the ultra-hot Jupiter regime provide an excellent laboratory for testing the impact of stellar irradiation on the dynamics and chemical composition of gas giant atmos…
The extrasolar planet Gliese 581 d: a potentially habitable planet? (Corrigendum to arXiv:1009.5814)
P. von Paris, S. Gebauer, M. Godolt +6
We report here that the equation for H2O Rayleigh scattering was incorrectly stated in the original paper [arXiv:1009.5814]. Instead of a quadratic dependence on refractivity r, we…
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…
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…
Titanium chemistry of WASP-121 b with ESPRESSO in 4-UT mode
B. Prinoth, J. V. Seidel, H. J. Hoeijmakers +15
Transit spectroscopy usually relies on the integration of one or several transits to achieve the S/N necessary to resolve spectral features. Consequently, high-S/N observations of…
Detection of faculae in the transit and transmission spectrum of WASP-69b
D. J. M. Petit dit de la Roche, H. Chakraborty, M. Lendl +9
Context: Transmission spectroscopy is a powerful tool for understanding exoplanet atmospheres. At optical wavelengths, it makes it possible to infer the composition and the presenc…
Clouds in the atmospheres of extrasolar planets. IV. On the scattering greenhouse effect of CO2 ice particles: Numerical radiative transfer studies
D. Kitzmann, A. B. C. Patzer, H. Rauer
Owing to their wavelengths dependent absorption and scattering properties, clouds have a strong impact on the climate of planetary atmospheres. Especially, the potential greenhouse…
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…
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…
Assessing the habitability of planets with Earth-like atmospheres with 1D and 3D climate modeling
M. Godolt, J. L. Grenfell, D. Kitzmann +5
The habitable zone (HZ) describes the range of orbital distances around a star where the existence of liquid water on the surface of an Earth-like planet is in principle possible.…
The dependence of the ice-albedo feedback on atmospheric properties
P. von Paris, F. Selsis, D. Kitzmann +1
The ice-albedo feedback is a potentially important de-stabilizing effect for the climate of terrestrial planets. It is based on the positive feedback between decreasing surface tem…
A spectral survey of an ultra-hot Jupiter: Detection of metals in the transmission spectrum of KELT-9 b
H. J. Hoeijmakers, D. Ehrenreich, D. Kitzmann +16
Context: KELT-9 b exemplifies a newly emerging class of short-period gaseous exoplanets that tend to orbit hot, early type stars - termed ultra-hot Jupiters. The severe stellar irr…
CHEOPS photometry from 2024 reveals a reversal in the transit-timing variations of AU Mic c
Z. Garai, Gy. M. Szabó, D. Gandolfi +90
We present new CHEOPS transit observations of AU Mic b and AU Mic c obtained between June and September 2024, extending the baseline of transit-timing measurements of this young pl…
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…
Large Interferometer For Exoplanets (LIFE): IX. Assessing the Impact of Clouds on Atmospheric Retrievals at Mid-Infrared Wavelengths with a Venus-Twin Exoplanet
B. S. Konrad, E. Alei, S. P. Quanz +10
The Large Interferometer For Exoplanets (LIFE) initiative aims to develop a space based mid-infrared (MIR) nulling interferometer to measure the thermal emission spectra of tempera…
Clouds in the atmospheres of extrasolar planets. III. Impact of low and high-level clouds on the reflection spectra of Earth-like planets
D. Kitzmann, A. B. C. Patzer, P. von Paris +2
We study the influence of low-level water and high-level ice clouds on low-resolution reflection spectra and planetary albedos of Earth-like planets orbiting different types of sta…
FastChem: A computer program for efficient complex chemical equilibrium calculations in the neutral/ionized gas phase with applications to stellar and planetary atmospheres
J. W. Stock, D. Kitzmann, A. B. C. Patzer +1
For the calculation of complex neutral/ionized gas phase chemical equilibria, we present a semi-analytical versatile and efficient computer program, called FastChem. The applied me…
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,…
Accreting protoplanets: Spectral signatures and magnitude of gas and dust extinction at H alpha
G. -D. Marleau, Y. Aoyama, R. Kuiper +14
Accreting planets have been seen at Ha (H alpha), but targeted searches have not been fruitful. For planets, accretion tracers should come from the shock itself, exposing them to e…
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…
TESS phase curve of ultra-hot Jupiter WASP-189 b
J. A. Patel, D. Kitzmann, A. Brandeker +4
The thermal structures of highly irradiated ultra-hot Jupiters can deviate substantially from those of cooler hot Jupiters. For planets orbiting rapidly rotating, and consequently…