Search Publications
Characterising TOI-732 b and c: New insights into the M-dwarf radius and density valley
Alonso, R.; Deleuil, M.; Erikson, A. +88 more
Context. TOI-732 is an M dwarf hosting two transiting planets that are located on the two opposite sides of the radius valley. Inferring a reliable demographics for this type of systems is key to understanding their formation and evolution mechanisms.
Aims: By doubling the number of available space-based observations and increasing the number…
CHEOPS in-flight performance. A comprehensive look at the first 3.5 yr of operations
Guterman, P.; Alonso, R.; Deleuil, M. +128 more
Context. Since the discovery of the first exoplanet almost three decades ago, the number of known exoplanets has increased dramatically. By beginning of the 2000s it was clear that dedicated facilities to advance our studies in this field were needed. The CHaracterising ExOPlanet Satellite (CHEOPS) is a space telescope specifically designed to mon…
The SOPHIE search for northern extrasolar planets: XIX. A system including a cold sub-Neptune potentially transiting a V = 6.5 star HD 88986
Bouchy, F.; Deleuil, M.; Moutou, C. +51 more
Transiting planets with orbital periods longer than 40 d are extremely rare among the 5000+ planets discovered so far. The lack of discoveries of this population poses a challenge to research into planetary demographics, formation, and evolution. Here, we present the detection and characterization of HD 88986 b, a potentially transiting sub-Neptun…
Constraining the reflective properties of WASP-178 b using CHEOPS photometry
Alonso, R.; Deleuil, M.; Erikson, A. +79 more
Context. Multiwavelength photometry of the secondary eclipses of extrasolar planets is able to disentangle the reflected and thermally emitted light radiated from the planetary dayside. Based on this, we can measure the planetary geometric albedo Ag, which is an indicator of the presence of clouds in the atmosphere, and the recirculatio…
Unveiling the internal structure and formation history of the three planets transiting HIP 29442 (TOI-469) with CHEOPS
Alonso, R.; Deleuil, M.; Erikson, A. +91 more
Multiplanetary systems spanning the radius valley are ideal testing grounds for exploring the different proposed explanations for the observed bimodality in the radius distribution of close-in exoplanets. One such system is HIP 29442 (TOI-469), an evolved K0V star hosting two super-Earths and one sub-Neptune. We observed HIP 29442 with CHEOPS for …
The EBLM Project- XI. Mass, radius, and effective temperature measurements for 23 M-dwarf companions to solar-type stars observed with CHEOPS
Alonso, R.; Deleuil, M.; Erikson, A. +104 more
Observations of low-mass stars have frequently shown a disagreement between observed stellar radii and radii predicted by theoretical stellar structure models. This 'radius inflation' problem could have an impact on both stellar and exoplanetary science. We present the final results of our observation programme with the CHaracterising ExOPlanet Sa…
Planets observed with CHEOPS. Two super-Earths orbiting the red dwarf star TOI-776
Alonso, R.; Deeg, H.; Deleuil, M. +86 more
Context. M-dwarf stars are the most common of potential exoplanet host stars in the Galaxy. It is therefore very important to understand planetary systems orbiting such stars and to determine the physical parameters of such planets with high precision. Also with the launch of the James Webb Space Telescope (JWST) the observation of atmospheric par…
CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side
Alonso, R.; Deleuil, M.; Erikson, A. +87 more
Context. Occultations are windows of opportunity to indirectly peek into the dayside atmosphere of exoplanets. High-precision transit events provide information on the spin-orbit alignment of exoplanets around fast-rotating hosts.
Aims: We aim to precisely measure the planetary radius and geometric albedo of the ultra-hot Jupiter (UHJ) KELT-2…
Exploring the ultra-hot Jupiter WASP-178b. Constraints on atmospheric chemistry and dynamics from a joint retrieval of VLT/CRIRES+ and space photometric data
Nagel, E.; Czesla, S.; Nortmann, L. +14 more
Despite recent progress in the spectroscopic characterization of individual exoplanets, the atmospheres of key ultra-hot Jupiters (UHJs) still lack comprehensive investigations. These include WASP-178b, one of the most irradiated UHJs known to date. We observed the dayside emission signal of this planet with CRIRES+ in the spectral K ba…
Asymmetry in the atmosphere of the ultra-hot Jupiter WASP-76 b
Alonso, R.; Deleuil, M.; Erikson, A. +79 more
Context. WASP-76 b has been a recurrent subject of study since the detection of a signature in high-resolution transit spectroscopy data indicating an asymmetry between the two limbs of the planet. The existence of this asymmetric signature has been confirmed by multiple studies, but its physical origin is still under debate. In addition, it contr…