Explanipedia

HARPS-N, TESS, and CHEOPS discover a transiting sub-Neptune and two outer companions around the bright solar analogue HD 85426 Open

A. Mortier, A. Collier Cameron, A. Anna John, David W. Latham, L. Malavolta , et al. · 2025

We provide a detailed characterisation of the planetary system orbiting HD 85426 (TOI-1774). This bright G-type star (M*: 0.99 M⊙; R*: 1.13 R⊙; age: 7.4 Gyr; V mag: 8.25) hosts a transiting sub-Neptune, HD 85426 b, with an orbital period o…

A high geometric albedo and small size for the Haumea cluster member (24835) 1995 SM <sub>55</sub> determined from a stellar occultation and photometric observations Open

J. L. Ortiz, N. Morales, B. Sicardy, F. L. Rommel, F. Braga-Ribas , et al. · 2025

Context . Trans-Neptunian objects (TNOs) are thought to be some of the most ancient and primitive bodies in our Solar System. Understanding their basic physical properties is crucial to unraveling their origin and the evolution of the oute…

Dark skies of the slightly eccentric WASP-18 b from its optical-to-infrared dayside emission Open

A. Deline, P. E. Cubillos, L. Carone, Brice-Olivier Demory, M. Lendl , et al. · 2025

Context . Ultra-hot Jupiters (UHJs) are gas giant exoplanets that are strongly irradiated by their star, setting intense molecular dissociation that leads to atmospheric chemistry dominated by ions and atoms. These conditions inhibit day-t…

The trans-Neptunian object (119951) 2002 KX14 revealed via multiple stellar occultations Open

J. L. Rizos, J. L. Ortiz, F. L. Rommel, B. Sicardy, Nelson Morales , et al. · 2025

Context. Trans-Neptunian objects (TNOs) are icy bodies located in the outer solar system that offer key insights into the primordial conditions of our planetary system. The stellar occultation technique has proven to be an essential tool f…

Transit-timing variations in the AU Mic system observed with CHEOPS Open

Ádám Boldog, Gy. M. Szabó, L. Kriskovics, L. Borsato, D. Gandolfi , et al. · 2025

AU Mic is a very active M dwarf with an edge-on debris disk and two transiting sub-Neptunes with a possible third planetary companion. The two transiting planets exhibit significant transit-timing variations (TTVs) that are caused by the g…

A possible misaligned orbit for the young planet AU Mic c Open

Haochuan Yu, Z. Garai, M. Cretignier, Gy. M. Szabó, S. Aigrain , et al. · 2024

The AU Microscopii planetary system is only 24 Myr old, and its geometry may provide clues about the early dynamical history of planetary systems. Here, we present the first measurement of the Rossiter–McLaughlin effect for the warm sub-Ne…

Architecture of TOI-561 planetary system Open

G. Piotto, T. Zingales, L. Borsato, J. A. Egger, A. C. M. Correia , et al. · 2024

We present new observations from CHEOPS (CHaracterising ExOPlanet Satellite) and TESS (Transiting Exoplanet Survey Satellite) to clarify the architecture of the planetary system hosted by the old Galactic thick disc star TOI-561. Our globa…

A close outer companion to the ultra-hot Jupiter TOI-2109 b? Open

J. -V. Harre, A. M. S. Smith, S. C. C. Barros, V. Singh, J. Korth , et al. · 2024

Hot Jupiters with close-by planetary companions are rare, with only a handful of them having been discovered so far. This could be due to their suggested dynamical histories, leading to the possible ejection of other planets. TOI-2109 b is…

Architecture of TOI-561 planetary system Open

G. Piotto, T. Zingales, L. Borsato, J. A. Egger, A. C. M. Correia , et al. · 2024

We present new observations from CHEOPS and TESS to clarify the architecture of the planetary system hosted by the old Galactic thick disk star TOI-561. Our global analysis, which also includes previously published photometric and radial v…

The CHEOPS view on the climate of WASP-3 b Open

G. Scandariato, L. Carone, P. E. Cubillos, P. F. L. Maxted, T. Zingales , et al. · 2024

Hot Jupiters are giant planets subject to intense stellar radiation. The physical and chemical properties of their atmosphere makes them the most amenable targets for the atmospheric characterization. In this paper we analyze the photometr…

Characterisation of the warm-Jupiter TOI-1130 system with CHEOPS and a photo-dynamical approach Open

L. Borsato, David Degen, A. Leleu, M. J. Hooton, J. A. Egger , et al. · 2024

Context. Among the thousands of exoplanets discovered to date, approximately a few hundred gas giants on short-period orbits are classified as ‘lonely’ and only a few are in a multi-planet system with a smaller companion on a close orbit. …

Characterisation of the warm-Jupiter TOI-1130 system with CHEOPS and a photo-dynamical approach Open

L. Borsato, David Degen, A. Leleu, M. J. Hooton, J. A. Egger , et al. · 2024

Context. Among the thousands of exoplanets discovered to date, approximately a few hundred gas giants on short-period orbits are classified as ‘lonely’ and only a few are in a multi-planet system with a smaller companion on a close orbit. …

Unveiling the internal structure and formation history of the three planets transiting HIP 29442 (TOI-469) with CHEOPS Open

J. A. Egger, H. P. Osborn, Daria Kubyshkina, C. Mordasini, Y. Alibert , et al. · 2024

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-…

Photo-dynamical characterisation of the TOI-178 resonant chain Open

A. Leleu, J. -B. Delisle, L. Delrez, Edward M. Bryant, A. Brandeker , et al. · 2024

Context . The TOI-178 system consists of a nearby, late-K-dwarf with six transiting planets in the super-Earth to mini-Neptune regime, with radii ranging from to 2.9 R ⊕ and orbital periods between 1.9 and 20.7 days. All the planets, but t…

HR 10 as seen by CHEOPS and TESS. Revealing delta Scuti pulsations, granulation-like signal and hint for transients Open

Sébastien Salmon, V. Van Grootel, S. Sulis, Gy. M. Szabó, A. Brandeker , et al. · 2024

HR 10 has only recently been identified as a binary system. Previously thought to be an A-type shell star, it appears that both components are fast-rotating A-type stars, each presenting a circumstellar envelope. Although showing complex p…

HIP 41378 observed by CHEOPS: Where is planet d? Open

S. Sulis, L. Borsato, S. Grouffal, H. P. Osborn, A. Santerne , et al. · 2024

HIP 41378 d is a long-period planet that has only been observed to transit twice, three years apart, with K2. According to stability considerations and a partial detection of the Rossiter–McLaughlin effect, P d = 278.36 d has been determin…

The phase curve of the ultra-hot Jupiter WASP-167b as seen by TESS Open

Szilárd Kálmán, A. Derekas, Sz. Csizmadia, András Pál, R. Szabó , et al. · 2024

Context . Ultra-hot Jupiters (UHJs) orbiting pulsating A/F stars represent an important subset of the exoplanetary demographic. They are excellent candidates for the study of exoplanetary atmospheres, and are astrophysical laboratories for…

Characterisation of the TOI-421 planetary system using CHEOPS, TESS, and archival radial velocity data Open

A. Krenn, Daria Kubyshkina, L. Fossati, J. A. Egger, A. Bonfanti , et al. · 2024

The TOI-421 planetary system contains two sub-Neptune-type planets and is a prime target to study the formation and evolution of planets and their atmospheres. The inner planet is especially interesting as the existence of a hydrogen-domin…

Characterisation of the TOI-421 planetary system using CHEOPS, TESS, and archival radial velocity data Open

A. Krenn, Daria Kubyshkina, L. Fossati, J. A. Egger, A. Bonfanti , et al. · 2024

Context . The TOI-421 planetary system contains two sub-Neptune-type planets ( P b ~ 5.2 days, T eq , b ~ 900 K, and P c ~ 16.1 days, T eq,c ~ 650 K) and is a prime target to study the formation and evolution of planets and their atmospher…

Precise characterisation of HD 15337 with CHEOPS: A laboratory for planet formation and evolution Open

Nelson Augusto Rosário, O. D. S. Demangeon, S. C. C. Barros, D. Gandolfi, J. A. Egger , et al. · 2024

Context . The HD 15337 (TIC 120896927, TOI-402) system was observed by the Transiting Exoplanet Survey Satellite (TESS), revealing the presence of two short-period planets situated on opposite sides of the radius gap. This offers an excell…

Asymmetry in the atmosphere of the ultra-hot Jupiter WASP-76 b Open

O. D. S. Demangeon, Patricio E. Cubillos, V. Singh, T. G. Wilson, L. Carone , et al. · 2024

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 signatur…

Detailed cool star flare morphology with CHEOPS and TESS Open

G. Bruno, I. Pagano, G. Scandariato, H.-G. Florén, A. Brandeker , et al. · 2024

Context. White-light stellar flares are proxies for some of the most energetic types of flares, but their triggering mechanism is still poorly understood. As they are associated with strong X and ultraviolet emission, their study is partic…

The tidal deformation and atmosphere of WASP-12 b from its phase curve Open

B. Akinsanmi, S. C. C. Barros, M. Lendl, L. Carone, Patricio E. Cubillos , et al. · 2024

Context . Ultra-hot Jupiters present a unique opportunity to understand the physics and chemistry of planets, their atmospheres, and interiors at extreme conditions. WASP-12 b stands out as an archetype of this class of exoplanets, with a …

The tidal deformation and atmosphere of WASP-12b from its phase curve Open

B. Akinsanmi, S. C. C. Barros, M. Lendl, L. Carone, P. E. Cubillos , et al. · 2024

Ultra-hot Jupiters present a unique opportunity to understand the physics and chemistry of planets at extreme conditions. WASP-12b stands out as an archetype of this class of exoplanets. We performed comprehensive analyses of the transits,…

The EBLM Project– XI. Mass, radius, and effective temperature measurements for 23 M-dwarf companions to solar-type stars observed with <i>CHEOPS</i> Open

M I Swayne, P. F. L. Maxted, A. H. M. J. Triaud, S. G. Sousa, A. Deline , et al. · 2024

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 exopla…

Constraining the reflective properties of WASP-178 b using CHEOPS photometry Open

I. Pagano, G. Scandariato, V. Singh, M. Lendl, D. Queloz , et al. · 2024

Multiwavelength photometry of the secondary eclipses of extrasolar planets is able to disentangle the reflected and thermally emitted light radiated from the planetary dayside. This leads to the measurement of the planetary geometric albed…

Planets observed with CHEOPS Open

M. Fridlund, Iskra Georgieva, A. Bonfanti, Y. Alibert, C. M. Persson , et al. · 2024

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 hi…

The EBLM Project XI. Mass, radius and effective temperature measurements for 23 M-dwarf companions to solar-type stars observed with CHEOPS Open

M I Swayne, P. F. L. Maxted, A. H. M. J. Triaud, S. G. Sousa, A. Deline , et al. · 2023

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 exop…

Characterising TOI-732 b and c: New insights into the M-dwarf radius and density valley Open

A. Bonfanti, Madison Brady, T. G. Wilson, J. Venturini, J. A. Egger , et al. · 2023

TOI-732 is an M dwarf hosting two transiting planets that are located on the two opposite sides of the radius valley. By doubling the number of available space-based observations and increasing the number of radial velocity (RV) measuremen…

Constraining the reflective properties of WASP-178 b using CHEOPS photometry Open

I. Pagano, G. Scandariato, V. Singh, M. Lendl, D. Queloz , et al. · 2023

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 geometri…

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