CHEOPS Archives

The radial gas temperature maps of planets from the 3D AFGKM ExoRad with a global temperature, Tglobal of 800K (left), 1600K (center) and 2400K (right) that orbit different host stars (top to bottom: A, G, M). The (Tgas, pgas)-maps gas are shown as equatorial slice plots. -- astro-ph.EP

AI - Data - Apps - Cybernetics, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Status Report

Accelerating Exoplanet Climate Modelling: A Machine Learning Approach To Complement 3D GCM Grid Simulations

by Keith CowingAugust 15, 2025August 15, 2025

With the development of ever-improving telescopes capable of observing exoplanet atmospheres in greater detail and number, there is a growing demand for enhanced 3D climate models to support and help […]

Accuracy of the retrieved oblateness parameter in the light curve which included red noise, for all eight σw noise levels. Squares in the input f–ϑ grid are coloured based on the accuracy of the fitted f: purple if the retrieved parameter is within 0.02 of the injected value, blue if it is within 0.04, orange when it is within 0.06, and red otherwise. Shading is present when no significant detection of oblateness is made (i.e. when there is no 3σ detection of f). -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release

Prospects Of Detecting Rotational Flatness Of Exoplanets From Space-based Photometry

by Keith CowingJuly 25, 2025July 25, 2025

In the era of photometry with space-based telescopes, such as CHEOPS (CHaracterizing ExOPlanets Satellite), JWST (James Webb Space Telescope), PLATO (PLAnetary Transits and Oscillations of stars), and ARIEL (Atmospheric Remote-sensing […]

Sensitivity maps for the four CHEOPS visits of HD 95338. The first row represents the best-fit box depth (i.e. moon radius) in the ∆T0–W space. The 3σ lower limit of the moon radius is shown in the second row, while the third and fourth rows represent the ∆BIC and ∆AIC values between a solution with and without a moon. The empty (blank) areas are values that are below a threshold of 0 R⊕ for the moon radius (first 2 rows) and a threshold of 2 for the ∆BIC and ∆AIC (last 2 rows). The grey squares (and corresponding dotted lines) show the position of the transit of HD 95338b in this parameter space for each visit. An underlying linear trend is assumed for each of the four visits. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

The CHEOPS View Of HD 95338b: Refined Transit Parameters, And A Search For Exomoons

by Keith CowingJuly 25, 2025July 25, 2025

Despite the ever-increasing number of known exoplanets, no uncontested detections have been made of their satellites, known as exomoons.

Phase-folded RVs from the best-fit informed RV model with GPs removed. Binned data shown by the large, purple points (10 bins). Phasefolded on the period of the planet (12.761421 d). -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Venus

The Mass Of The Exo-Venus Gliese 12 b, As Revealed By HARPS-N, ESPRESSO, And CARMENES

by Keith CowingJune 27, 2025September 18, 2025

Small temperate planets are prime targets for exoplanet studies due to their possible similarities with the rocky planets in the Solar System.

Overview of the CHEOPS operational chain. The ground segment components, MOC and SOC, are represented by coloured boxes. The orange arrows describe the weekly operations from reviewing and ingesting the observations requests to the uplink of the TCs. The grey arrows trace the Science and Housekeeping data flow, from raw, to stored processed data accessible to the community, as well as the orbit and pass time determination, crucial for the planning phase. Finally, the steps outlined in this paper are marked with a bold number corresponding to their respective section. astro-ph.IM

Exoplanets, -moons, -comets, Imaging & Spectroscopy, Missions & Hardware, Status Report

CHEOPS Ground Segment: Systems And Automation For Mission and Science Operations

by Keith CowingMay 15, 2025May 15, 2025

The CHEOPS, the first ESA small-class mission, has been performing photometric astronomical observations with a particular emphasis on exoplanetary science for the past five years.

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report

Updating the Ephemeris and Physical Properties of Five Long-period Transiting Exoplanets Using TESS and CHEOPS

by Keith CowingApril 3, 2025April 3, 2025

The transiting long-period exoplanets are the most interesting follow-up targets for the next-generation instruments, using the most sophisticated observational techniques.

The CHEOPS transit light curves of planet K2-266 d (top, orange) and K2-266 e (bottom, purple). For each planet, we show the corrected light curve and best-fit model (left) as well as the residuals (right). The data are plotted with respect to the linear ephemeris from Rodriguez et al. (2018). -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography

Towards High Precision Mass Measurements of Two Sub-Neptunes in the K2-266 Planetary System Through Transit Timing

by Keith CowingMarch 16, 2025

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 investigation.

Top: Transmission Spectroscopy showing extra absorption in the Na doublet’s core lines across different global abundances, measured in PPM. This plot compares three injected models, illustrating the presence or absence of TiO and VO. It features one example with error bars plus a main strand after several runs. In light blue, regions below 200 ppm are highlighted, indicating areas under the estimated error threshold coming from models without signals. Bottom: Three examples of Transmission Spectroscopy in PPM are presented. Black points represent data binned by a factor of 100, the light blue area denotes a 95% confidence interval, magenta highlights the core lines, and red dashed lines indicate the standard deviation of the continuum. Below these plots are normalised flux profiles centred on the core lines, with a dashed blue line marking the Na doublets. -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

A Closer Look at LTT 9779b: The ESPRESSO Endeavour to Pierce the Atmospheric Veil

by Keith CowingFebruary 3, 2025February 2, 2025

The proliferation of exoplanet discoveries in exotic environments like the Neptune desert challenges our understanding of planetary atmospheres under intense irradiation. The unexpected discovery of LTT9779 b, an ultra-hot Neptune […]

TESS aperture field around the target star TOI-1803. (Image generated with tpfplotter, Aller et al. (2020)). -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

A Joint Effort To Discover And Characterize Two Resonant Mini Neptunes Around TOI-1803 With TESS, HARPS-N And CHEOPS

by Keith CowingDecember 16, 2024December 16, 2024

We present the discovery of two mini Neptunes near a 2:1 orbital resonance configuration orbiting the K0 star TOI-1803. We describe their orbital architecture in detail and suggest some possible […]

Stability analysis of the TOI-561 planetary system. For fixed initial conditions (Table 2), the parameter space of the system is explored by varying the orbital period and the eccentricity of planet- 𝑓 . The step size is 0.25 day in the orbital period and 0.0025 in the eccentricity. For each initial condition, the system is integrated over 10 000 yr, and a stability indicator is calculated, which involved a frequency analysis of the mean longitude of the inner planet. The chaotic diffusion is measured by the variation in the main frequency. Red points correspond to highly unstable orbits, while blue points correspond to orbits that are likely to be stable on Gyr timescales. The black curve corresponds to 𝐾 = 1.88 m/s and the black dot shows the values of the best fit solution (Table 2). -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Architecture Of TOI-561 Planetary System

by Keith CowingOctober 27, 2024October 27, 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.

CHEOPS

Accelerating Exoplanet Climate Modelling: A Machine Learning Approach To Complement 3D GCM Grid Simulations

Prospects Of Detecting Rotational Flatness Of Exoplanets From Space-based Photometry

The CHEOPS View Of HD 95338b: Refined Transit Parameters, And A Search For Exomoons

The Mass Of The Exo-Venus Gliese 12 b, As Revealed By HARPS-N, ESPRESSO, And CARMENES

CHEOPS Ground Segment: Systems And Automation For Mission and Science Operations

Updating the Ephemeris and Physical Properties of Five Long-period Transiting Exoplanets Using TESS and CHEOPS

Towards High Precision Mass Measurements of Two Sub-Neptunes in the K2-266 Planetary System Through Transit Timing

A Closer Look at LTT 9779b: The ESPRESSO Endeavour to Pierce the Atmospheric Veil

A Joint Effort To Discover And Characterize Two Resonant Mini Neptunes Around TOI-1803 With TESS, HARPS-N And CHEOPS

Architecture Of TOI-561 Planetary System

Astrobiologist Dale Andersen’s Antarctic Field Report: 9 November 2026: Lake Untersee Basecamp Update

From Anoxic to Oxic Earth: Detectability of Atmospheric Biosignatures Across Stellar Hosts with ELT/ANDES

The Kinetic Basis of the Genetic Code

Power Density as a Universal Biosignature: An Application to the Stellivore Hypothesis

The Limits of Tidal Circularization and Atmospheric Escape for Mini-Neptunes and Super-Earths: The Case of TOI-2257 b