A. Collier Cameron
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View article: WASP-12, shrouded in mystery or just cold gas?
WASP-12, shrouded in mystery or just cold gas? Open
Observations of the planet-hosting star WASP-12 show a distinctive depression in the Mg ii and Ca ii resonance lines. This has been interpreted as a marker of atmospheric loss from the close-in hot Jupiter WASP-12b and the resulting format…
View article: HARPS-N, TESS, and CHEOPS discover a transiting sub-Neptune and two outer companions around the bright solar analogue HD 85426
HARPS-N, TESS, and CHEOPS discover a transiting sub-Neptune and two outer companions around the bright solar analogue HD 85426 Open
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…
View article: An ultra-short period super-Earth and sub-Neptune spanning the Radius Valley orbiting the kinematic thick disc star TOI-2345
An ultra-short period super-Earth and sub-Neptune spanning the Radius Valley orbiting the kinematic thick disc star TOI-2345 Open
A crucial chemical link between stars and their orbiting exoplanets is thought to exist. If universal, this connection could affect the formation and evolution of all planets. Therefore, this potential vital link needs testing by character…
View article: An Ultra-Short Period Super-Earth and Sub-Neptune Spanning the Radius Valley Orbiting the Kinematic Thick Disk Star TOI-2345
An Ultra-Short Period Super-Earth and Sub-Neptune Spanning the Radius Valley Orbiting the Kinematic Thick Disk Star TOI-2345 Open
A crucial chemical link between stars and their orbiting exoplanets is thought to exist. If universal, this connection could affect the formation and evolution of all planets. Therefore, this potential vital link needs testing by character…
View article: The mass of the exo-Venus Gliese 12 b, as revealed by HARPS-N, ESPRESSO, and CARMENES
The mass of the exo-Venus Gliese 12 b, as revealed by HARPS-N, ESPRESSO, and CARMENES Open
Small temperate planets are prime targets for exoplanet studies due to their possible similarities with the rocky planets in the Solar system. M dwarfs are promising hosts since the planetary signals are within our current detection capabi…
View article: Improved characterization of the TOI-2141 system: A dense sub-Neptune with non-transiting inner and outer companions
Improved characterization of the TOI-2141 system: A dense sub-Neptune with non-transiting inner and outer companions Open
Aims. We aim to refine the fundamental parameters of the TOI-2141 planetary system, which includes a transiting sub-Neptune orbiting a Sun-like star on a relatively long orbit of 18.26 days, by combining new photometric and spectroscopic o…
View article: Transit timing variations in HIP 41378: CHEOPS and TESS confirm a non-transiting sixth planet in the system
Transit timing variations in HIP 41378: CHEOPS and TESS confirm a non-transiting sixth planet in the system Open
In multiple-planet systems, gravitational interactions of exoplanets could lead to transit timing variations (TTVs), whose amplitude becomes significantly enhanced when planets are in or near mean-motion resonances (MMRs), making them more…
View article: Granulation on a quiet K dwarf: HD 166620 I. Spectral signatures as a function of line-formation temperature
Granulation on a quiet K dwarf: HD 166620 I. Spectral signatures as a function of line-formation temperature Open
As radial velocity (RV) spectrographs reach unprecedented precision and stability below 1 m s$^{-1}$, the challenge of granulation in the context of exoplanet detection has intensified. Despite promising advancements in post-processing too…
View article: Discovery of a multi-planet system orbiting the aged Sun-like star HD 224018
Discovery of a multi-planet system orbiting the aged Sun-like star HD 224018 Open
Context . Exoplanetary systems show a large diversity of architectures and planet types. Among the increasing number of exodemographics studies, those exploring correlations between the presence of close-in small planets and cold Jupiters …
View article: A four-planet system orbiting the old thick disk star TOI-1203
A four-planet system orbiting the old thick disk star TOI-1203 Open
TOI-1203 is a bright (V=8.6) G3 V star known to host a transiting warm sub-Neptune on a 25.5 d orbit. Here we report on an intensive high-precision radial velocity and photometric follow-up campaign carried out with the HARPS spectrograph …
View article: Sensitivity of spectral lines to granulation: The Sun
Sensitivity of spectral lines to granulation: The Sun Open
The intrinsic variability of stars, due to acoustic oscillations, surface granulation, and magnetic activity, introduces radial velocity (RV) jitter in spectral lines, obscuring true planetary signals and hindering the detection of Earth-l…
View article: Improved characterization of the TOI-2141 system: a dense sub-Neptune with non-transiting inner and outer companions
Improved characterization of the TOI-2141 system: a dense sub-Neptune with non-transiting inner and outer companions Open
We aim to refine the fundamental parameters of the TOI-2141 planetary system, which includes a transiting sub-Neptune orbiting a Sun-like star in a relatively long orbit of 18.26 days, by combining new photometric and spectroscopic observa…
View article: Using Doppler imaging to model stellar activity and search for planets around Sun-like stars
Using Doppler imaging to model stellar activity and search for planets around Sun-like stars Open
Doppler imaging (DI) is a well-established technique to map a physical field at a stellar surface from a time series of high-resolution spectra. In this proof-of-concept study, we aim to show that traditional DI algorithms, originally desi…
View article: The CHEOPS view of HD 95338b: Refined transit parameters, and a search for exomoons
The CHEOPS view of HD 95338b: Refined transit parameters, and a search for exomoons Open
Context . Despite the ever-increasing number of known exoplanets, no uncontested detections have been made of their satellites, known as exomoons. Aims . The quest to find exomoons is at the forefront of exoplanetary sciences. Certain spac…
View article: Measuring the Sun’s radial velocity variability due to supergranulation over a magnetic cycle.
Measuring the Sun’s radial velocity variability due to supergranulation over a magnetic cycle. Open
In recent years, supergranulation has emerged as one of the biggest challenges for the detection of Earth-twins in radial velocity planet searches. We used eight years of Sun-as-a-star radial velocity observations from HARPS-N to measure t…
View article: Geometric albedo of WASP-12 b and WASP-76 b in the CHEOPS and TESS bandpasses (<i>Corrigendum</i>)
Geometric albedo of WASP-12 b and WASP-76 b in the CHEOPS and TESS bandpasses (<i>Corrigendum</i>) Open
International audience
View article: Measuring the Suns radial velocity variability due to supergranulation over a magnetic cycle
Measuring the Suns radial velocity variability due to supergranulation over a magnetic cycle Open
In recent years supergranulation has emerged as one of the biggest challenges for the detection of Earth-twins in radial velocity planet searches. We used eight years of Sun-as-a-star radial velocity observations from HARPS-N to measure th…
View article: The KELT-7b atmospheric thermal-inversion conundrum revisited with CHEOPS, TESS, and additional data
The KELT-7b atmospheric thermal-inversion conundrum revisited with CHEOPS, TESS, and additional data Open
Context . Early theoretical works suggested that ultrahot Jupiters have inverted temperature-pressure (T–P) profiles in the presence of optical absorbers, such as TiO and VO. Recently, an inverted T–P profile of KELT-7b was detected, in ag…
View article: The KELT-7b atmospheric thermal-inversion conundrum revisited with CHEOPS, TESS, and additional data
The KELT-7b atmospheric thermal-inversion conundrum revisited with CHEOPS, TESS, and additional data Open
Ultrahot Jupiters are predicted to show inverted temperature-pressure (T-P) profiles in the presence of optical absorbers such as TiO and VO. An inverted T-P profile of KELT-7b was recently detected, in line with these predictions, but suc…
View article: The mass of the exo-Venus Gliese 12 b, as revealed by HARPS-N, ESPRESSO, and CARMENES
The mass of the exo-Venus Gliese 12 b, as revealed by HARPS-N, ESPRESSO, and CARMENES Open
Small temperate planets are prime targets for exoplanet studies due to their possible similarities with the rocky planets in the Solar System. M dwarfs are promising hosts since the planetary signals are within our current detection capabi…
View article: Dark skies of the slightly eccentric WASP-18 b from its optical-to-infrared dayside emission
Dark skies of the slightly eccentric WASP-18 b from its optical-to-infrared dayside emission Open
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…
View article: A Swarm of WASP Planets: Nine Giant Planets Identified by the WASP Survey
A Swarm of WASP Planets: Nine Giant Planets Identified by the WASP Survey Open
The Wide Angle Search for Planets (WASP) survey provided some of the first transiting hot Jupiter candidates. With the addition of the Transiting Exoplanet Survey Satellite (TESS), many WASP planet candidates have now been revisited and gi…
View article: A Swarm of WASP Planets: Nine giant planets identified by the WASP survey
A Swarm of WASP Planets: Nine giant planets identified by the WASP survey Open
The Wide Angle Search for Planets (WASP) survey provided some of the first transiting hot Jupiter candidates. With the addition of the Transiting Exoplanet Survey Satellite (TESS), many WASP planet candidates have now been revisited and gi…
View article: Searching for hot water world candidates with CHEOPS
Searching for hot water world candidates with CHEOPS Open
Studying the composition of exoplanets is one of the most promising approaches to observationally constrain planet formation and evolution processes. However, this endeavour is complicated for small exoplanets by the fact that a wide range…
View article: A joint effort to discover and characterize two resonant mini-Neptunes around TOI-1803 with TESS, HARPS-N, and CHEOPS
A joint effort to discover and characterize two resonant mini-Neptunes around TOI-1803 with TESS, HARPS-N, and CHEOPS Open
Context. The discovery and characterization of mini-Neptunes hold a potentially crucial impact on planetary formation and evolution theories. Estimating their orbital parameters and atmospheric properties would provide valuable hints to im…
View article: Searching for Hot Water World Candidates with CHEOPS: Supplementary Material for TOI-238 b and TOI-1685 b (atmospheric evolution tracks)
Searching for Hot Water World Candidates with CHEOPS: Supplementary Material for TOI-238 b and TOI-1685 b (atmospheric evolution tracks) Open
This distribution includes the supplementary data for sections 3.1.5 and 3.2.4 of Egger et al., 2025 (accepted for publication in A&A; https://arxiv.org/pdf/2502.07887), namely, the atmospheric evolution tracks of TOI-238 b and TOI-1685 b,…
View article: In-depth characterization of the Kepler-10 three-planet system with HARPS-N radial velocities and Kepler transit timing variations
In-depth characterization of the Kepler-10 three-planet system with HARPS-N radial velocities and Kepler transit timing variations Open
The old G3V star Kepler-10 is known to host two transiting planets, the ultra-short-period super-Earth Kepler-10b ($P=0.837$ d; $R_{\rm p}=1.47~\rm R_\oplus$) and the long-period sub-Neptune Kepler-10c ($P=45.294$ d; $R_{\rm p}=2.35~\rm R_…
View article: Transit-timing variations in the AU Mic system observed with CHEOPS
Transit-timing variations in the AU Mic system observed with CHEOPS Open
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…
View article: Transit-timing variations in the AU Mic system observed with CHEOPS
Transit-timing variations in the AU Mic system observed with CHEOPS Open
Context . AU Mic is a very active M dwarf star with an edge-on debris disk and two known transiting sub-Neptunes with a possible third planetary companion. The two transiting planets exhibit significant transit-timing variations (TTVs) tha…
View article: CHEOPS observations confirm nodal precession in the WASP-33 system
CHEOPS observations confirm nodal precession in the WASP-33 system Open
Aims: We aim to observe the transits and occultations of WASP-33b, which orbits a rapidly-rotating $δ$ Scuti pulsator, with the goal of measuring the orbital obliquity via the gravity-darkening effect, and constraining the geometric albedo…