B. Akinsanmi
A5013803351- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Spacecraft Design and Technology
- Engineering and Test Systems
- History and Developments in Astronomy
- Spectroscopy and Chemometric Analyses
- Planetary Science and Exploration
- Calibration and Measurement Techniques
- Marine and environmental studies
- Adaptive optics and wavefront sensing
- SAS software applications and methods
- CCD and CMOS Imaging Sensors
University of Geneva
2021-2024
Universidade do Porto
2017-2022
Institute of Astrophysics and Space Sciences
2017-2022
National Space Research and Development Agency
2017-2020
Context. Measurements of the occultation an exoplanet at visible wavelengths allow us to determine reflective properties a planetary atmosphere. The observed depth can be translated into geometric albedo. This in turn aids characterising structure and composition atmosphere by providing additional information on wavelength-dependent qualities aerosols Aims. Our aim is provide precise measurement albedo gas giant HD 189733b measuring broad optical bandpass CHEOPS (350–1100 nm). Methods. We...
Context . Since the discovery of first exoplanet almost three decades ago, number known exoplanets has increased dramatically. By beginning 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 monitor transiting orbiting bright stars. In September 2023, CHEOPS completed its nominal mission duration 3.5 yr and remains excellent operational conditions. As...
WASP-103b is the exoplanet with highest expected deformation signature in its transit light curve and one of shortest spiral-in times. Measuring tidal planet would allow us to estimate second degree fluid Love number gain insight into planet's internal structure. Moreover, measuring decay timescale stellar quality factor, which key constraining physics. We obtained 12 curves CHEOPS this extreme system. modelled high-precision together systematic instrumental noise using multi-dimensional...
Abstract We present a near-infrared transmission spectrum of the long-period ( P = 542 days), temperate T eq 294 K) giant planet HIP 41378 f obtained with Wide-Field Camera 3 instrument aboard Hubble Space Telescope (HST). With measured mass 12 ± M ⊕ and radius 9.2 0.1 R , has an extremely low bulk density (0.09 0.02 g cm −3 ). measure transit depth median precision 84 ppm in 30 spectrophotometric channels uniformly sized widths 0.018 μ m. Within this level precision, shows no evidence...
Hot Jupiters generally do not have nearby planet companions, as they may cleared out other planets during their inward migration from more distant orbits. This gives evidence that hot often migrate via high-eccentricity due to dynamical interactions between rather than dynamically cool mechanisms through the protoplanetary disk. Here we further refine unique system of WASP-132 by characterizing mass recently validated 1.0-day period super-Earth WASP-132c (TOI-822.02), interior 7.1-day...
The current and upcoming high precision photometric surveys such as TESS, CHEOPS, PLATO will provide the community with thousands of new exoplanet candidates. As a consequence, presence correlation is crucial in selecting targets lowest RV jitter for efficient follow-up exoplanetary Studies this type are also to design optimized observational strategies mitigate when searching Earth-mass exoplanets. Our goal assess between high-precision variability measurements over different time scales....
Context. Tidal orbital decay is suspected to occur for hot Jupiters in particular, with the only observationally confirmed case of this being WASP-12b. By examining effect, information on properties host star can be obtained using so-called stellar modified tidal quality factor Q * ′ , which describes efficiency kinetic energy planet dissipated within star. This provide about interior Aims. In study, we aim improve constraints KELT-9, KELT-16, and WASP-4 systems order find evidence or...
The planetary system around the naked-eye star v 2 Lupi (HD 136352; TOI-2011) is composed of three exoplanets with masses 4.7, 11.2, and 8.6 Earth ( M ⊕ ). TESS CHEOPS missions revealed that all planets are transiting have radii straddling radius gap separating volatile-rich volatile-poor super-earths. Only a partial transit planet d had been covered so we re-observed an inferior conjunction long-period exoplanet Lup space telescope. We confirmed its nature by covering whole 9.1 h for first...
CONTEXT. It is theoretically possible for rings to have formed around extrasolar planets in a similar way that which they the giant our solar system. However, no such been detected date. AIMS: We aim test possibility of detecting exoplanets by investigating photometric and spectroscopic ring signatures high-precision transit signals. METHODS: The signals ringed planet expected show deviations from spherical planet. used these quantify detectability rings. present SOAP3.0 numerical tool...
Context . Ultra-hot Jupiters present a unique opportunity to understand the physics and chemistry of planets, their atmospheres, interiors at extreme conditions. WASP-12 b stands out as an archetype this class exoplanets, with close-in orbit around its star that results in intense stellar irradiation tidal effects. Aims The goals are measure planet’s deformation, atmospheric properties, also refine orbital decay rate. Methods We performed comprehensive analyses transits, occultations, phase...
Transmission spectroscopy is a proven technique for studying transiting exoplanet’s atmosphere. However, stellar surface inhomogeneities – spots and faculae alter the observed transmission spectra: contamination effect. The variable nature of activity also makes it difficult to stitch together multi-epoch observations evaluate any potential variability in This paper introduces SAGE , tool that corrects time-dependent impact on spectra. It uses pixelation approach model with faculae, while...
The presence of rings around a transiting planet can cause its radius to be overestimated and lead an underestimation density if the mass is known. We employ Bayesian framework show that anomalously low ($\sim$0.09 g cm${^{-3}}$) long-period HIP$\,$41378$\,f$ might due opaque circum-planetary rings. Given our adopted model priors data from K2 mission, we find statistical evidence for ringed scenario comparable planet-only scenario. solution suggests larger planetary...
Abstract Moons orbiting exoplanets (“exomoons”) may hold clues about planet formation, migration, and habitability. In this work, we investigate the plausibility of exomoons temperate ( T eq = 294 K) giant R 9.2 ⊕ ) HIP 41378 f, which has been shown to have a low apparent bulk density 0.09 g cm −3 flat near-infrared transmission spectrum, hinting that it possess circumplanetary rings. Given planet’s long orbital period P ≈ 1.5 yr), suggested also host large exomoon. Here, analyze stability...
Short-period planets suffer from extreme tidal forces their parent stars causing them to deform and attain non-spherical shapes. The planet shapes, modeled here as triaxial ellipsoids, can have an impact on the observed transit light curves planetary parameters derived. We investigate detectability of deformation in short-period instrumental precision needed. show how detection curve allows us obtain observational estimate second fluid Love number which gives valuable insight about planet's...
Detailed understanding of stellar physics is essential towards a robust determination properties (e.g. radius, mass, and age). Among the vital input used in modelling solar-type stars which remain poorly constrained, initial helium abundance. To this end, when constructing model grids, abundance estimated either (i) by using semi-empirical helium-to-heavy element enrichment ratio, (${\Delta Y}/{\Delta Z}$), anchored to standard Big Bang Nucleosynthesis value or (ii) setting as free variable....
Context . Occultations are windows of opportunity to indirectly peek into the dayside atmosphere exoplanets. High-precision transit events provide information on spin-orbit alignment exoplanets around fast-rotating hosts. Aims We aim precisely measure planetary radius and geometric albedo ultra-hot Jupiter (UHJ) KELT-20 b along with system. Methods obtained optical high-precision transits occultations using CHEOPS observations in conjunction simultaneous TESS observations. interpreted...
We analyse spectroscopic and photometric transits of the hot Jupiters WASP-52b HAT-P30b obtained with ESPRESSO, Eulercam NGTS for both targets, additional TESS data HAT-P-30. Our goal is to update system parameters refine our knowledge host star surfaces. For WASP-52, companion planet has occulted starspots in past, as such aim was use reloaded Rossiter-McLaughlin technique directly probe its starspot properties. Unfortunately, we find no evidence occultations datasets herein. Additionally,...
While the sample of confirmed exoplanets continues to increase, population transiting around early-type stars is still limited. These planets allow us investigate planet properties and formation pathways over a wide range stellar masses study impact high irradiation on hot Jupiters orbiting such stars. We report discovery TOI-615b, TOI-622b, TOI-2641b, three Saturn-mass main sequence, F-type The were identified by Transiting Exoplanet Survey Satellite (TESS) with complementary ground-based...
With the continuous improvement in precision of exoplanet observations, it has become feasible to probe for subtle effects that can enable a more comprehensive characterization exoplanets. A notable example is tidal deformation ultra-hot Jupiters by their host stars, whose detection provide valuable insights into planetary interior structure. In this work we extend previous research on modeling transit light curves proposing straightforward approach account phase curve observations. The...
CHEOPS is a space telescope specifically designed to monitor transiting exoplanets orbiting bright stars. In September 2023, completed its nominal mission and remains in excellent operational conditions. The has been extended until the end of 2026. Scientific instrumental data have collected throughout in-orbit commissioning operations, enabling comprehensive analysis mission's performance. this article, we present results with twofold goal. First, aim inform scientific community about...
The Rossiter-McLaughlin (RM) effect is the radial velocity signal generated when an object transits a rotating star. Stars rotate differentially and this affects shape amplitude of signal, on level that can no longer be ignored with precise spectrographs. Highly misaligned planets provide unique opportunity to probe stellar differential rotation via RM effect, as they cross several latitudes. In sense, WASP-7, its hot Jupiter projected misalignment \sim 90{\deg}, one most promising targets....
Rapid planetary rotation can cause the equilibrium shape of a planet to be oblate. While oblateness has mostly been probed by examining subtle ingress and egress features in photometric transit light curves, we investigate effect on spectroscopic Rossiter-McLaughlin (RM) signals. We found that giant planet, with planet-to-star radius ratio 0.15 Saturn-like 0.098, signatures amplitudes up 1.1 ms$^{-1}$ which is detectable high-precision spectrographs such as ESPRESSO. also signals are...
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 this class exoplanets. We performed comprehensive analyses transits, occultations, phase curves by combining new CHEOPS observations with previous TESS Spitzer data measure planet's tidal deformation, atmospheric properties, orbital decay rate. The planet was modeled triaxial ellipsoid parameterized second-order fluid Love number,...
Hot Jupiters generally do not have nearby planet companions, as they may cleared out other planets during their inward migration from more distant orbits. This gives evidence that hot often migrate via high-eccentricity due to dynamical interactions between rather than dynamically cool mechanisms through the protoplanetary disk. Here we further refine unique system of WASP-132 by characterizing mass recently validated 1.0-day period super-Earth WASP-132c (TOI-822.02) interior 7.1-day Jupiter...