B. Sicardy
A5022040938- Astro and Planetary Science
- Planetary Science and Exploration
- Stellar, planetary, and galactic studies
- Isotope Analysis in Ecology
- Astrophysics and Star Formation Studies
- Solar and Space Plasma Dynamics
- Space Exploration and Technology
- Atmospheric Ozone and Climate
- Geology and Paleoclimatology Research
- Geomagnetism and Paleomagnetism Studies
- Space Satellite Systems and Control
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Historical Astronomy and Related Studies
- Astronomy and Astrophysical Research
- Ionosphere and magnetosphere dynamics
- Geophysics and Gravity Measurements
- Scientific Research and Discoveries
- History and Developments in Astronomy
- Geological and Geochemical Analysis
- Quantum chaos and dynamical systems
- Spacecraft and Cryogenic Technologies
- Laser-induced spectroscopy and plasma
- Astronomical and nuclear sciences
- Methane Hydrates and Related Phenomena
Observatoire de Paris
2016-2025
Sorbonne Université
2016-2025
Délégation Paris 7
2016-2025
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2016-2025
Université Paris Cité
2016-2025
Centre National de la Recherche Scientifique
2016-2025
Université Paris Sciences et Lettres
2016-2025
Sorbonne Paris Cité
2013-2025
Institut de Mécanique Céleste et de Calcul des Éphémérides
2024-2025
Université de Lille
2025
Voyager 2 images of Neptune reveal a windy planet characterized by bright clouds methane ice suspended in an exceptionally clear atmosphere above lower deck hydrogen sulfide or ammonia ices. Neptune's is dominated large anticyclonic storm system that has been named the Great Dark Spot (GDS). About same size as Earth extent, GDS bears both many similarities and some differences to Red Jupiter. zonal wind profile remarkably similar Uranus. three major rings at radii 42,000, 53,000, 63,000...
Abstract The physical and orbital parameters of trans-Neptunian objects provide valuable information about the solar system’s formation evolution. In particular, characterization binaries provides insights into mechanisms that may be playing a role at such large distances from Sun. Studies show two distinct populations, (38628) Huya occupies an intermediate position between unequal-sized those with components roughly equal sizes. this work, we predicted observed three stellar occultation...
Jupiter Trojans preserve primitive formation characteristics owing to their collisionless, stable orbits. Determination of shapes and size-frequency distribution helps constrain the collisional evolution parent population, which also originated Kuiper Belt. We started a programme find precise sizes/shapes for Trojans, combining stellar occultations Database Asteroid Models from Inversion Techniques (DAMIT) three-dimensional shape models. report results Diomedes, by fitting its unit...
ABSTRACT We present results from a multi-chord Pluto stellar occultation observed on 2015 June 29 New Zealand and Australia. This occurred only two weeks before the NASA Horizons flyby of system serves as useful comparison between ground-based space results. find that Pluto's atmosphere is still expanding, with significant pressure increase 5 ± 2% since 2013 factor almost three 1988. trend rules out, today, an atmospheric collapse associated recession Sun. A central flash, rare occurrence,...
Quaoar is a classical Trans-Neptunian Object (TNO) with an area equivalent diameter of 1,100 km and orbital semi-major axis 43.3 astronomical units. Based on stellar occultations observed between 2018 2021, inhomogeneous ring (Q1R, Quaoar's first ring) was detected around this body. Aims. A new occultation by August 9th, 2022 aiming to improve shape models the physical parameters Q1R while searching for additional material Methods. The provided nine effective chords across Quaoar, pinning...
Comets offer valuable insights into the early Solar System's conditions and processes. Stellar occultations enable detailed study of cometary nuclei typically hidden by their coma. Observing star's light passing through coma helps infer dust's optical depth near nucleus determine dust opacity detection limits. 29P/Schwassmann-Wachmann 1, a Centaur with diameter approximately 60 km, lies in region transitioning from Centaurs to Jupiter-family comets. Our presents first-ever observed...
Obtained images from the Cassini spacecraft have unveiled several small satellites in vicinity of Mimas’ orbit: Aegaeon, Methone and Anthe. Anthe are situated within arcs material, while Aegaeon orbits an arc near inner edge Saturn’s G ring. The presence these moons is consistent with their confinement by corotation eccentric resonance (CER) Mimas. captured 7 : 6 mean motion Mimas, are, respectively, outer 14 15 10 11 resonances Here, we estimate probabilities capturing into respective CERs...
A recent high-angular resolution imaging survey of 42 large main belt asteroids, with the SPHERE/ZIMPOL instrument VLT, has provided shape models unprecedented kilometre accuracy. The aim this paper is to determine equilibrium figures these asteroids from their models, in order define a size limit between dwarf planets and small bodies. Therefore, we quantify deviation homogeneous hydrostatic equilibria (Maclaurin Jacobi ellipsoids) using spherical harmonic analysis minimization criterion...
In 2013, a stellar occultation revealed the presence of ring system around Centaur Chariklo, marking first discovery such feature on small body. Subsequent observations indicated that main exhibits not only radial density variations but also changes in width depending longitude. this study, we propose method to determine longitude (within an inertial reference frame) and orbital radius each point detected during occultations. addition, provide descriptive analysis ring’s identify combination...
Spectra from Cassini's Visual and Infrared Mapping Spectrometer reveal that the horizontal structure, height, optical depth of Titan's clouds are highly dynamic. Vigorous cloud centers seen to rise middle upper troposphere within 30 minutes dissipate next hour. Their development indicates evolve convectively; through rain; and, over several hours, waft downwind achieve their great longitude extents. These other characteristics suggest temperate originate circulation-induced convergence, in...
Observations of Saturn's ring system with the Hubble Space Telescope during 10 August 1995 Earth crossing and 17 to 21 November solar indicate that F dominates their apparent edge-on thickness 1.2 1.5 kilometers. The is slightly inclined respect A ring, which may explain approximately 50-minute difference in times for east west ansae August. Prometheus lags its predicted position by about 19 degrees longitude. faint G neutral or reddish color confined a radial range 2.72 2.85 Saturn radii....
<i>Context. <i/>Pluto possesses a thin atmosphere, primarily composed of nitrogen, in which the detection methane has been reported.<i>Aims. <i/>The goal is to constrain essential but so far unknown parameters Pluto's such as surface pressure, lower atmosphere thermal stucture, and mixing ratio.<i>Methods. <i/>We use high-resolution spectroscopic observations gaseous novel analysis occultation lightcurves.<i>Results. show that (i) pressure currently 6.5–24 <i>μ<i/>bar range, (ii) ratio...
We present results derived from the first multi-chord stellar occultations by transneptunian object (50000) Quaoar, observed on 2011 May 4 and 2012 February 17, a single-chord occultation October 15. If timing of five chords obtained in were correct, then Quaoar would possess topographic features (crater or mountain) that be too large for body this mass. An alternative model consists applying time shifts to some account possible errors. Satisfactory elliptical fits are possible, yielding an...