E. Lellouch
A5087028059- Astro and Planetary Science
- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Stellar, planetary, and galactic studies
- Space Exploration and Technology
- Astrophysics and Star Formation Studies
- Isotope Analysis in Ecology
- Solar and Space Plasma Dynamics
- Spacecraft and Cryogenic Technologies
- Spectroscopy and Laser Applications
- Astronomical Observations and Instrumentation
- Atmospheric and Environmental Gas Dynamics
- Scientific Research and Discoveries
- Nuclear Physics and Applications
- Astronomy and Astrophysical Research
- Geology and Paleoclimatology Research
- Ionosphere and magnetosphere dynamics
- Geophysics and Gravity Measurements
- Space Science and Extraterrestrial Life
- Gamma-ray bursts and supernovae
- Geomagnetism and Paleomagnetism Studies
- Calibration and Measurement Techniques
- High-pressure geophysics and materials
- Methane Hydrates and Related Phenomena
- Spacecraft Design and Technology
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2015-2024
Université Paris Cité
2015-2024
Sorbonne Paris Cité
2016-2024
Sorbonne Université
2015-2024
Université Paris Sciences et Lettres
2016-2024
Observatoire de Paris
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Délégation Paris 7
2015-2024
Université de Versailles Saint-Quentin-en-Yvelines
2015-2024
University of Central Florida
2020
Comet Hale-Bopp (C/1995 O1) was observed at wavelengths from 2.4 to 195 micrometers with the Infrared Space Observatory when comet about 2.9 astronomical units (AU) sun. The main volatiles that sublimated nucleus ices were water, carbon monoxide, and dioxide in a ratio (by number) of 10:6:2. These species are also constituents dense interstellar molecular clouds; this observation strengthens links between cometary material. Several broad emission features 7- 45-micrometer region suggest...
Temperatures obtained from early Cassini infrared observations of Titan show a stratopause at an altitude 310 kilometers (and 186 kelvin 15 degrees S). Stratospheric temperatures are coldest in the winter northern hemisphere, with zonal winds reaching 160 meters per second. The concentrations several stratospheric organic compounds enhanced mid- and high latitudes, strong may inhibit mixing between these latitudes rest Titan. Above south pole, stratosphere 4 to 5 cooler than equator. mole...
Heat transport and ice sublimation in comets are interrelated processes reflecting properties acquired at the time of formation during subsequent evolution. The Microwave Instrument on Rosetta Orbiter (MIRO) maps subsurface temperature comet 67P/Churyumov-Gerasimenko, 1.6 mm 0.5 wavelengths, spectra water vapor. total H2O production rate varied from 0.3 kg s(-1) early June 2014 to 1.2 late August showed periodic variations related nucleus rotation shape. Water outgassing was localized "neck"...
The vertical distribution of Titan's neutral atmosphere compounds is calculated from a new photochemical model extending 40 to 1432 km. This makes use many updated reaction rates, and the scheme for methane photolysis proposed by Mordaunt et al. [1993]. also includes realistic treatment dissociation N 2 , deposition water in meteoritic ablation, condensation processes. sensitivity results eddy diffusion coefficient profile investigated. Fitting thermospheric stratospheric abundance major...
Observations with the Short Wavelength Spectrometer (SWS) onboard Infrared Space Observatory (ISO) are used to determine D/H ratio in Jupiter's and Saturn's atmospheres. The is measured independently hydrogen (i.e. from HD/H2 ratio) methane (from CH3D/CH4). of HD R(2) R(3) rotational lines at 37.7 28.5 μm, H2 S(0) S(1) quadrupolar 17.1 28.2 band 7.7 CH3D 8.6 μm analyzed jointly, allowing a retrieval thermal profiles molecular abundances. On each planet, determinations CH4 give consistent...
We have developed a one‐dimensional, diurnally averaged, photochemical model for Jupiter's stratosphere that couples photodissociation, chemical kinetics, vertical diffusion, and radiative transport. The predictions regarding the abundances profiles of hydrocarbon compounds are compared with observations from Infrared Space Observatory (ISO) to better constrain atmospheric composition, define eddy diffusion coefficient profile, understand reaction schemes produce destroy observed...
The Atmospheric Chemistry Suite (ACS) package is an element of the Russian contribution to ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission. ACS consists three separate infrared spectrometers, sharing common mechanical, electrical, and thermal interfaces. This ensemble spectrometers has been designed developed in response mission objectives that specifically address requirement high sensitivity instruments enable unambiguous detection trace gases potential geophysical or biological...
Transneptunian objects (TNOs) are bodies populating the Kuiper Belt and they believed to retain most pristine least altered material of solar system. The Herschel Open Time Key Program entitled "TNOs Cool: A survey trans-Neptunian region" has been awarded 373 h investigate albedo, size distribution thermal properties TNOs Centaurs. Here we focus on brightest targets observed by both PACS SPIRE multiband photometers: dwarf planet Haumea, six (Huya, Orcus, Quaoar, Salacia, 2002 UX25, TC302),...
The D/H ratio in cometary water is believed to be an important indicator of the conditions under which icy planetesimals formed and can provide clues contribution comets delivery other volatiles Earth. Available measurements suggest that there isotopic diversity comet population. Herschel Space Observatory revealed ocean-like Jupiter-family 103P/Hartley 2, whereas most values measured Oort-cloud are twice as high ocean ratio. We present here a new measurement comet. HDO, H2O, lines were...
We analyze albedo data obtained using the Herschel Space Observatory that reveal existence of two distinct types surface among midsized trans-Neptunian objects. A color–albedo diagram shows large clusters objects, one redder and higher another darker more neutrally colored. Crucially, all objects in our sample located dynamically stable orbits within classical Kuiper Belt region beyond are confined to bright red group, implying a compositional link. Those believed have formed further from...
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,...
While small Neptune-like planets are among the most abundant exoplanets, our understanding of their atmospheric structure and dynamics remains sparse. In particular, many unknowns remain regarding way moist convection works in these atmospheres, where condensable species heavier than non-condensable background gas. it has been predicted that could cease above some threshold abundance species, this prediction is based on simple linear analysis relies strong assumptions saturation atmosphere....
Abstract The MAJIS (Moons And Jupiter Imaging Spectrometer) instrument on board the ESA JUICE (JUpiter ICy moon Explorer) mission is an imaging spectrometer operating in visible and near-infrared spectral range from 0.50 to 5.55 μm two channels with a boundary at 2.3 samplings for VISNIR IR better than 4 nm/band 7 nm/band, respectively. IFOV 150 μrad over total of 400 pixels. As already amply demonstrated by past present operative planetary space missions, this type can span wide scientific...