A5004162129- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Space Science and Extraterrestrial Life
- Marine and environmental studies
- Spectroscopy and Laser Applications
- Solar and Space Plasma Dynamics
- Scientific Research and Discoveries
- Spaceflight effects on biology
- Astronomical and nuclear sciences
- Origins and Evolution of Life
- Space Exploration and Technology
- Methane Hydrates and Related Phenomena
- Isotope Analysis in Ecology
- Geomagnetism and Paleomagnetism Studies
- Calibration and Measurement Techniques
- Geology and Paleoclimatology Research
- Spacecraft and Cryogenic Technologies
- Astronomical Observations and Instrumentation
- Cephalopods and Marine Biology
- Advanced Chemical Physics Studies
- Geological Studies and Exploration
Laboratoire d'Astrophysique de Bordeaux
2015-2024
Université de Bordeaux
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Institut d'Astrophysique de Paris
2018
Sorbonne Université
2018
Sapienza University of Rome
2018
Eclipse Research Consultants (United Kingdom)
2014-2017
European Space Research and Technology Centre
2016
Observatoire Aquitain des Sciences de l'Univers
2002-2014
Scottish and Southern Energy (United Kingdom)
2013
Past studies addressing the thermal atmospheric escape of hydrogen from "hot Jupiters" have been based on planet's effective temperature, which, as we show here, is not physically relevant for loss processes. In consequence, these led to significant underestimations rate (≤103 g s-1) and conclusion long-term stability. From more realistic exospheric temperatures, determined X-ray extreme-ultraviolet (XUV) irradiation conduction in thermosphere, find that energy-limited expansion arise,...
Context.Thanks to remarkable progress, radial velocity surveys are now able detect terrestrial planets at habitable distance from low-mass stars. Recently, two with minimum masses below 10 have been reported in a triple system around the M-type star Gliese 581. These found orbital distances comparable location of boundaries zone their star.
We present a novel chemical database for gas-phase astrochemistry. Named the KInetic Database Astrochemistry (KIDA), this consists of reactions with rate coefficients and uncertainties that will be vetted to greatest extent possible. Submissions measured calculated are welcome, studied by experts before inclusion into database. Besides providing kinetic information interstellar medium, KIDA is planned contain such data planetary atmospheres circumstellar envelopes. Each year, subset in...
Context.A study of the mass loss enhancement for very close "Hot Jupiters" due to gravitational field host star is presented.
Thousands of exoplanets have now been discovered with a huge range masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface their host star. However, essential nature these remains largely mysterious: there is no known, discernible pattern linking presence, size, or orbital parameters planet its parent We little idea whether chemistry linked formation environment, type star drives physics planet's birth, evolution. ARIEL was conceived observe number...
The quest for Earth-like planets represents a major focus of current exoplanet research. While that are Earth-sized and smaller have been detected, these reside in orbits too close to their host star allow liquid water on surface. We present the detection Kepler-186f, 1.11+\-0.14 Earth radius planet is outermost five - all roughly transit 0.47+\-0.05 Rsun star. intensity spectrum star's radiation places Kepler-186f stellar habitable zone, implying if has an atmosphere H2O at its surface,...
The inner edge of the classical habitable zone is often defined by critical flux needed to trigger runaway greenhouse instability. This 1D notion a flux, however, may not be so relevant for inhomogeneously irradiated planets, or when water content limited (land planets). Here, based on results from our 3D global climate model, we find that circulation pattern can shift super-rotation stellar/anti stellar equatorial Rossby deformation radius significantly exceeds planetary radius. Using...
Abstract We have collected transit times for the TRAPPIST-1 system with Spitzer Space Telescope over four years. add to these ground-based, HST, and K2 transit-time measurements, revisit an N -body dynamical analysis of seven-planet using our complete set from which we refine mass ratios planets star. next carry out a photodynamical light curves derive density host star planet densities. find that all seven planets’ densities may be described single rocky mass–radius relation is depleted in...
Ultracool dwarfs (UCD; Teff < ∼3000 K) cool to settle on the main sequence after ∼1 Gyr. For brown dwarfs, this cooling never stops. Their habitable zones (HZ) thus sweeps inward at least during first Gyr of their lives. Assuming they possess water, planets found in HZ UCDs have experienced a runaway greenhouse phase too hot for liquid water prior enter HZ. It has been proposed that such are desiccated by early and as dry worlds. Here, we model loss pre-HZ taking into account recent upper...
Radial velocity monitoring has found the signature of a $M \sin i = 1.3$~M$_\oplus$ planet located within Habitable Zone (HZ) Proxima Centauri \citep{Anglada16}. Despite hotter past and an active host star Proxima~b could have retained enough volatiles to sustain surface habitability \citep{Ribas2016}. Here we use 3D Global Climate Model (GCM) simulate b's atmosphere water cycle for its two likely rotation modes (1:1 3:2 spin-orbit resonances) while varying unconstrained inventory...
Proxima b is a planet with minimum mass of 1.3 MEarth orbiting within the habitable zone (HZ) Centauri, very low-mass, active star and Sun's closest neighbor. Here we investigate number factors related to potential habitability its ability maintain liquid water on surface. We set stage by estimating current high-energy irradiance show that currently receives 30 times more EUV radiation than Earth 250 X-rays. compute time evolution star's spectrum, which essential for modeling flux received...
Context. The TRAPPIST-1 system hosts seven Earth-sized, temperate exoplanets orbiting an ultra-cool dwarf star. As such, it represents a remarkable setting to study the formation and evolution of terrestrial planets that formed in same protoplanetary disk. While sizes are all known better than 5% precision, their densities have significant uncertainties (between 28% 95%) because poor constraints on planet's masses. Aims.The goal this paper is improve our knowledge planetary masses using...
Seven rocky planets orbit the nearby dwarf star TRAPPIST-1, providing a unique opportunity to search for atmospheres on small outside Solar System (Gillon et al., 2017). Thanks recent launch of JWST, possible atmospheric constituents such as carbon dioxide (CO2) are now detectable (Morley 2017, Lincowski 2018}. Recent JWST observations innermost planet TRAPPIST-1 b showed that it is most probably bare rock without any CO2 in its atmosphere (Greene 2023). Here we report detection thermal...
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....
Atmospheric erosion of CO2 -rich Earth-size exoplanets due to coronal mass ejection (CME)-induced ion pick up within close-in habitable zones active M-type dwarf stars is investigated. Since M are at the X-ray and extreme ultraviolet radiation (XUV) wave-lengths over long periods time, we have applied a thermal balance model various XUV flux input values for simulating thermospheric heating by photodissociation ionization processes exothermic chemical reactions cooling infrared in 15 μm...
Low mass M- and K-type stars are much more numerous in the solar neighborhood than solar-like G-type stars. Therefore, some of them may appear as interesting candidates for target star lists terrestrial exoplanet (i.e., planets with mass, radius, internal parameters identical to Earth) search programs like Darwin (ESA) or Terrestrial Planet Finder Coronagraph/Inferometer (NASA). The higher level stellar activity low M stars, compared G well closer orbital distances their habitable zones...
We study the interaction between planetary magnetosphere and atmosphere of close-in extrasolar planets HD 209458b OGLE-TR-56b with stellar wind during evolution their host stars. Recent astrophysical observations solar-like stars indicate that radiation particle environments young are orders magnitudes larger than for ages comparable to sun (~4.6 Gyr). model present early evolutionary stages, showing it is possible "Hot Jupiters" have an ionosphere-stellar like Venus. Our suggests internal...
We include the effect of evaporation in our evolutionary calculations close-in giant planets, based on a recent model for thermal taking into account XUV flux parent star (Lammer et al. [CITE]). Our analysis leads to existence critical mass given orbital distance below which timescale becomes shorter than planet. For planets with initial masses mcrit, rapid expansion outer layers and total planetary radius, speeding up process. Consequently, planet does not survive as long estimated by...
Darwin (ESA) and Terrestrial Planet Finder-TPF (NASA) are two projects of space telescopes aiming at the detection extra-solar terrestrial planets some their atmospheric components. In particular, they will be sensitive to 9.6 μm band which may signature an -rich atmosphere produced by photosynthetic life forms. this paper, we point out that , hence can also photochemistry investigate risk "false positive" incurred these missions. For purpose, have developed new photochemical...