A5029206044- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
- Geophysics and Gravity Measurements
- Galaxies: Formation, Evolution, Phenomena
- Solar and Space Plasma Dynamics
- Atmospheric Ozone and Climate
- Calibration and Measurement Techniques
- Spectroscopy and Laser Applications
- Gamma-ray bursts and supernovae
- Scientific Research and Discoveries
- Astronomical and nuclear sciences
- Space Exploration and Technology
- CCD and CMOS Imaging Sensors
- Space Science and Extraterrestrial Life
- Historical Astronomy and Related Studies
- Molecular Spectroscopy and Structure
- Spacecraft and Cryogenic Technologies
- Space exploration and regulation
- Spectroscopy and Chemometric Analyses
- Spaceflight effects on biology
University of Geneva
2004-2018
University of Exeter
2008-2016
Institut National de Recherches Archéologiques Préventives
1992-2016
Optica
2012
Exeter Hospital
2010
Netherlands Institute for Radio Astronomy
2009
University of Bern
2008-2009
Phillips Exeter Academy
2009
Observatoire Cantonal de Neuchâtel
1998-2008
Global Social Observatory
1995-2008
We present and discuss new determinations of metallicity, rotation, age, kinematics, Galactic orbits for a complete, magnitude-limited, kinematically unbiased sample 16 682 nearby F G dwarf stars. Our ~63 000 new, accurate radial-velocity observations nearly 13 500 stars allow identification most the binary in and, together with published photometry, Hipparcos parallaxes, Tycho-2 proper motions, few earlier radial velocities, complete kinematic information 14 139 These high-quality velocity...
<i>Aims. <i/>We report the discovery of very shallow (), periodic dips in light curve an active G9V star observed by CoRoT satellite, which we interpret as caused a transiting companion. We describe 3-colour data and complementary ground-based observations that support planetary nature companion.<i>Methods. used colours information, good angular resolution photometric in- out- transit, adaptive optics imaging, near-infrared spectroscopy, preliminary results from radial velocity measurements,...
Since the discovery of short-period exoplanets a decade ago, photometric surveys have been recognized as feasible method to detect transiting hot Jupiters. Many transit are now under way, with instruments ranging from 10-cm cameras Hubble Space Telescope. However, results these much below expected capacity, estimated in dozens detections per year. One reasons is presence systematics (``red noise'') time series. In general, yield predictions assume uncorrelated noise (``white noise''). this...
The nearby transiting planet HD 189733b was observed during three transits with the Advanced Camera for Surveys of Hubble Space Telescope in spectroscopic mode. resulting time-series 675 spectra covers 550–1050 nm range, a resolution element ∼8 nm, at extremely high accuracy (signal-to-noise ratio up to 10 000 50-nm intervals each individual spectrum). Using these data, we disentangle effects limb darkening, measurement systematics and spots on surface host star, calculate wavelength...
Among the 160 known exoplanets, mainly detected in large radial-velocity surveys, only 8 have a characterization of their actual mass and radius thanks to two complementary methods detection: radial velocities photometric transit. We started March 2004 an exoplanet-search programme biased toward high-metallicity stars which are more frequently host extra-solar planets. This survey aims detect close-in giant planets, most likely transit star. For this programme, high-precision measured with...
We present Hubble Space Telescope optical and near-ultraviolet transmission spectra of the transiting hot-Jupiter HD189733b, taken with repaired Imaging Spectrograph (STIS) instrument. The resulting cover range 2900-5700 Ang reach per-exposure signal-to-noise levels greater than 11,000 within a 500 bandwidth. used time series obtained during two transit events to determine wavelength dependance planetary radius measure exoplanet's atmospheric spectrum for first over this range. Our...
The hot Jupiter HD189733b is the most extensively observed exoplanet. Its atmosphere has been detected and characterised in transmission eclipse spectroscopy, its phase curve measured at several wavelengths. This paper brings together results of our campaign to obtain complete spectrum this planet from UV IR with HST, using STIS, ACS WFC3. We provide a new tabulation across entire visible range. radius ratio each wavelength band was rederived ensure consistent treatment bulk transit...
We report on the discovery of WASP-12b, a new transiting extrasolar planet with $R_{\rm pl}=1.79 \pm 0.09 R_J$ and $M_{\rm pl}=1.41 0.1 M_J$. The host star properties were derived from Monte Carlo Markov Chain analysis transit photometry radial velocity data. Furthermore, by comparing stellar spectrum theoretical spectra evolution models, we determined that is super-solar metallicity ([M/H]$=0.3^{+0.05}_{-0.15}$), late-F (T$_{\rm eff}=6300^{+200}_{-100}$ K) which evolving off zero age main...
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Transmission spectroscopy, which consists of measuring the wavelength-dependent absorption starlight by a planet's atmosphere during transit, is powerful probe atmospheric composition. However, expected signal typically orders magnitude smaller than instrumental systematics and results are crucially dependent on treatment latter. In this paper, we propose new method to infer transit parameters in presence systematic noise using Gaussian processes, technique widely used machine learning...
We have detected low-amplitude radial-velocity variations in two stars, USNO-B1.0 1219-0005465 (GSC 02265-00107 = WASP-1) and 0964-0543604 00522-01199 WASP-2). Both stars were identified as being likely host of transiting exoplanets the 2004 SuperWASP wide-field transit survey. Using newly-commissioned spectrograph SOPHIE at Observatoire de Haute-Provence, we found that both objects exhibit reflex orbital with amplitudes characteristic planetary-mass companions in-phase photometric orbits....
The transit spectrum of the exoplanet HD 189733b has recently been obtained between 0.55 and 1.05 μm. Here we present an analysis this spectrum. We develop first-order equations to interpret absorption spectra. In case 189733b, show that observed slope as a function wavelength is characteristic extinction proportional inverse fourth power (). Assuming dominated by Rayleigh scattering, derive atmospheric temperature 1340 ± 150 K. If molecular hydrogen responsible for pressure at planetary...
We present Hubble Space Telescope optical and near-IR transmission spectra of the transiting hot-Jupiter WASP-31b. The spectrum covers 0.3-1.7 $\mu$m at a resolution $R\sim$70, which we combine with Spitzer photometry to cover full-optical IR. is dominated by cloud-deck flat apparent wavelengths $>0.52\mu$m. cloud deck high altitudes low pressures, as it majority expected Na line H$_2$O features. While I absorption not clearly identified, resulting does show very strong potassium feature...
Nine extrasolar planets with masses between 110 and 430M are known to transit their star. The knowledge of radii allows an estimate composition, but uncertainties on equations state, opacities possible missing energy sources imply that only inaccurate constraints can be derived when considering each planet separately. Aims: We seek better understand the composition transiting by them as ensemble, comparing obtained planetary properties parent stars. Methods: use evolution models stellar ages...
This Letter reports on the photometric detection of transits Neptune-mass planet orbiting nearby M-dwarf star GJ 436. It is by far closest, smallest, and least massive transiting detected so far. Its mass slightly larger than Neptune's at . The shape depth transit lightcurves show that it crossing host disc near its limb (impact parameter ) size comparable to Uranus Neptune, km = main constituant therefore very likely be water ice. If current structure models are correct, an outer layer H/He...
Abstract We report on a new survey of metallicities, ages, and Galactic orbits for complete, magnitude-limited, kinematically unbiased all-sky sample 16 682 nearby F- G-dwarfs. Our ∼ 63 000 new, accurate radial velocities nearly 13 500 the stars, combined with Hipparcos parallaxes Tycho-2 proper motions, complete kinematic data 14 139 stars allow us to identify most binary in sample. Isochrone ages have been determined whenever reliable results are possible, particular attention realistic...
We report on the discovery of a substellar companion or massive Jupiter orbiting G5V star HD 16760 using spectrograph <i>SOPHIE<i/> installed OHP 1.93-m telescope. Characteristics and performances are presented, as well exoplanet consortium program. With minimum mass 14.3 , an orbital period 465 days eccentricity 0.067, 16760b seems to be located just at end distribution giant planets, close planet/brown-dwarf transition. Its quite circular orbit supports formation in gaseous protoplanetary disk.
We report the discovery of WASP-3b, third transiting exoplanet to be discovered by WASP and SOPHIE collaboration. WASP-3b transits its host star USNO-B1.0 1256−0285133 every 1.846 834 ± 0.000 002 d. Our high-precision radial velocity measurements present a variation with amplitude characteristic planetary-mass companion in phase light curve. Adaptive optics imaging shows no evidence for nearby stellar companions, line-bisector analysis excludes faint, unresolved binarity activity as cause...
<i>Aims. <i/>Extra-solar planet search programs require high-precision velocity measurements. They need to determine how differentiate between radial-velocity variations due Doppler motion and the noise induced by stellar activity.<i>Methods. <i/>We monitored active K2V star HD 189 733 its transiting planetary companion, which has a 2.2-day orbital period. We used high-resolution spectograph <i>SOPHIE<i/> mounted on 1.93-m telescope at Observatoire de Haute-Provence obtain 55 spectra of over...
Context. The CoRoT mission, a pioneer in exoplanet searches from space, has completed its first 150 days of continuous observations ~12000 stars the galactic plane. An analysis raw data identifies most promising candidates and triggers ground-based follow-up. Aims. We report on discovery transiting planet CoRoT-Exo-2b, with period 1.743 days, characterize main parameters. Methods. filter light curve cosmic impacts, orbital residuals, low frequency signals star. folded 78 transits is fitted...
We monitored three transits of the giant gas planet around nearby K dwarf HD 189733 with ACS camera on Hubble Space Telescope. The resulting very-high accuracy lightcurve (signal-to-noise ratio near 15 000 individual measurements, 35 10-min averages) allows a direct geometric measurement orbital inclination, radius and scale system: i = 85.68 ± 0.04, 0.1572 0.0004, 8.92 0.09. derive improved values for stellar planetary radius, R* 0.755 0.011 , Rpl 1.154 0.017 RJ, transit ephemerides, Ttr...