M. Marmier
A5038782222- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Adaptive optics and wavefront sensing
- Geophysics and Gravity Measurements
- Space Exploration and Technology
- Galaxies: Formation, Evolution, Phenomena
- Calibration and Measurement Techniques
- Scientific Research and Discoveries
- Cryospheric studies and observations
- Molecular Spectroscopy and Structure
- Geomagnetism and Paleomagnetism Studies
University of Geneva
2015-2024
Global Social Observatory
2010-2020
Observatoire Cantonal de Neuchâtel
2008-2017
We report on the results of an 8-year survey carried out at La Silla Observatory with HARPS spectrograph to detect and characterize planets in super-Earth Neptune mass regime. The size our star sample precision achieved have allowed detection a sufficiently large number low-mass study statistical properties their orbital elements, correlation host-star metallicity planet masses, as well occurrence rate planetary systems around solar-type stars. A robust estimate frequency shows that more...
The discovery of 9 new brown-dwarf candidates orbiting stars in the CORALIE and HARPS radial-velocity surveys is reported. New radial velocities yielding accurate orbits 6 previously-known hosts potential companions are presented. Including targets selected from literature, 33 examined. Employing innovative methods, we use reduction Hipparcos data to fully characterise astrometric objects, revealing M-dwarf with masses between 90 M_Jup 0.52 M_Sun. Additionally, two can be restricted stellar...
We report the discovery of WASP-4b, a large transiting gas-giant planet with an orbital period 1.34 days. This is first to be discovered by SuperWASP-South observatory and CORALIE collaboration orbiting star brighter than 16th magnitude in southern hemisphere. A simultaneous fit high-quality light curves precision radial velocity measurements leads planetary mass 1.22+ 0.09−0.08 MJup radius 1.42+ 0.07−0.04 RJup. The host USNO-B1.0 0479–0948995, G7 V visual 12.5. As result short period,...
Data from the newly-commissioned \textit{Transiting Exoplanet Survey Satellite} (TESS) has revealed a "hot Earth" around LHS 3844, an M dwarf located 15 pc away. The planet radius of $1.32\pm 0.02$ $R_\oplus$ and orbits star every 11 hours. Although existence atmosphere such strongly irradiated is questionable, bright enough ($I=11.9$, $K=9.1$) for this possibility to be investigated with transit occultation spectroscopy. star's brightness planet's short period will also facilitate...
Abstract We report the detection of a transiting planet around π Men (HD 39091), using data from Transiting Exoplanet Survey Satellite ( TESS ). The solar-type host star is unusually bright V = 5.7) and was already known to Jovian on highly eccentric, 5.7 yr orbit. newly discovered has size 2.04 ± 0.05 R ⊕ an orbital period 6.27 days. Radial-velocity High-Accuracy Planet Searcher Anglo-Australian Telescope/University College London Echelle Spectrograph archives also displays day periodicity,...
Aims. We study a subset of the planetary population characterized both by HARPS and Kepler surveys. compare statistical properties planets in systems with m.sin i >5-10 M_Earth R>2 R_Earth. If we assume that underlying has same characteristics, different detection sensitivity to orbital inclination relative line sight allows us probe planets' mutual inclination. Methods. considered frequency one, two three as dictated data. used Kepler's period host mass radii distributions (corrected from...
We present the analysis of entire HARPS observations three stars that host planetary systems: HD1461, HD40307, and HD204313. The data set spans eight years contains more than 200 nightly averaged velocity measurements for each star. This means it is sensitive to both long-period low-mass planets also effects induced by stellar activity cycles. modelled using Keplerian functions correspond candidates included short- long-term magnetic activity. A Bayesian approach was taken modelling, which...
We present the discovery and characterisation of two transiting planets observed by \textit{TESS} in light curves young bright (V=9.67) star HD73583 (TOI-560). perform an intensive spectroscopic photometric space- ground-based follow-up order to confirm characterise system. found that is a ($\sim 500$~Myr) active with rotational period $12.08 \pm 0.11 $\,d, mass radius $ 0.73 0.02 M_\odot$ $0.65 R_\odot$, respectively. b ($P_b=6.3980420 _{ - 0.0000062 }^{+0.0000067}$ d) has $10.2...
Young, nearby stars are ideal targets to search for planets using the direct imaging technique. The determination of stellar parameters is crucial interpretation survey results particularly since luminosity substellar objects has a strong dependence on system age. We have conducted large program with NaCo at VLT in order and brown dwarfs wide orbits around 86 stars. A fraction observed were poorly investigated literature. performed study characterize fundamental properties (age, distance,...
We present 2271 radial velocity measurements taken on 118 single-line binary stars, over eight years with the CORALIE spectrograph. The binaries consist of F/G/K primaries and M dwarf secondaries. They were initially discovered photometrically by WASP planet survey, as their shallow eclipses mimic a hot Jupiter transit. observations we permit precise characterisation orbital elements mass function. With modelling primary star, this function is converted to secondary star. In future,...
Using high-contrast imaging with the SPHERE instrument at VLT, we report first images of a cold brown dwarf companion to exoplanet host star HD4113A. The HD4113C is part complex dynamical system consisting giant planet, stellar and known wide M-dwarf companion. Its separation $535\pm3$mas H-band contrast $13.35\pm0.10$mag correspond projected 22AU an isochronal mass estimate $36\pm5$M$_J$ based on COND models. shows strong methane absorption, through atmospheric model fitting surface gravity...
We report the detection of two very eccentric planets orbiting HD 4113 and 156846 with CORALIE Echelle spectrograph mounted on 1.2-m Euler Swiss telescope at La Silla. The first planet, b, has minimum mass ± , a period 0.21 days an eccentricity 0.02. It orbits metal rich G5V star AU, which displays additional radial velocity drift 28 m s-1 yr-1 observed during 8 years. combination radial-velocity data non-detection any main sequence stellar companion in our high contrast images, taken VLT...
Context. The young active star BD +20 1790 is believed to host a substellar companion, revealed by radial-velocity measurements that detected the reflex motion induced on parent star. Aims. A complete characterisation of signal necessary in order assess its nature. Methods. We used CORALIE spectrograph obtain precise (~10 m/s) velocity this star, while characterizing bisector span variations. Particular attention was given correctly sample both proposed planetary orbital period, 7.8 days,...
Context. Since 1998, a planet-search program around main sequence stars within 50 pc in the southern hemisphere has been carried out with CORALIE echelle spectrograph at La Silla Observatory.
We report the discovery of 1.008-day, ultra-short period (USP) super-Earth HD 213885b (TOI-141b) orbiting bright ($V=7.9$) star 213885 (TOI-141, TIC 403224672), detected using photometry from recently launched TESS mission. Using FEROS, HARPS and CORALIE radial-velocities, we measure a precise mass $8.8\pm0.6$ $M_\oplus$ for this $1.74 \pm 0.05$ $R_\oplus$ exoplanet, which provides enough information to constrain its bulk composition, is similar Earth's but enriched in iron. The radius,...
We report the Transiting Exoplanet Survey Satellite ($TESS$) detection of a multi-planet system orbiting $V=10.9$ K0 dwarf TOI 125. find evidence for up to five planets, with varying confidence. Three high signal-to-noise transit signals correspond sub-Neptune-sized planets ($2.76$, $2.79$, and $2.94\ R_{\oplus}$), we statistically validate planetary nature two inner ($P_b = 4.65$ days, $P_c 9.15$ days). With only transits observed, outer object ($P_{.03} 19.98$ days) as ratio planet...
We report the discovery of exoplanet K2-110 b (previously EPIC212521166b) from K2 photometry orbiting in a 13.8637d period around an old, metal-poor K3 dwarf star. With V-band magnitude 11.9, is particularly amenable to RV follow-up. A joint analysis and high-precision RVs 28 HARPS HARPS-N spectra reveal it have radius 2.6$\pm 0.1 R_{\oplus}$ mass 16.7$\pm 3.2$~M$_{\oplus}$, hence density $5.2\pm1.2$ g.cm$^{-3}$, making one most massive planets yet be found with sub-Neptune radius. When...
We introduce the BEBOP radial velocity survey for circumbinary planets. initiated this using CORALIE spectrograph on Swiss Euler Telescope at La Silla, Chile. An intensive four year observing campaign commenced in 2013, targeting 47 single-lined eclipsing binaries drawn from EBLM low mass binaries. Our specific use of with faint M dwarf companions avoids spectral contamination, providing conditions akin to single stars. By combining new observations existing ones programme, we report results...
This first VELOCE data release comprises 18,225 high-precision RV measurements of 258 bona fide classical Cepheids on both hemispheres collected mainly between 2010 and 2022, alongside 1161 additional observations 164 other stars. The median per-observation uncertainty is 0.037 km/s, some reach 0.002 km/s. Non-variable standard stars characterize zero-point stability provide a base for future cross-calibrations. We determined differences 31 literature sets using template fitting measured...
We report the detection of a double planetary system around HD 140718 as well discovery two long period and massive planets orbiting 171238 204313. Those discoveries were made with CORALIE Echelle spectrograph mounted on 1.2-m Euler Swiss telescope located at La Silla Observatory, Chile. The nearby G9 dwarf 147018 is composed an eccentric inner planet (e=0.47) twice mass Jupiter (2.1 MJup ) orbital 44.24 days. outer even more (6.6 MJup) slightly orbit (e=0.13) 1008 has minimum 2.6 MJup, 1523...
We report the period, eccentricity, and mass determination for TESS single-transit event candidate TOI-222, which displayed a single 3000 ppm transit in two-minute cadence data from Sector 2. determine orbital period via radial velocity measurements (P=33.9,days), allowed ground-based photometric detection of two subsequent transits. Our show that companion to TOI-222 is low star, with radius $0.18_{-0.10}^{+0.39}$ Rsun $0.23\pm0.01$ Msun. This discovery showcases ability efficiently...