A. Wünsche
A5031624934- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astronomical and nuclear sciences
- Adaptive optics and wavefront sensing
- Solar and Space Plasma Dynamics
- High-pressure geophysics and materials
- History and Developments in Astronomy
- Astrophysical Phenomena and Observations
- Regional Economic and Spatial Analysis
Université Grenoble Alpes
2015-2021
Centre National de la Recherche Scientifique
2015-2021
Institut de Planétologie et d'Astrophysique de Grenoble
2015-2018
Universidade do Porto
2016
Institute of Astrophysics and Space Sciences
2016
Context. Low mass stars are currently the best targets for searches rocky planets in habitable zone of their host star. Over last 13 years, precise radial velocities measured with HARPS spectrograph have identified over a dozen super-Earths and Earth-mass (msin i<10Mearth ) around M dwarfs, well understood selection function. This defined sample informs on frequency occurrence distribution orbital parameters, therefore already constrains our understanding planetary formation. The subset...
The combination of high-contrast imaging and high-dispersion spectroscopy, which has successfully been used to detect the atmosphere a giant planet, is one most promising potential probes Earth-size worlds. forthcoming generation extremely large telescopes (ELTs) may obtain sufficient contrast with this technique O$_2$ in those worlds that orbit low-mass M dwarfs. This strong motivation carry out census planets around cool stars for habitable zones can be resolved by ELTs, i.e. dwarfs within...
Abstract LHS 1140 is a nearby mid-M dwarf known to host temperate rocky super-Earth (LHS b) on 24.737-day orbit. Based photometric observations by MEarth and Spitzer as well Doppler spectroscopy from the High Accuracy Radial velocity Planet Searcher, we report discovery of an additional transiting companion c) with mass 1.81 ± 0.39 M ⊕ radius 1.282 0.024 R tighter, 3.77795-day We also obtain more precise estimates for b, which are 6.98 0.89 1.727 0.032 . The mean densities planets b c 7.5...
Abstract We present an estimate of the occurrence rate hot Jupiters (7 R ⊕ ≤ p 2 J , 0.8 P b 10 days) around early-type M dwarfs based on stars observed by Transiting Exoplanet Survey Satellite (TESS) during its primary mission. adopt stellar parameters from TESS Input Catalog and construct a sample 60,819 with 10.5 T mag 13.5, effective temperatures 2900 eff 4000 K, masses 0.45 * 0.65 ⊙ . conduct uninformed transit search using detection pipeline box least square characterize searching...
Abstract The ExoClock project is an inclusive, integrated, and interactive platform that was developed to monitor the ephemerides of Ariel targets increase mission efficiency. makes best use all available resources, i.e., observations from ground telescopes, midtime values literature, finally, space instruments. Currently, network includes 280 participants with telescopes capable observing 85% currently known candidate targets. This work results ∼1600 obtained up 2020 December 31 network....
The bright M dwarf K2-18 at 34 pc is known to host a transiting super-Earth-sized planet orbiting within the star's habitable zone; K2-18b. Given superlative nature of this system for studying an exoplanetary atmosphere receiving similar levels insolation as Earth, we aim characterize planet's mass which required interpret atmospheric properties and infer bulk composition. We obtain precision radial velocity measurements with HARPS spectrograph couple those K2 photometry jointly model...
GJ1132 is a nearby red dwarf known to host transiting Earth-size planet. After its initial detection, we pursued an intense follow-up with the HARPS velocimeter. We now confirm detection of GJ1132b radial velocities only. refined orbital parameters and, in particular, mass ($m_b = 1.66\pm0.23 M_\oplus$), density ($ρ_b 6.3\pm1.3$ g.cm$^{-3}$) and eccentricity ($e_b < 0.22 $; 95\%). also detect at least one more planet system. GJ1132c super-Earth period $P_c 8.93\pm0.01$ days minimum $m_c...
Abstract The ExoClock project has been created to increase the efficiency of Ariel mission. It will achieve this by continuously monitoring and updating ephemerides candidates, in order produce a consistent catalog reliable precise ephemerides. This work presents homogenous updated for 450 planets, generated integration ∼18,000 data points from multiple sources. These sources include observations ground-based telescopes (the network Exoplanet Transit Database), midtime values literature,...
We report the discovery of a super-Earth orbiting star GJ 536 based on analysis radial-velocity time series from HARPS and HARPS-N spectrographs. b is planet with minimum mass Msini 5.36 ± 0.69 M⊕; it has an orbital period 8.7076 0.0025 d at distance 0.066610(13) AU, orbit that consistent circular. The host moderately quiet M1 V 536, located 10 pc Sun. find presence second signal 43 we relate to stellar rotation after analysing Ca II H&K Hα spectroscopic indicators photometric data ASAS...
Exoplanet surveys have shown that systems with multiple low-mass planets on compact orbits are common. Except for few cases, however, the masses of these generally unknown. At very end main sequence, host stars lowest mass and hence offer largest reflect motion a given planet. In context, we monitored (0.13Msun) M dwarf YZ Cet (GJ 54.1, HIP 5643) intensively obtained both radial velocities stellar-activity indicators derived from spectroscopy photometry. We find strong evidence it is orbited...
The Ariel mission will observe spectroscopically around 1000 exoplanets to further characterise their atmospheres. For the be as efficient possible, a good knowledge of planets' ephemerides is needed before its launch in 2028. While for some planets are being refined on per-case basis, an organised effort collectively verify or update them when necessary does not exist. In this study, we introduce ExoClock project, open, integrated and interactive platform with purpose producing confirmed...
We homogeneously analyse $\sim 3.2\times 10^5$ photometric measurements for 1100$ transit lightcurves belonging to $17$ exoplanet hosts. The data cover $16$ years 2004--2019 and include amateur professional observations. Old archival were reprocessed using up-to-date exoplanetary parameters empirically debiased limb-darkening models. also derive self-consistent radial-velocity fits $13$ targets. confirm the nonlinear TTV trend in WASP-12 at a high significance, with consistent magnitude....
We present the confirmation of a new sub-Neptune close to transition between super-Earths and sub-Neptunes transiting M2 dwarf TOI- 269 (TIC 220479565, V = 14.4 mag, J 10.9 Rstar 0.40 Rsun, Mstar 0.39 Msun, d 57 pc). The exoplanet candidate has been identified in multiple TESS sectors, validated with high-precision spectroscopy from HARPS ground-based photometric follow-up ExTrA LCO-CTIO. determined mass, radius, bulk density by jointly modeling both photometry radial velocities juliet. an...
ABSTRACT Short-period gas giant planets have been shown to be significantly rarer for host stars less massive than the Sun. We report discovery of two transiting – TOI-2379 b and TOI-2384 with low-mass (early M) stars. Both were detected using Transiting Exoplanet Survey Satellite photometry both transit signal was validated ground-based photometric facilities. confirm planetary nature these companions measure their masses radial velocity observations. find that has an orbital period 5.469 d...
K2 space observations recently found that three super-Earths transit the nearby M dwarf K2-3. The apparent brightness and small physical radius of their host star rank these planets amongst most favourable for follow-up characterisations. outer planet orbits close to inner edge habitable zone might become one first exoplanets searched biomarkers using transmission spectroscopy. We used HARPS velocimeter measure mass planets. b is 8.4 ± 2.1 M⊕, while our determination those c d are affected...
In an earlier campaign to characterize the mass of transiting temperate super-Earth K2-18b with HARPS, a second, non-transiting planet was posited exist in system at ~9 days. Further radial velocity follow-up CARMENES spectrograph visible channel revealed much weaker signal 9 days, which also appeared vary chromatically and temporally, leading conclusion that origin 9-day more likely related stellar activity than planetary presence. Here we conduct detailed reanalysis all available RV...
We report follow-up observations of transiting exoplanets that have either large uncertainties (>10 minutes) in their transit times or not been observed for over three years. A fully robotic ground-based telescope network, from citizen astronomers and data TESS used to study eight planets, refining ephemeris orbital data. Such are key ensuring accurate upcoming ground space-based telescopes which may seek characterise the atmospheres these planets. find deviations expected time all with...
M-dwarf stars are promising targets for identifying and characterizing potentially habitable planets. K2-3 is a nearby (45 pc), early-type M dwarf hosting three small transiting planets, the outermost of which orbits close to inner edge stellar (optimistic) zone. The system well suited follow-up characterization studies aimed at determining accurate masses bulk densities Using total 329 radial velocity measurements collected over 2.5 years with HARPS-N HARPS spectrographs proper treatment...
We announce the discovery of GPX-1 b, a transiting brown dwarf with mass $19.7\pm 1.6$ $M_{\mathrm{Jup}}$ and radius $1.47\pm0.10$ $R_{\mathrm{Jup}}$, first sub-stellar object discovered by Galactic Plane eXoplanet (GPX) survey. The transits moderately bright ($V$ = 12.3 mag) fast-rotating F-type star projected rotational velocity $v\sin{ i_*}=40\pm10$ km/s. use isochrone placement algorithm to characterize host star, which has effective temperature $7000\pm200$ K, $1.68\pm0.10$...