A5089934053- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- Gamma-ray bursts and supernovae
- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- GNSS positioning and interference
- Geophysics and Gravity Measurements
- Calibration and Measurement Techniques
- Solar and Space Plasma Dynamics
- Astrophysical Phenomena and Observations
- Scientific Research and Discoveries
- Planetary Science and Exploration
- Pulsars and Gravitational Waves Research
- Isotope Analysis in Ecology
- Cosmology and Gravitation Theories
- Photorefractive and Nonlinear Optics
- Space Science and Extraterrestrial Life
- Optical Coatings and Gratings
Leiden University
2016-2025
University of California, Berkeley
2024
Leiden Observatory
2007-2023
Observatoire de Paris
2022
Université Grenoble Alpes
2022
Centre National de la Recherche Scientifique
2022
Université de Versailles Saint-Quentin-en-Yvelines
2022
Sorbonne Université
2022
Université Paris Cité
2022
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2022
Various theoretical models treating the effect of stellar irradiation on planetary envelopes predict presence a radius valley: i.e. bimodal distribution planet radii, with super-Earths and sub-Neptune planets separated by valley at around $\approx 2~R_\oplus$. Such was observed recently, owing to an improvement in precision stellar, therefore radii. Here we investigate presence, location shape such using small sample highly accurate parameters determined from asteroseismology, which includes...
We present the easy-to-use, publicly available, Python package petitRADTRANS, built for spectral characterization of exoplanet atmospheres. The code is fast, accurate, and versatile; it can calculate both transmission emission spectra within a few seconds at low resolution ($λ/Δλ$ = 1000; correlated-k method) high ($λ/Δλ= 10^6$; line-by-line method), using only lines input instruction. somewhat slower method used because more accurate than methods such as opacity sampling. Clouds be included...
Abstract We report a 4.8σ detection of water absorption features in the day side spectrum hot Jupiter HD 189733 b. used high-resolution (R ∼ 100 000) spectra taken at 3.2 μm with CRIRES on VLT to trace radial-velocity shift planet's atmosphere during 5 h its 2.2 d orbit as it approached secondary eclipse. Despite considerable telluric contamination this wavelength regime, we detect signal within our uncertainties expected combination systemic velocity ($V_{\rm sys}=-3^{+5}_{-6}$ km s−1) and...
Context. Ground-based high-dispersion (R ~ 100 000) spectroscopy (HDS) is proving to be a powerful technique with which characterize extrasolar planets. The planet signal distilled from the bright starlight, combining ral and time-differential filtering techniques. In parallel, high-contrast imaging (HCI) developing rapidly, aimed at spatially separating star. While HDS limited by overwhelming noise host star, HCI residual quasi-static speckles. Both techniques currently reach planet-star...
ABSTRACT Giant exoplanets orbiting very close to their parent star (hot Jupiters) are subject tidal forces expected synchronize rotational and orbital periods on short timescales (tidal locking). However, spin rotation has never been measured directly for hot Jupiters. Furthermore, atmospheres can show equatorial super-rotation via strong eastward jet streams, and/or high-altitude winds flowing from the day- night-side hemisphere. Planet atmospheric circulation broaden distort planet...
Exoplanet observations promise one day to unveil the presence of extraterrestrial life. Atmospheric compounds in strong chemical disequilibrium would point large-scale biological activity just as oxygen and methane do Earth's atmosphere. The cancellation both Terrestrial Planet Finder Darwin missions means that it is unlikely a dedicated space telescope search for biomarker gases exoplanet atmospheres will be launched within next 25 years. Here we show ground-based telescopes provide...
[Abridged] After many attempts over more than a decade, high-resolution spectroscopy has recently delivered its first detections of molecular absorption in exoplanet atmospheres, both transmission and thermal emission spectra. Targeting the combined signal from individual lines bands, these measurements use variations planet radial velocity to disentangle telluric stellar contaminants. In this paper we apply high resolution probe day-side spectrum bright transiting hot Jupiter HD 189733b. We...
Abstract We report the detection of water absorption features in day side spectrum first-known hot Jupiter, 51 Peg b, confirming star–planet system to be a double-lined spectroscopic binary. use high-resolution ( <?CDATA $R\approx $?> 100,000), $3.2\,\mu {\rm{m}}$?> spectra taken with CRIRES/VLT trace radial-velocity shift planet’s atmosphere during 4 hr its 4.23 orbit after superior conjunction. detect signature molecular by at significance $5.6\sigma systemic velocity...
Context. Clouds are ubiquitous in exoplanet atmospheres and they represent a challenge for the model interpretation of their spectra. When generating large number spectra, complex cloud models often prove too costly numerically, whereas more efficient may be overly simplified. Aims. We aim to constrain atmospheric properties directly imaged planet HR 8799e with free retrieval approach. Methods. used our radiative transfer code petitRADTRANS which we coupled PyMultiNest tool. added effect...
Context. The first detection of an atmosphere around extrasolar planet was presented by Charbonneau and collaborators in 2002. In the optical transmission spectrum transiting exoplanet HD 209458b, absorption signal from sodium measured at a level 0.023 ± 0.006%, using STIS spectrograph on Hubble Space Telescope. Despite several attempts, so far only upper limits to Na D have been obtained telescopes ground, HST result has yet be confirmed.
We present three transit observations of HD 189733 b obtained with the high-resolution spectrograph CARMENES at Calar Alto. A strong absorption signal is detected in near-infrared He I triplet 10830 Å all transits. During mid-transit, mean level $0.88\pm0.04$ % measured a $\pm$10 km s$^{-1}$ range net blueshift $-3.5\pm0.4$ (10829.84--10830.57 Å). The exhibits radial velocities $+6.5\pm3.1$ and $-12.6\pm1.0$ during ingress egress, respectively; planetary rest frame. show that stellar...
In this paper we present ground-based high-resolution spectroscopy of 51 Pegasi using CRIRES at the Very Large Telescope. The system was observed for 3x5 hours 2.3 {\mu}m a spectral resolution R = 100,000, targeting potential signatures from carbon monoxide, water vapour and methane in planet's dayside spectrum. first 2x5 data, find combined signal monoxide absorption formal 5.9{\sigma} confidence level, indicating non-inverted atmosphere. We derive planet mass M_P (0.46 +- 0.02) M_Jup an...
Context. GJ 1214b, the 6.55 Earth-mass transiting planet recently discovered by MEarth team, has a mean density of ~35% that Earth. It is thought this either mini-Neptune, consisting rocky core with thick, hydrogen-rich atmosphere, or composition dominated water.
(Abridged) In recent years, ground-based high-resolution spectroscopy has become a powerful tool for investigating exoplanet atmospheres. It allows the robust identification of molecular species, and it can be applied to both transiting non-transiting planets. Radial-velocity measurements star HD 179949 indicate presence giant planet companion in close-in orbit. Here we present analysis spectra system at 2.3 micron, obtained resolution R~100,000, during three nights observations with CRIRES...
Hot gas giant exoplanets can lose part of their atmosphere due to strong stellar irradiation, and these losses affect physical chemical evolution. Studies atmospheric escape from have mostly relied on space-based observations the hydrogen Lyman-α line in far ultraviolet region, which is strongly affected by interstellar absorption. Using ground-based high-resolution spectroscopy, we detected excess absorption helium triplet at 1083 nanometers during transit Saturn-mass exoplanet WASP-69b, a...
Context: Recently, the He I triplet at 10830 \r{A} has been rediscovered as an excellent probe of extended and possibly evaporating atmospheres close-in transiting planets. This already resulted in detections this a handful planets, both from space ground. However, while strong signal is expected for hot Jupiter HD 209458 b, only upper limits have obtained so far. Aims: Our goal to measure helium excess absorption b assess atmosphere planet possible evaporation. Methods: We new...
Broadband secondary-eclipse measurements of hot Jupiters have indicated the existence atmospheric thermal inversions, but their presence is difficult to determine from broadband because degeneracies between molecular abundances and temperature structure. We apply high-resolution (R = 100 000) infrared spectroscopy probe temperature-pressure profile HD 209458 b. This bright, transiting hot-Jupiter has long been considered gold standard for a Jupiter with an inversion layer, this challenged in...