E. Meier Valdés
A5088395092- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Calibration and Measurement Techniques
- Atmospheric Ozone and Climate
- Adaptive optics and wavefront sensing
- Spectroscopy and Laser Applications
- Pulsars and Gravitational Waves Research
- Geophysics and Gravity Measurements
- High-pressure geophysics and materials
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
University of Bern
2021-2024
The recent inference of sulfur dioxide (SO2) in the atmosphere hot (approximately 1,100 K), Saturn-mass exoplanet WASP-39b from near-infrared JWST observations1-3 suggests that photochemistry is a key process high-temperature atmospheres4. This because low (<1 ppb) abundance SO2 under thermochemical equilibrium compared with produced H2O and H2S (1-10 ppm)4-9. However, was made single, small molecular feature transmission spectrum at 4.05 μm and, therefore, detection other absorption bands...
M-dwarf systems offer an opportunity to study terrestrial exoplanetary atmospheres due their small size and cool temperatures. However, the extreme conditions imposed by these host stars raise a question about whether close-in rocky planets are able retain any atmosphere at all. The Hot Rocks Survey aims answer this targeting nine different spanning range of planetary stellar properties. Of these, LHS 1478 b orbits M3-type star, has equilibrium temperature T_ eq receives $21$ times Earth's...
Context. 55 Cnc e is an ultra-short period super-Earth transiting a Sun-like star. Previous observations in the optical range detected time-variable flux modulation that phased with planetary orbital period, whose amplitude too large to be explained by reflected light and thermal emission alone. Aims. The goal of study investigate origin variability timescale phase-curve e. To this end, we used CHaracterising ExOPlanet Satellite (CHEOPS), exquisite photometric precision provides opportunity...
The disintegrating ultra-short period rocky exoplanet K2-22b periodically emits dusty clouds in a dynamically chaotic process resulting variable transit depth from 0-1.3%. effluents that sublimate off the surface and condense out space are probably representative of formerly interior layers convectively transported to molten surface. Transmission spectroscopy these transiting reveal spectral fingerprints composition this world. We used JWST's Mid-Infrared Instrument (MIRI) as low-resolution...
Terrestrial exoplanets orbiting nearby small cool stars, known as M dwarfs, are well suited for an atmospheric characterisation. Because the intense X-ray and UV (XUV) irradiation from dwarf host stars is strong, thought to be unable retain primordial hydrogen- or helium-dominated atmospheres. However, it currently unknown whether heavier secondary atmospheres can survive. The aim of Hot Rocks Survey programme determine in presence hosts. In sample nine programme, we TOI-1468 b has a...
The nature of the close-in rocky planet 55 Cnc e is puzzling despite having been observed extensively. Its optical and infrared occultation depths show temporal variability, in addition to a phase curve variability optical. We wish explore possibility that originates from being 3:2 spin-orbit resonance, thus showing different sides during occultations. proposed were awarded Cycle 1 time at James Webb Space Telescope (JWST) test this hypothesis. JWST/NIRCam five occultations (secondary...
55 Cnc e is in a 0.73 day orbit transiting Sun-like star. It has been observed that the occultation depth of this Super-Earth, with mass 8$M_{\bigoplus}$ and radius 2$R_{\bigoplus}$, changes significantly over time at mid-infrared wavelengths. Observations Spitzer measured change its day-side brightness temperature 1200 K, possibly driven by volcanic activity, magnetic star-planet interaction, or presence circumstellar torus dust. Previous evidence for variability was infrared range. Here we...
Recent TESS-based studies have suggested that the dayside of KELT-1b, a strongly-irradiated brown dwarf, is significantly brighter in visible light than what would be expected based on Spitzer observations infrared. We observe eight eclipses KELT-1b with CHEOPS (CHaracterising ExOPlanet Satellite) to measure its brightness temperature bluest passband observed so far, and model photometry jointly existing optical NIR from TESS, LBT, CFHT, Spitzer. Our modelling leads self-consistent spectrum...
Past occultation and phase-curve observations of the ultra-short period super-Earth 55 Cnc e obtained at visible infrared wavelengths have been challenging to reconcile with a planetary reflection emission model. In this study, we analyse set 41 occultations over two-year timespan CHEOPS satellite. We report detection e's an average depth $12\pm3$ ppm. derive corresponding 2-$\sigma$ upper limit on geometric albedo $A_g < 0.55$ once decontaminated from thermal measured by Spitzer 4.5$\mu$m....
In the search for small exoplanets orbiting cool stars whose spectral energy distributions peak in near infrared, strong absorption of radiation this region due to water vapour atmosphere is a particularly adverse effect ground-based observations stars. To achieve photometric precision required detect it necessary mitigate impact variable precipitable (PWV) on radial-velocity and measurements. The aim enable global PWV correction by monitoring amount at zenith along line sight any visible...
Hot Jupiters are giant planets subject to intense stellar radiation. The physical and chemical properties of their atmosphere make them the most amenable targets for atmospheric characterization. In this paper we analyze photometry collected during secondary eclipses hot Jupiter by Our aim is characterize planet measuring eclipse depth in several passbands constrain planetary dayside spectrum. We updated radius ephemeris analyzing transit also analyzed CHEOPS, TESS, occultations planet, at...
Hot Jupiters are giant planets subject to intense stellar radiation. The physical and chemical properties of their atmosphere makes them the most amenable targets for atmospheric characterization. In this paper we analyze photometry collected during secondary eclipses hot Jupiter WASP-3 b by CHEOPS, TESS Spitzer. Our aim is characterize planet measuring eclipse depth in several passbands constrain planetary dayside spectrum. update consistent with previous works. analysis occultations...
55 Cnc e is an ultra-short period super-Earth transiting a Sun-like star. Previous observations in the optical range detected time-variable flux modulation that phased with planetary orbital period, whose amplitude too large to be explained by reflected light and thermal emission alone. The goal of study investigate origin variability timescale phase-curve e. To this end, we used CHaracterising ExOPlanet Satellite (CHEOPS), exquisite photometric precision provides opportunity characterise...
Recent TESS-based studies have suggested that the dayside of KELT-1b, a strongly-irradiated brown dwarf, is significantly brighter in visible light than what would be expected based on Spitzer observations infrared. We observe eight eclipses KELT-1b with CHEOPS (CHaracterising ExOPlanet Satellite) to measure its brightness temperature bluest passband observed so far, and model photometry jointly existing optical NIR from TESS, LBT, CFHT, Spitzer. Our modelling leads self-consistent spectrum...
Past occultation and phase-curve observations of the ultra-short period super-Earth 55 Cnc e obtained at visible infrared wavelengths have been challenging to reconcile with a planetary reflection emission model. In this study, we analyse set 41 occultations over two-year timespan CHEOPS satellite. We report detection e's an average depth $12\pm3$ ppm. derive corresponding 2-$σ$ upper limit on geometric albedo $A_g < 0.55$ once decontaminated from thermal measured by Spitzer 4.5$μ$m....