A5029203723- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Astronomical Observations and Instrumentation
- Space Exploration and Technology
- Atmospheric and Environmental Gas Dynamics
- Gamma-ray bursts and supernovae
- Iron Metabolism and Disorders
- Advanced Battery Technologies Research
- Erythropoietin and Anemia Treatment
- Fuel Cells and Related Materials
- Electric and Hybrid Vehicle Technologies
- Ionosphere and magnetosphere dynamics
- Isotope Analysis in Ecology
- Planetary Science and Exploration
- Mechanical Circulatory Support Devices
- Cardiac Arrest and Resuscitation
- Calibration and Measurement Techniques
- Astrophysical Phenomena and Observations
- Silicone and Siloxane Chemistry
University of Warwick
2019-2025
Leiden University
2022-2025
McLaren Northern Michigan
2025
MIT Art, Design and Technology University
2023
MIT World Peace University
2023
University of Cambridge
2017-2020
The University of Texas MD Anderson Cancer Center
2019
Loma Linda University
2004-2006
Loma Linda University Medical Center
2004-2006
Transmission spectroscopy of exoplanets has the potential to provide precise measurements atmospheric chemical abundances, in particular hot Jupiters whose large sizes and high temperatures make them conducive such observations. To date, several transmission spectra have revealed low amplitude features water vapour compared expectations from cloud-free atmospheres solar metallicity. The spectral amplitudes could either be due presence aerosols that obscure part atmosphere or inherently...
We present high-resolution dayside thermal emission observations of the exoplanet WASP-18b using IGRINS on Gemini South. remove stellar and telluric signatures standard algorithms, we extract planet signal via cross correlation with model spectra. detect atmosphere at a signal-to-noise ratio (SNR) 5.9 full chemistry model, measure H2O (SNR=3.3), CO (SNR=4.0), OH (SNR=4.8) individually, confirm previous claims inversion layer. The three species are confidently detected (>4$\sigma$) Bayesian...
We are entering the era of high-precision and high-resolution spectroscopy exoplanets. Such observations herald need for robust self-consistent spectral models exoplanetary atmospheres to investigate intricate atmospheric processes make observable predictions. Spectral plane-parallel exist, mostly adapted from other astrophysical applications, with different levels sophistication accuracy. There is a growing new generation custom-built exoplanets incorporating state-of-the-art numerical...
Abstract We find evidence for a strong thermal inversion in the dayside atmosphere of highly irradiated hot Jupiter WASP-18b ( , ) based on emission spectroscopy from Hubble Space Telescope secondary eclipse observations and Spitzer photometry. demonstrate lack water vapor either absorption or at 1.4 μ m. However, we infer 4.5 m 1.6 that attribute to CO, as well non-detection all other relevant species (e.g., TiO, VO). The most probable atmospheric retrieval solution indicates C/O ratio 1...
Thermal emission spectra of exoplanets provide constraints on the chemical compositions, pressure–temperature (P-T) profiles, and energy transport in exoplanetary atmospheres. Accurate inferences these properties rely robustness atmospheric retrieval methods employed. While extant codes have provided significant molecular abundances temperature profiles several atmospheres, their deviations from thermal equilibria yet to be fully explored. Our present work is a step this direction. We report...
The class of ultra-hot Jupiters comprises giant exoplanets undergoing intense irradiation from their host stars. They have proved to be a particularly interesting population for orbital and atmospheric properties. One such planet, WASP-121~b, is in highly misaligned orbit close its Roche limit, atmosphere exhibits thermal inversion. These properties make WASP-121~b an target additional characterization. In this paper, we present analysis archival high-resolution optical spectra obtained...
Abstract Ground-based high-resolution spectroscopy (HRS) has detected numerous chemical species and atmospheric dynamics in exoplanets, most notably ultrahot Jupiters (UHJs). However, quantitative estimates on abundances have been challenging but are essential for accurate comparative characterization to determine formation scenarios. In this work, we retrieve the atmospheres of six UHJs (WASP-76 b, MASCARA-4 MASCARA-2 WASP-121 HAT-P-70 WASP-189 b) with ESPRESSO HARPS-N/HARPS observations,...
Abstract We have entered the era of James Webb Space Telescope (JWST). use first JWST transmission spectrum hot Saturn-mass exoplanet, WASP-39 b, obtained with NIRSpec instrument in 3–5 μ m range to investigate (a) what atmospheric constraints are possible JWST-quality data this spectral range, (b) requirements for models used retrievals, (c) effect differences between reduction pipelines on retrieved properties, and (d) complementarity Hubble (HST) observations at shorter wavelengths....
Context . High-resolution spectrographs fed by adaptive optics (AO) provide a unique opportunity to characterize directly imaged exoplanets. Observations with such instruments allow us probe the atmospheric composition, spin rotation, and radial velocity of planet, thereby helping reveal information on its formation migration history. The recent upgrade Cryogenic High-Resolution Infrared Echelle Spectrograph (CRIRES+) at VLT makes it highly suitable instrument for characterizing Aims In this...
Exoplanets with relatively clear atmospheres are prime targets for detailed studies of chemical compositions and abundances in their atmospheres. Alkali metals have long been suggested to exhibit broad wings due pressure broadening, but most the alkali detections only show very narrow absorption cores, probably because presence clouds. We report strong detection pressure-broadened spectral profiles Na, K, Li atmosphere super-Neptune WASP-127b, at 4.1 σ , 5.0 3.4 respectively. performed a...
High-resolution doppler spectroscopy provides a powerful means for chemical detections in exoplanetary atmospheres. This approach involves monitoring hundreds of molecular lines the planetary spectrum shifted by orbital motion planet. The molecules are detected cross-correlating observed system with model spectrum. method has led to H2O, CO, and TiO hot Jupiters using large ground-based telescopes. Critical this method, however, is accurate removal stellar telluric features from spectrum,...
Molecular species in planetary atmospheres provide key insights into their atmospheric processes and formation conditions. In recent years, high-resolution Doppler spectroscopy the near-infrared has allowed detections of H$_2$O CO several hot Jupiters. This method involves monitoring spectral lines thermal emission Doppler-shifted due to radial velocity planet over its orbit. However, aside from H$_2$O, which are primary oxygen- carbon-bearing H$_2$-rich atmospheres, little else is known...
Thermal emission spectra of hot Jupiters have led to key constraints on thermal inversions (or 'stratospheres') in their atmospheres with important implications for atmospheric processes. Canonically, been suggested be caused by species such as TiO and VO which strong visible opacity absorb incident starlight. We explore two new avenues Jupiters, exploring both the infrared opacities atmospheres. Firstly, a range metal-rich we find that four (AlO, CaO, NaH MgH) provide comparable TiO/VO can...
Abstract Ultra-hot Jupiters (UHJs), giant exoplanets with equilibrium temperatures above 2000 K, are ideal laboratories for studying metal compositions of planetary atmospheres. At these the thermal dissociation metal-rich molecules into their constituent elements makes atmospheres conducive elemental characterization. Several elements, mostly ionized metals, have been detected in UHJs recently using high-resolution transit spectroscopy. Even though a number neutral transition metals (e.g.,...
ABSTRACT High-resolution spectroscopy (HRS) has been used to detect a number of species in the atmospheres hot Jupiters. Key such detections is accurately and precisely modelled spectra for cross-correlation against R ≳ 20 000 observations. There need latest generation opacities which form basis high signal-to-noise using spectra. In this study we present make publicly available cross-sections six molecular species, H2O, CO, HCN, CH4, NH3, CO2 line lists most suitable low- high-resolution...
ABSTRACT Exoplanet atmospheres are inherently three-dimensional systems in which thermal/chemical variation and winds can strongly influence spectra. Recently, the ultra-hot Jupiter WASP-76 b has shown evidence for condensation asymmetric Fe absorption with time. However, it is currently unclear whether these asymmetries driven by chemical or thermal differences between two limbs, as precise constraints on have remained elusive due to challenges of modelling dynamics a Bayesian framework. To...
The field of exo-atmospheric characterisation is progressing at an extraordinary pace. Atmospheric observations are now available for tens exoplanets, mainly hot and warm inflated gas giants, new molecular species continue to be detected revealing a richer atmospheric composition than previously expected. Thanks its equilibrium temperature (963$\pm$18~K) low-density (0.219$\pm$0.031~g cm$^{-3}$), the close-in giant WASP-69b represents golden target characterization. With aim searching...
Abstract Isotope ratios have recently been measured in the atmospheres of directly imaged and transiting exoplanets from ground-based observations. The arrival JWST allows us to characterize exoplanetary further detail opens up wavelengths inaccessible ground. In this work we constrain carbon oxygen isotopes 13 C, 18 O, 17 O CO atmosphere companion VHS 1256 b through retrievals ∼4.1–5.3 μ m NIRSpec G395H/F290LP observations early-release science program (ERS 1386). We detect C 16 12 at 32 σ...
Abstract Ultra-hot Jupiters (UHJs) are among the best targets for atmospheric characterization at high spectral resolution. Resolving their transmission spectra as a function of orbital phase offers unique window into 3D nature these objects. In this work, we present three transits UHJ WASP-121b observed with Gemini-S/IGRINS. For first time, measure phase-dependent absorption signals CO and H 2 O in atmosphere an exoplanet, find that they different. While blueshift increases during transit,...
Direct atmospheric retrievals of exoplanets at high-resolution have recently allowed for a more detailed characterisation their chemistry and dynamics from the ground. By monitoring longitudinal distribution species, as well varying vertical temperature structure between limbs WASP-76b, across multiple transits, we aim to enhance our understanding 3D nature chemical/dynamical evolution such objects over timescales months/years. We present three VLT/ESPRESSO observations ultra-hot Jupiter...
In the last decade ground based high resolution Doppler spectroscopy (HRS) has detected numerous species in transiting and non-transiting hot Jupiters, is ideally placed for atmospheric characterisation of warm Neptunes super Earths. Many these cooler smaller exoplanets have shown cloudy atmospheres from low near infrared observations, making constraints on chemical difficult. We investigate how HRS can improve given its sensitivity to spectral line cores which probe higher altitudes above...