A5065657640- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Spectroscopy and Laser Applications
- Isotope Analysis in Ecology
- Astronomical Observations and Instrumentation
- Nuclear Physics and Applications
- Planetary Science and Exploration
- Geomagnetism and Paleomagnetism Studies
- Adaptive optics and wavefront sensing
- Conservation Techniques and Studies
- Wind and Air Flow Studies
- Health and Well-being Studies
- Sensor Technology and Measurement Systems
- Water Quality Monitoring and Analysis
- Fluid Dynamics and Turbulent Flows
- Fluid Dynamics and Vibration Analysis
- Cephalopods and Marine Biology
- Optical and Acousto-Optic Technologies
- Dental materials and restorations
- Pigment Synthesis and Properties
University of Oxford
2020-2024
Queen's University Belfast
2024
Austrian Academy of Sciences
2018-2021
Space Research Institute
2018-2021
Saint Mary's University
2014-2018
Abstract We explore atmospheric escape from close-in exoplanets with the highest mass-loss rates. First, we locate transition stellar X-ray and UV-driven to rapid Roche lobe overflow, which occurs once 10–100 nbar pressure level in atmosphere reaches lobe. Planets enter this regime when ratio of substellar radius polar along visible surface level, aligns a constant potential, is X/Z ≳ 1.2 for Jovian planets ( M p 100 ⊕ ) 1.02 sub-Jovian ≈ ). Around Sun-like star, applies orbital periods less...
With a day-side temperature in excess of 4500K, comparable to mid-K-type star, KELT-9b is the hottest planet known. Its extreme makes particularly interesting test bed for investigating nature and diversity gas giant planets. We observed transit at high spectral resolution (R$\sim$94,600) with CARMENES instrument on Calar Alto 3.5-m telescope. Using these data, we detect first time ionized calcium (CaII triplet) absorption atmosphere KELT-9b; this second that CaII has been hot Jupiter. Our...
The inflated transiting hot Jupiter HD 209458b is one of the best studied objects since beginning exoplanet characterization. Transmission observations this system between mid infrared and far ultraviolet have revealed signature atomic, molecular, possibly aerosol species in lower atmosphere planet, as well escaping hydrogen metals upper atmosphere. From a re-analysis near-ultraviolet (NUV) transmission 209458b, we detect ionized iron (Fe II) absorption 100 A-wide range around 2370 A, lying...
ABSTRACT Ultrahot Jupiters (UHJs) undergo intense irradiation by their host stars and are expected to experience non-local thermodynamic equilibrium (NLTE) effects in atmospheres. Such computationally intensive model but, at the low pressures probed high-resolution cross-correlation spectroscopy (HRCCS), can significantly impact formation of spectral lines. The UHJ WASP-121 b exhibits a highly inflated atmosphere, making it ideal for investigating NLTE on its transmission spectrum. Here, we...
ABSTRACT High-resolution cross-correlation spectroscopy (HRCCS) combined with adaptive optics has been enormously successful in advancing our knowledge of exoplanet atmospheres, from chemistry to rotation and atmospheric dynamics. This powerful technique now drives major science cases for ELT instrumentation including METIS/ELT, GMTNIRS/GMT, MICHI/TMT, targeting biosignatures on rocky planets at 3–5 μm, but remains untested beyond 3.5 μm where the sky thermal background begins provide...
Abstract Extremely irradiated, close-in planets to early-type stars might be prone strong atmospheric escape. We review the literature showing that X-ray-to-optical measurements indicate for intermediate-mass (IMSs) cooler than ≈8250 K, X-ray and extreme-ultraviolet (XUV) fluxes are on average significantly higher those of solar-like stars, while hotter IMSs, because lack surface convection, it is opposite. construct spectral energy distributions prototypical comparing them solar. The XUV...
Context. The extreme contrast ratios between stars and their planets at optical wavelengths make it challenging to isolate the light reflected by exoplanet atmospheres. Yet, these reflective properties reveal key processes occurring in atmospheres, they also span that include potential O 2 biosignature. High resolution cross-correlation spectroscopy (HRCCS) offers a robust avenue for developing techniques extract reflection spectra. Aims. We aimed spectrum of non-transiting hot Jupiter 51...
Abstract We present the first transmission spectroscopy study of an exoplanet atmosphere with high-resolution mode new Gemini High-resolution Optical SpecTrograph (GHOST) instrument at South Observatory. observed one transit HAT-P-70 b—an ultra-hot Jupiter inflated radius—and made a detection infrared Ca ii triplet in its spectrum. The depth strongest line implies that substantial amount extends to least 47% above bulk planetary radius. lines are blueshifted between ∼3 5 km s −1 , indicative...
Context. Observationally constraining the atmospheric temperature-pressure (TP) profile of exoplanets is an important step forward for improving planetary atmosphere models, further enabling one to place detection spectral features and measurement atomic molecular abundances through transmission emission spectroscopy on solid ground. Aims. The aim constrain TP ultra-hot Jupiter KELT-9b by fitting synthetic spectra observed H$\alpha$ H$\beta$ lines identify why self-consistent models are...
Aims. We aim to extract the transmission spectrum of H I Balmer lines ultra-hot Jupiter (UHJ) KELT-20b/MASCARA-2b from observations and further compare results with what was obtained through forward modelling, accounting for non-local thermodynamic equilibrium (NLTE) effects. Methods. extracted line profiles six transits HARPS-N high-resolution spectrograph attached Telescopio Nazionale Galileo telescope. computed temperature-pressure (TP) profile employing HELIOS code in lower atmosphere C...
Context - Exoplanetary upper atmospheres are low density environments where radiative processes can compete with collisional ones and introduce non-local thermodynamic equilibrium (NLTE) effects into transmission spectra. Aims We develop a NLTE transfer framework capable of modelling exoplanetary spectra over wide range planetary properties. Methods adapt the spectral synthesis code Cloudy to produce an atmospheric structure atomic spectrum in both local (LTE) for hot Jupiter HD209458b,...
High-resolution cross-correlation spectroscopy (HRCCS) combined with adaptive optics has been enormously successful in advancing our knowledge of exoplanet atmospheres, from chemistry to rotation and atmospheric dynamics. This powerful technique now drives major science cases for ELT instrumentation including METIS/ELT, GMTNIRS/GMT MICHI/TMT, targeting biosignatures on rocky planets at 3-5 $\mu$m, but remains untested beyond 3.5 $\mu$m where the sky thermal background begins provide dominant...
Abstract With high equilibrium temperatures and tidally locked rotation, ultra-hot Jupiters (UHJs) are unique laboratories within which to probe extreme atmospheric physics chemistry. In this paper, we present high-resolution dayside spectroscopy of the UHJ WASP-189 b obtained with new Gemini High-resolution Optical SpecTrograph (GHOST) at South Observatory. The observations, cover 3 hr post-eclipse orbital phases, were during instrument’s System Verification run. We detect planet’s...
We present an investigation of the globular cluster population synthesis method McWilliam & Bernstein (2008), focusing on impact NLTE modeling effects and CMD discretization. Johnson-Cousins-Bessel U-B, B-V, V-I, J-K colors are produced for 96 synthetic integrated light spectra with two different discretization prescriptions three degrees treatment. These color values used to compare LTE derived ages. Relative contributions spectral types wavebands measured. Integrated shown be more luminous...
Spectra for two-dimensional (2D) stars in the 1.5D approximation are created from synthetic spectra of one-dimensional (1D) non-local thermodynamic equilibrium (NLTE) spherical model atmospheres produced by PHOENIX code. The have spatially averaged Rayleigh–Jeans flux a K3–4 III star while varying temperature difference between two 1D component models (ΔT1.5D) and relative surface area covered. Synthetic observable quantities fitted with NLTE local (LTE) to assess errors inferred Teff values...
Abstract We present an expanded investigation of the library globular cluster (GC) synthetic integrated light (IL) spectra Young & Short, focusing on impact non-local thermodynamic equilibrium (NLTE) modeling effects parameters derived from photometric colors and sensitivity near-IR spectral features to age metallicity. Johnson–Cousins–Bessel UBVIJK are produced for 910 IL with two degrees α enhancement, in both NLTE local (LTE). These color values used investigate GC age–metallicity...
Context. Several observational and theoretical results indicate that the atmospheric temperature of ultra-hot Jupiter KELT-9b in main line formation region is a few thousand degrees higher than predicted by self-consistent models. Aims. Our aim was to test whether non-local thermodynamic equilibrium (NLTE) effects are responsible for presumably temperature. Methods. We employed Cloudy NLTE radiative transfer code self-consistently compute upper temperature-pressure (TP) profile KELT-9b,...
We investigate the dependence of complete system 22 Lick indices on overall metallicity scaled from solar abundances, , value, 0.0, down to extremely metal-poor (XMP) value −6.0, for late-type giant stars (MK luminosity class III, ) MK spectral late-K late-F ( K) type that are detected as "fossils" early galaxy formation in Galactic halo and extra-galactic structures. Our investigation is based synthetic index values, I, derived atmospheric models spectra computed with PHOENIX Local...
With high equilibrium temperatures and tidally locked rotation, ultra-hot Jupiters (UHJs) are unique laboratories within which to probe extreme atmospheric physics chemistry. In this paper, we present high-resolution dayside spectroscopy of the UHJ WASP-189b obtained with new Gemini High-resolution Optical SpecTrograph (GHOST) at South Observatory. The observations, cover three hours post-eclipse orbital phases, were during instrument's System Verification run. We detect planet's atmosphere...
Nitrogen is a biosignature gas that cannot be maintained in its Earth‐like ratio with CO 2 under abiotic conditions. It has also been proven to notoriously hard detect at optical and infrared wavelengths. Fortunately, the ultraviolet region, which only recently started being explored for terrestrial exoplanets, may provide new opportunities characterize exoplanetary atmospheric nitrogen. In this work, future prospects detecting atomic nitrogen absorption lines transmission spectrum of an...
We aim at extracting the transmission spectrum of HI Balmer lines ultra-hot Jupiter (UHJ) KELT-20b/MASCARA-2b from observations and to further compare results with what obtained through forward modelling accounting for non-local thermodynamic equilibrium (NLTE) effects. extract line profiles six transits HARPS-N high-resolution spectrograph attached Telescopio Nazionale Galileo telescope. compute temperature-pressure (TP) profile employing helios code in lower atmosphere Cloudy NLTE middle...