Jayesh Goyal
A5006133836- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- Astronomical Observations and Instrumentation
- Geophysics and Gravity Measurements
- Spacecraft and Cryogenic Technologies
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- Meteorological Phenomena and Simulations
- Scientific Research and Discoveries
- Astronomical and nuclear sciences
- Spacecraft Design and Technology
- Adaptive optics and wavefront sensing
- Cosmology and Gravitation Theories
- Planetary Science and Exploration
- CCD and CMOS Imaging Sensors
- Atmospheric chemistry and aerosols
- Spectroscopy Techniques in Biomedical and Chemical Research
- Pulsars and Gravitational Waves Research
- Atmospheric aerosols and clouds
- Blind Source Separation Techniques
- Inertial Sensor and Navigation
National Institute of Science Education and Research
2021-2025
University of California, Irvine
2024
Cornell University
2020-2023
Homi Bhabha National Institute
2022-2023
University of Exeter
2016-2023
Indian Institute of Science Bangalore
2017
We present a new set of solar metallicity atmosphere and evolutionary models for very cool brown dwarfs self-luminous giant exoplanets, which we term ATMO 2020. Atmosphere are generated with our state-of-the-art 1D radiative-convective equilibrium code ATMO, used as surface boundary conditions to calculate the interior structure evolution $0.001-0.075\,\mathrm{M_{\odot}}$ objects. Our include several key improvements input physics in previous available literature. Most notably, use H-He...
Transmission spectroscopy1-3 of exoplanets has revealed signatures water vapour, aerosols and alkali metals in a few dozen exoplanet atmospheres4,5. However, these previous inferences with the Hubble Spitzer Space Telescopes were hindered by observations' relatively narrow wavelength range spectral resolving power, which precluded unambiguous identification other chemical species-in particular primary carbon-bearing molecules6,7. Here we report broad-wavelength 0.5-5.5 µm atmospheric...
WASP-39b is a hot Saturn-mass exoplanet with predicted clear atmosphere based on observations in the optical and infrared. Here we complete transmission spectrum of near-infrared (NIR) over three water absorption features Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) G102 (0.8-1.1 microns) G141 (1.1-1.7 spectroscopic grisms. We measure high amplitude H2O feature centered at 1.4 microns, smaller 0.95 1.2 maximum 2.4 planetary scale heights. incorporate these new NIR measurements...
Measuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking formation evolution exoplanetary systems. Access to an exoplanet's chemical inventory requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based high-resolution ground-based facilities. Here we report medium-resolution (R$\sim$600) transmission spectrum atmosphere between 3-5 $\mu$m covering multiple absorption...
Transmission spectroscopy provides insight into the atmospheric properties and consequently formation history, physics, chemistry of transiting exoplanets. However, obtaining precise inferences from transmission spectra requires simultaneously measuring strength shape multiple spectral absorption features a wide range chemical species. This has been challenging given precision wavelength coverage previous observatories. Here, we present spectrum Saturn-mass exoplanet WASP-39b obtained using...
Abstract Carbon dioxide (CO 2 ) is a key chemical species that found in wide range of planetary atmospheres. In the context exoplanets, CO an indicator metal enrichment (that is, elements heavier than helium, also called ‘metallicity’) 1–3 , and thus formation processes primary atmospheres hot gas giants 4–6 . It one most promising to detect secondary terrestrial exoplanets 7–9 Previous photometric measurements transiting planets with Spitzer Space Telescope have given hints presence but not...
Photochemistry is a fundamental process of planetary atmospheres that regulates the atmospheric composition and stability. However, no unambiguous photochemical products have been detected in exoplanet to date. Recent observations from JWST Transiting Exoplanet Early Release Science Program found spectral absorption feature at 4.05 $\mu$m arising SO$_2$ atmosphere WASP-39b. WASP-39b 1.27-Jupiter-radii, Saturn-mass (0.28 M$_J$) gas giant orbiting Sun-like star with an equilibrium temperature...
Abstract Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet atmospheres is a fundamental step towards constraining dominant chemical processes at work and, if equilibrium, revealing planet formation histories. Transmission spectroscopy (for example, refs. 1,2 ) provides necessary means by abundances of oxygen- carbon-bearing species; however, this requires broad wavelength coverage, moderate spectral resolution high precision, which, together, are not achievable with...
Abstract Close-in giant exoplanets with temperatures greater than 2,000 K (‘ultra-hot Jupiters’) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from Hubble Space Telescope (HST) and Spitzer 1–3 . However, previous studies yielded inconsistent results because small sizes spectral features limited information content data resulted in high sensitivity varying assumptions made treatment instrument systematics retrieval...
Abstract Clouds are prevalent in many of the exoplanet atmospheres that have been observed to date. For transiting exoplanets, we know if clouds present because they mute spectral features and cause wavelength-dependent scattering. While exact composition these is largely unknown, this information vital understanding chemistry energy budget planetary atmospheres. In work, observe one transit hot Jupiter WASP-17b with JWST’s Mid-Infrared Instrument Low Resolution Spectrometer generate a...
The James Webb Space Telescope (JWST) presents the opportunity to transform our understanding of planets and origins life by revealing atmospheric compositions, structures, dynamics transiting exoplanets in unprecedented detail. However, high-precision, timeseries observations required for such investigations have unique technical challenges, prior experience with Hubble, Spitzer, other facilities indicates that there will be a steep learning curve when JWST becomes operational. In this...
We present a grid of forward model transmission spectra, adopting an isothermal temperature-pressure profile, alongside corresponding equilibrium chemical abundances for 117 observationally significant hot exoplanets (equilibrium temperatures 547–2710 K). This has been developed using 1D radiative–convective–chemical termed ATMO, with up-to-date high-temperature opacities. interpretation observations 10 exoplanets, including best-fitting parameters and χ2 maps. In agreement previous works,...
To understand and compare the 3D atmospheric structure of HD 209458 b 189733 b, focusing on formation distribution cloud particles, as well their feedback dynamics thermal profile. We couple Met Office Unified Model (UM), including detailed treatments radiative transfer dynamics, to a kinetic scheme. The resulting model self--consistently solves for condensation seeds, surface growth evaporation, gravitational settling advection, via absorption and, crucially, scattering. Fluxes directly...
Abstract Transmission spectroscopy is a powerful technique widely used to probe exoplanet terminators. Atmospheric retrievals of transmission spectra are enabling comparative studies atmospheres. However, the atmospheric properties inferred by retrieval techniques display significant anomaly: most retrieved temperatures far colder than expected. In some cases, . Here, we provide an explanation for this conundrum. We demonstrate that erroneously cold result when 1D models applied planets with...
In this work we investigate the impact of calculating non-equilibrium chemical abundances consistently with temperature structure for atmospheres highly-irradiated, close-in gas giant exoplanets. Chemical kinetics models have been widely used in literature to compositions hot Jupiter which are expected be driven away from equilibrium via processes such as vertical mixing and photochemistry. All these so far pressure--temperature (P-T) profiles fixed model input. This results a decoupling...
The temperature profile of a planetary atmosphere is key diagnostic radiative and dynamical processes governing the absorption, redistribution, emission energy. Observations have revealed dayside stratospheres that either cool or warm with altitude for small number gas giant exoplanets, while other are consistent constant temperatures. Here we report spectroscopic phase curve measurements WASP-121b, which constrain stratospheric temperatures throughout diurnal cycle. Variations measured...
The future is now - after its long-awaited launch in December 2021, JWST began science operations July 2022 and already revolutionizing exoplanet astronomy. Early Release Observations (ERO) program was designed to provide the first images spectra from JWST, covering a multitude of cases using multiple modes each on-board instrument. Here, we present transmission spectroscopy observations hot-Saturn WASP-96b with Single Object Slitless Spectroscopy (SOSS) mode Near Infrared Imager...
We present the first exoplanet phase curve measurement made with JWST NIRSpec instrument, highlighting exceptional stability of this newly-commissioned observatory for climate studies. The target, WASP-121b, is an ultrahot Jupiter orbital period 30.6 hr. analyze two broadband light curves generated NRS1 and NRS2 detectors, covering wavelength ranges 2.70-3.72 micron 3.82-5.15 micron, respectively. Both exhibit minimal systematics, approximately linear drifts in baseline flux level 30 ppm/hr...
Abstract We present the first emission spectrum of hot Jupiter WASP-17 b using one eclipse observation from JWST Near Infrared Imager and Slitless Spectrograph (NIRISS) Single Object Spectroscopy (SOSS) mode. Covering a wavelength range 0.6–2.8 μ m, our retrieval analysis reveals strong detection H 2 O in b’s dayside atmosphere (6.4 σ ). Our retrievals consistently favor supersolar abundance noninverted temperature–pressure profile over large pressure range. Additionally, examination...
WASP-121b is a transiting gas giant exoplanet orbiting close to its Roche limit, with an inflated radius nearly double that of Jupiter and dayside temperature comparable late M dwarf photosphere. Secondary eclipse observations covering the 1.1-1.6 micron wavelength range have revealed atmospheric thermal inversion on hemisphere, likely caused by high altitude absorption at optical wavelengths. Here we present secondary made Hubble Space Telescope Wide Field Camera 3 spectrograph extend...
Abstract We present an atmospheric transmission spectrum for the ultra-hot Jupiter WASP-121b, measured using Space Telescope Imaging Spectrograph on board Hubble . Across 0.47–1 <?CDATA $\mu {\rm{m}}$?> wavelength range, data imply opacity comparable to—and in some spectroscopic channels exceeding—that previously at near-infrared wavelengths (1.15–1.65 ). Wavelength-dependent variations rule out a gray cloud deck confidence level of 3.7 σ and may instead be explained by VO spectral bands....
We present results of simulations the climate newly discovered planet Proxima Centauri B, performed using Met Office Unified Model (UM). examine responses both an `Earth-like' atmosphere and simplified nitrogen trace carbon dioxide to radiation likely received by B. Additionally, we explore effects orbital eccentricity on planetary conditions a range eccentricities guided observational constraints. Overall, our are in agreement with previous studies suggesting B may well have surface...