scholarly journals Detection of Na in WASP-21b’s lower and upper atmosphere

2020 ◽  
Vol 642 ◽  
pp. A54 ◽  
Author(s):  
G. Chen ◽  
N. Casasayas-Barris ◽  
E. Pallé ◽  
L. Welbanks ◽  
N. Madhusudhan ◽  
...  
Keyword(s):  
Transmission Spectrum ◽  
Equilibrium Temperature ◽  
Low Resolution ◽  
Hot Jupiters ◽  
Transmission Spectroscopy ◽  
Alkali Atoms ◽  
Wide Range ◽  
Reference Pressure ◽  
Spectrally Resolved ◽  
Excess Absorption

Optical transmission spectroscopy provides crucial constraints on the reference pressure levels and scattering properties for the atmospheres of hot Jupiters. For certain planets, where alkali atoms are detected in the atmosphere, their line profiles could serve as a good probe to link upper and lower atmospheric layers. The planet WASP-21b is a Saturn-mass hot Jupiter orbiting a thick-disk star, with a low density and an equilibrium temperature of 1333 K, which makes it a good target for transmission spectroscopy. Here, we present a low-resolution transmission spectrum for WASP-21b based on one transit observed by the OSIRIS spectrograph at the 10.4 m Gran Telescopio Canarias (GTC), and a high-resolution transmission spectrum based on three transits observed by HARPS-N at Telescopio Nazinale Galileo (TNG) and HARPS at the ESO 3.6 m telescope. We performed spectral retrieval analysis on GTC’s low-resolution transmission spectrum and report the detection of Na at a confidence level of >3.5-σ. The Na line exhibits a broad line profile that can be attributed to pressure broadening, indicating a mostly clear planetary atmosphere. The spectrum shows a tentative excess absorption at the K D1 line. Using HARPS-N and HARPS, we spectrally resolved the Na doublet transmission spectrum. An excess absorption at the Na doublet is detected during the transit, and shows a radial velocity shift consistent with the planet orbital motion. We proposed a metric to quantitatively distinguish hot Jupiters with relatively clear atmospheres from others, and WASP-21b has the largest metric value among all the characterized hot Jupiters. The detection of Na both in the lower and upper atmospheres of WASP-21b reveals that it is an ideal target for future follow-up observations, providing the opportunity to understand the nature of its atmosphere across a wide range of pressure levels.

scholarly journals Detection of Na, K, and Hα absorption in the atmosphere of WASP-52b using ESPRESSO

2020 ◽  
Vol 635 ◽  
pp. A171 ◽  
Author(s):  
G. Chen ◽  
N. Casasayas-Barris ◽  
E. Pallé ◽  
F. Yan ◽  
M. Stangret ◽  
...  
Keyword(s):  
High Resolution ◽  
Transmission Spectrum ◽  
Orbital Motion ◽  
Telescope Array ◽  
Hot Jupiters ◽  
Velocity Shift ◽  
Very Large Telescope ◽  
Cloudy Atmosphere ◽  
Excess Absorption ◽  
Hot Jupiter

WASP-52b is a low-density hot Jupiter orbiting a moderately active K2V star. Previous low-resolution studies have revealed a cloudy atmosphere and found atomic Na above the cloud deck. Here we report on the detection of excess absorption at the Na doublet, the Hα line, and the K D1 line. We derived a high-resolution transmission spectrum based on three transits of WASP-52b, observed with the ultra-stable, high-resolution spectrograph ESPRESSO at the Very Large Telescope array. We measured a line contrast of 1.09 ± 0.16% for Na D1, 1.31 ± 0.13% for Na D2, 0.86 ± 0.13% for Hα, and 0.46 ± 0.13% for K D1, with a line FWHM range of 11–22 km s−1. We also found that the velocity shift of these detected lines during the transit is consistent with the planet’s orbital motion, thus confirming their planetary origin. We did not observe any significant net blueshift or redshift that could be attributed to planetary winds. We used activity indicator lines as control but found no excess absorption. However, we did notice signatures arising from the Center-to-Limb variation (CLV) and the Rossiter-McLaughlin (RM) effect at these control lines. This highlights the importance of the CLV + RM correction in correctly deriving the transmission spectrum, which, if not corrected, could resemble or cancel out planetary absorption in certain cases. WASP-52b is the second non-ultra-hot Jupiter to show excess Hα absorption after HD 189733b. Future observations targeting non-ultra-hot Jupiters that show Hα could help reveal the relation between stellar activity and the heating processes in the planetary upper atmosphere.

scholarly journals The atmosphere of WASP-76b seen with CARMENES: looking for CaII IRT and HeI

2021 ◽  
Author(s):  
Núria Casasayas-Barris ◽  
Jaume Orell-Miquel ◽  
Monika Stangret ◽  
Lisa Nortmann ◽  
Fei Yan ◽  
...  
Keyword(s):  
High Resolution ◽  
Transmission Spectrum ◽  
Potential Candidate ◽  
Hot Jupiters ◽  
Transmission Spectroscopy ◽  
Follow Up Studies ◽  
Ionised Calcium

<p>Currently, one of the most used techniques to study the atmosphere of the exoplanets is transmission spectroscopy by means of high-resolution facilities (R > 10<sup>5</sup>). This methodology has led to the detection of several species in the atmosphere of exoplanets, showing that ultra-hot Jupiters (T<sub>eq</sub> > 2000 K) are one of the most intriguing exoplanets, possessing the richest atmospheres measured to date. Here, using two transit observations with the high-resolution spectrograph CARMENES, we study the atmosphere of one of the most famous ultra-hot Jupiters: WASP-76b. We take advantage of the redder wavelength coverage of CARMENES, in comparison with the facilities used in previous studies of this same planet, and focus our analysis on the CaII IRT triplet at 850nm and the metastable HeI triplet at 1083nm. In line with recent studies, we detect ionised calcium in the atmosphere of WASP-76b and, additionally, find possible evidence of HeI. We contextualise our findings with previous atmospheric studies of other ultra-hot Jupiters and, in particular, with those showing the presence of CaII and HeI absorption in their transmission spectrum. We show that this planet is a potential candidate for further follow up studies of the HeI lines using high-resolution spectrographs located at larger telescopes, such as CRIRES+.</p>

scholarly journals Coupled day–night models of exoplanetary atmospheres

2020 ◽  
Vol 499 (4) ◽  
pp. 4984-5003
Author(s):  
Siddharth Gandhi ◽  
Adam S Jermyn
Keyword(s):  
General Circulation ◽  
General Circulation Models ◽  
Equilibrium Temperature ◽  
Relative Temperature ◽  
Thermal Inversion ◽  
Hot Jupiters ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Night Side ◽  
Exoplanetary Atmospheres

ABSTRACT We provide a new framework to model the day side and night side atmospheres of irradiated exoplanets using 1D radiative transfer by incorporating a self-consistent heat flux carried by circulation currents (winds) between the two sides. The advantages of our model are its physical motivation and computational efficiency, which allows for an exploration of a wide range of atmospheric parameters. We use this forward model to explore the day and night side atmosphere of WASP-76 b, an ultrahot Jupiter which shows evidence for a thermal inversion and Fe condensation, and WASP-43 b, comparing our model against high precision phase curves and general circulation models. We are able to closely match the observations as well as prior theoretical predictions for both of these planets with our model. We also model a range of hot Jupiters with equilibrium temperatures between 1000 and 3000 K and reproduce the observed trend that the day–night temperature contrast increases with equilibrium temperature up to ∼2500 K beyond which the dissociation of H2 becomes significant and the relative temperature difference declines.

scholarly journals The GTC exoplanet transit spectroscopy survey

2018 ◽  
Vol 609 ◽  
pp. A33 ◽  
Author(s):  
H. Parviainen ◽  
E. Pallé ◽  
G. Chen ◽  
L. Nortmann ◽  
F. Murgas ◽  
...  
Keyword(s):  
High Altitude ◽  
Transmission Spectrum ◽  
Rayleigh Scattering ◽  
Equilibrium Temperature ◽  
Transmission Spectra ◽  
Spectroscopy Analysis ◽  
Orbital Parameters ◽  
Transmission Spectroscopy ◽  
The Common ◽  
20 Nm

Aims. We set out to study the atmosphere of WASP-80b, a warm inflated gas giant with an equilibrium temperature of ~800 K, using ground-based transmission spectroscopy covering the spectral range from 520 to 910 nm. The observations allow us to probe the existence and abundance of K and Na in WASP-80b’s atmosphere, existence of high-altitude clouds, and Rayleigh-scattering in the blue end of the spectrum. Methods. We observed two spectroscopic time series of WASP-80b transits with the OSIRIS spectrograph installed in the Gran Telescopio Canarias (GTC), and use the observations to estimate the planet’s transmission spectrum between 520 nm and 910 nm in 20 nm-wide passbands, and around the K I and Na I resonance doublets in 6 nm-wide passbands. We jointly model three previously published broadband datasets consisting of 27 light curves, prior to a transmission spectroscopy analysis in order to obtain improved estimates of the planet’s orbital parameters, average radius ratio, and stellar density. The parameter posteriors from the broadband analysis are used to set informative priors on the transmission spectroscopy analysis. The final transmission spectroscopy analyses are carried out jointly for the two nights using a divide-by-white approach to remove the common-mode systematics, and Gaussian processes to model the residual wavelength-dependent systematics. Results. We recover a flat transmission spectrum with no evidence of Rayleigh scattering or K I or Na I absorption, and obtain an improved system characterisation as a by-product of the broadband- and GTC-dataset modelling. The transmission spectra estimated separately from the two observing runs are consistent with each other, as are the transmission spectra estimated using either a parametric or nonparametric systematics model. The flat transmission spectrum favours an atmosphere model with high-altitude clouds over cloud-free models with stellar or sub-stellar metallicities. Conclusions. Our results disagree with the recently published discovery of strong K I absorption in WASP-80b’s atmosphere based on ground-based transmission spectroscopy with FORS2 at VLT.

Colloidal Plasmonic Nanostar Antennas with Wide Range Resonance Tunability

2019 ◽  
Author(s):  
Theodoros Tsoulos ◽  
Supriya Atta ◽  
Maureen Lagos ◽  
Michael Beetz ◽  
Philip Batson ◽  
...  
Keyword(s):  
Single Particle ◽  
Structural Complexity ◽  
Field Enhancement ◽  
Hot Electron ◽  
Structure Property ◽  
Plasmon Band ◽  
Gold Nanostars ◽  
Wide Range ◽  
Particle Level ◽  
Spectrally Resolved

<div>Gold nanostars display exceptional field enhancement properties and tunable resonant modes that can be leveraged to create effective imaging tags or phototherapeutic agents, or to design novel hot-electron based photocatalysts. From a fundamental standpoint, they represent important tunable platforms to study the dependence of hot carrier energy and dynamics on plasmon band intensity and position. Toward the realization of these platforms, holistic approaches taking into account both theory and experiments to study the fundamental behavior of these</div><div>particles are needed. Arguably, the intrinsic difficulties underlying this goal stem from the inability to rationally design and effectively synthesize nanoparticles that are sufficiently monodispersed to be employed for corroborations of the theoretical results without the need of single particle experiments. Herein, we report on our concerted computational and experimental effort to design, synthesize, and explain the origin and morphology-dependence of the plasmon modes of a novel gold nanostar system, with an approach that builds upon the well-known plasmon hybridization model. We have synthesized monodispersed samples of gold nanostars with finely tunable morphology employing seed-mediated colloidal protocols, and experimentally observed narrow and spectrally resolved harmonics of the primary surface plasmon resonance mode both at the single particle level (via electron energy loss spectroscopy) and in ensemble (by UV-Vis and ATR-FTIR spectroscopies). Computational results on complex anisotropic gold nanostructures are validated experimentally on samples prepared colloidally, underscoring their importance as ideal testbeds for the study of structure-property relationships in colloidal nanostructures of high structural complexity.</div>

scholarly journals Detection of neutral atomic species in the ultra-hot Jupiter WASP-121b

2020 ◽  
Vol 494 (1) ◽  
pp. 363-377 ◽  
Author(s):  
Samuel H C Cabot ◽  
Nikku Madhusudhan ◽  
Luis Welbanks ◽  
Anjali Piette ◽  
Siddharth Gandhi
Keyword(s):  
High Resolution ◽  
Transmission Spectrum ◽  
Cross Correlation ◽  
Hydrogen Atmosphere ◽  
Chemical Processes ◽  
Thermal Inversion ◽  
Hot Jupiters ◽  
Roche Limit ◽  
Careful Treatment ◽  
Host Stars

ABSTRACT 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 their orbital and atmospheric properties. One such planet, WASP-121b, is in a highly misaligned orbit close to its Roche limit, and its atmosphere exhibits a thermal inversion. These properties make WASP-121b an interesting target for additional atmospheric characterization. In this paper, we present analyses of archival high-resolution optical spectra obtained during transits of WASP-121b. We model the Rossiter-McLaughlin effect and the Centre-to-Limb Variation and find that they do not significantly affect the transmission spectrum in this case. However, we discuss scenarios where these effects warrant more careful treatment by modelling the WASP-121 system and varying its properties. We report a new detection of atmospheric absorption from H α in the planet with a transit depth of $1.87\pm 0.11{{\ \rm per\ cent}}$. We further confirm a previous detection of the Na i doublet, and report a new detection of Fe i via cross-correlation with a model template. We attribute the H α absorption to an extended Hydrogen atmosphere, potentially undergoing escape, and the Fe i to equilibrium chemistry at the planetary photosphere. These detections help to constrain the composition and chemical processes in the atmosphere of WASP-121b.

scholarly journals Transfer of a Multiclass Method for over 60 Antibiotics in Food from High Resolution to Low Resolution Mass Spectrometry

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2935 ◽  
Author(s):  
Giusepponi ◽  
Paoletti ◽  
Barola ◽  
Moretti ◽  
Saluti ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
High Resolution ◽  
Development Process ◽  
Tandem Mass ◽  
Laboratory Studies ◽  
Low Resolution ◽  
Method Transfer ◽  
Wide Range ◽  
Microbial Residues

A multiclass method has been developed to screen and confirm a wide range of anti-microbial residues in muscle and milk, and validated using liquid-chromatography coupled to (low-resolution, LR) tandem mass spectrometry (LC-QqQ). Over sixty antibiotics, belonging to ten distinct families, were included in the method scope. The development process was rapidly concluded as a result of two previously implemented methods. This consisted of identical sample treatments, followed by liquid chromatography, and coupled with high-resolution (HR) mass spectrometry (LC-Q-Orbitrap). The validation study was performed in the range between 10–1500 μg·kg−1 for muscles and 2–333 μg·kg−1 for milk. The main performance characteristics were estimated and, then, compared to those previously obtained with HR technique. The validity of the method transfer was ascertained also through inter-laboratory studies.

scholarly journals Molecular cross-sections for high-resolution spectroscopy of super-Earths, warm Neptunes, and hot Jupiters

2020 ◽  
Vol 495 (1) ◽  
pp. 224-237 ◽  
Author(s):  
Siddharth Gandhi ◽  
Matteo Brogi ◽  
Sergei N Yurchenko ◽  
Jonathan Tennyson ◽  
Phillip A Coles ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Sections ◽  
Cross Correlation ◽  
High Resolution Spectroscopy ◽  
High Signal ◽  
Pressure Broadening ◽  
Spectral Signatures ◽  
Hot Jupiters ◽  
Wide Range ◽  
Infrared Spectral

ABSTRACT High-resolution spectroscopy (HRS) has been used to detect a number of species in the atmospheres of hot Jupiters. Key to such detections is accurately and precisely modelled spectra for cross-correlation against the R ≳ 20 000 observations. There is a need for the latest generation of opacities which form the basis for high signal-to-noise detections using such spectra. In this study we present and make publicly available cross-sections for six molecular species, H2O, CO, HCN, CH4, NH3, and CO2 using the latest line lists most suitable for low- and high-resolution spectroscopy. We focus on the infrared (0.95–5 μm) and between 500 and 1500 K where these species have strong spectral signatures. We generate these cross-sections on a grid of pressures and temperatures typical for the photospheres of super-Earth, warm Neptunes, and hot Jupiters using the latest H2 and He pressure broadening. We highlight the most prominent infrared spectral features by modelling three representative exoplanets, GJ 1214 b, GJ 3470 b, and HD 189733 b, which encompass a wide range in temperature, mass, and radii. In addition, we verify the line lists for H2O, CO, and HCN with previous high-resolution observations of hot Jupiters. However, we are unable to detect CH4 with our new cross-sections from HRS observations of HD 102195 b. These high-accuracy opacities are critical for atmospheric detections with HRS and will be continually updated as new data become available.

scholarly journals ISO Observations of AGN and Ultraluminous IR Galaxies

1998 ◽  
Vol 11 (2) ◽  
pp. 1131-1133 ◽  
Author(s):  
Alan F. M. Moorwood
Keyword(s):  
Ionization Potential ◽  
Elliptical Galaxy ◽  
Emission Lines ◽  
Spectral Energy ◽  
High Excitation ◽  
Low Resolution ◽  
Energy Distributions ◽  
Diagnostic Features ◽  
Wide Range ◽  
First Time

All the ISO instruments are contributing to the study of activity in galaxies of essentially all types. Although AGN's as such are pointlike, the beautiful CAM image of CenA shown by Catherine Cesarsky has given us the clearest view so far of its visually obscured nucleus and surrounding spiral disc embedded in an elliptical galaxy. The CAM CVF is also providing spectral images of the PAH features and important diagnostic ionic lines (e.g [NeII] and [NeIII]) in the circumnuclar regions of AGN and merging starburst systems (Vigroux et al., 1996). PHT is providing detailed spectral energy distributions over the complete 2.5-240µm range and PHTS is proving invaluable for assembling a catalogue of low resolution (R ⋍ 90) galaxy spectra covering the 6-12µm PAH features. SWS and LWS are generating higher resolution (R ⋍ 2000-200) spectra over the range 2.5-200µm such as that shown in Fig. 1. of the Circinus galaxy which exhibits both AGN and starburst activity and well illustrates the wide range of diagnostic features, many seen for the first time, accessible to ISO studies of galaxies. It shows the overall continuum with a peak around 100µm; PAH features and Si absorption which dominate the spectrum around 10µm; H recombination lines; H2 pure rotational emission lines; low ionization potential ionic lines excited by starburst activity and high excitation lines (up to ⋍ 300eV) excited by the visually obscured AGN.

scholarly journals Evaluating seasonal hydrological extremes in mesoscale (pre-)Alpine basins at coarse 0.5° and fine hyperresolution

2019 ◽  
Vol 23 (3) ◽  
pp. 1593-1609 ◽  
Author(s):  
Joost Buitink ◽  
Remko Uijlenhoet ◽  
Adriaan J. Teuling
Keyword(s):  
High Resolution ◽  
Land Cover ◽  
Swiss Alps ◽  
Hydrological Response ◽  
Low Resolution ◽  
Continental Scale ◽  
Wide Range ◽  
Resolution Model ◽  
High Resolution Model ◽  
Basin Response

Abstract. Hydrological models are being applied for impact assessment across a wide range of resolutions. In this study, we quantify the effect of model resolution on the simulated hydrological response in five mesoscale basins in the Swiss Alps using the distributed hydrological model Spatial Processes in Hydrology (SPHY). We introduce a new metric to compare a range of values resulting from a distributed model with a single value: the density-weighted distance (DWD). Model simulations are performed at two different spatial resolutions, matching common practices in hydrology: 500 m × 500 m matching regional-scale models, and 40 km × 40 km matching global-scale modeling. We investigate both the intra-basin response in seasonal streamflow and evapotranspiration from the high-resolution model and the difference induced by the two different spatial resolutions, with a focus on four seasonal extremes, selected based on temperature and precipitation. Results from the high-resolution model show that the intra-basin response covers a surprisingly large range of anomalies and show that it is not uncommon to have both extreme positive and negative flux anomalies occurring simultaneously within a catchment. The intra-basin response was grouped by land cover, where different dominant runoff-generating processes are driving the differences between these groups. The low-resolution model failed to capture the diverse and contrasting response from the high-resolution model, since neither the complex topography nor land cover classes were properly represented. DWD values show that, locally, the hydrological response simulated with a high-resolution model can be a lot more extreme than a low-resolution model might indicate, which has important implications for global or continental scale assessments carried out at coarse grids of 0.5∘×0.5∘ or 0.25∘×0.25∘ resolution.

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