scholarly journals Spatial characterization of the trailing and leading limbs of WASP-76b: Detection of H2O and HCN at high-resolution

2021 ◽  
Author(s):  
Alejandro Sánchez López ◽  
Rico Landman ◽  
Núria Casasayas Barris ◽  
Aurora Kesseli ◽  
Ignas Snellen
Keyword(s):  
High Resolution ◽  
Extreme Temperature ◽  
Temporal Variations ◽  
Time Variability ◽  
Small Range ◽  
Hot Jupiters ◽  
Spatial Characterization ◽  
Weak Evidence ◽  
Dependent Absorption

<p class="p1">Extreme temperature contrasts between the day and nightside of ultra-hot Jupiters (UHJ) result in significantly asymmetric atmospheres, with a region of extreme atmospheric expansion appearing over a small range of latitudes around the terminator. Over the course of a transit, WASP-76 b rotates by about 30° and hence temporal variations of the observable atmosphere could significantly affect the detectability of its constituents. Specifically, the trailing limb of this planet allows us to probe a significant portion of the inflated dayside, resulting in a higher atmospheric detectability. This geometric effect could mimic the observed time-variability of absorption signals due to condensation in the nightside of these planets, which has been recently reported for neutral iron in WASP-76 b. By studying molecules that are not expected to condense in the nightside of UHJs (~1000K), we can isolate the possible effect of different day and nightside scale heights. Here, we will analyze a stronger water vapor signal during the egress of the planet than at ingress, which cannot be explained by condensation and suggests that the extreme geometry of UHJ manifests itself as time-dependent absorption signals. Additionally, we report a redshifted HCN signature arising from the leading limb (i.e., observable in the first half of the transit and absent from the second half) and a weak evidence of ammonia using high-resolution observations of WASP-76 b with CARMENES.</p>

scholarly journals petitRADTRANS

2019 ◽  
Vol 627 ◽  
pp. A67 ◽  
Author(s):  
P. Mollière ◽  
J. P. Wardenier ◽  
R. van Boekel ◽  
Th. Henning ◽  
K. Molaverdikhani ◽  
...  
Keyword(s):  
High Resolution ◽  
Optical Constants ◽  
Emission Spectra ◽  
Transmission Spectra ◽  
Low Resolution ◽  
Cloud Particle ◽  
Hot Jupiters ◽  
Higher Temperature ◽  
Python Package

We present the easy-to-use, publicly available, Python package petitRADTRANS, built for the spectral characterization of exoplanet atmospheres. The code is fast, accurate, and versatile; it can calculate both transmission and emission spectra within a few seconds at low resolution (λ/Δλ = 1000; correlated-k method) and high resolution (λ/Δλ = 106; line-by-line method), using only a few lines of input instruction. The somewhat slower, correlated-k method is used at low resolution because it is more accurate than methods such as opacity sampling. Clouds can be included and treated using wavelength-dependent power law opacities, or by using optical constants of real condensates, specifying either the cloud particle size, or the atmospheric mixing and particle settling strength. Opacities of amorphous or crystalline, spherical or irregularly-shaped cloud particles are available. The line opacity database spans temperatures between 80 and 3000 K, allowing to model fluxes of objects such as terrestrial planets, super-Earths, Neptunes, or hot Jupiters, if their atmospheres are hydrogen-dominated. Higher temperature points and species will be added in the future, allowing to also model the class of ultra hot-Jupiters, with equilibrium temperatures Teq ≳ 2000 K. Radiative transfer results were tested by cross-verifying the low- and high-resolution implementation of petitRADTRANS, and benchmarked with the petitCODE, which itself is also benchmarked to the ATMO and Exo-REM codes. We successfully carried out test retrievals of synthetic JWST emission and transmission spectra (for the hot Jupiter TrES-4b, which has a Teq of ∼1800 K).

scholarly journals Spatial Characterization of MAC, a High-Resolution Optical Earth Observation Camera for Small Satellites

2005 ◽  
Vol 9 (2) ◽  
pp. 79-83 ◽  
Author(s):  
Eugene D. Kim ◽  
Young-Wan Choi ◽  
Ho-Soon Yang ◽  
Mohd. Afiq bin Ismail
Keyword(s):  
High Resolution ◽  
Earth Observation ◽  
Small Satellites ◽  
Spatial Characterization

High-resolution spatial characterization of laser produced plasmas at soft x-ray wavelengths

2004 ◽  
Vol 78 (1) ◽  
pp. 53-58 ◽  
Author(s):  
U. Vogt ◽  
R. Frueke ◽  
T. Wilhein ◽  
H. Stollberg ◽  
P.A.C. Jansson ◽  
...  
Keyword(s):  
High Resolution ◽  
X Ray ◽  
Spatial Characterization

Cold-seep habitat mapping: High-resolution spatial characterization of the Blake Ridge Diapir seep field

2013 ◽  
Vol 92 ◽  
pp. 183-188 ◽  
Author(s):  
Jamie K.S. Wagner ◽  
Molly H. McEntee ◽  
Laura L. Brothers ◽  
Christopher R. German ◽  
Carl L. Kaiser ◽  
...  
Keyword(s):  
High Resolution ◽  
Habitat Mapping ◽  
Cold Seep ◽  
Spatial Characterization ◽  
Blake Ridge

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

High-resolution electron microscopy of nanostructured materials

1995 ◽  
Vol 53 ◽  
pp. 172-173
Author(s):  
M. José-Yacamán
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Nanostructured Materials ◽  
High Resolution Electron Microscopy ◽  
Hrem Image ◽  
Small Particles ◽  
Resolution Electron ◽  
Nanophase Materials

Electron microscopy is a fundamental tool in materials characterization. In the case of nanostructured materials we are looking for features with a size in the nanometer range. Therefore often the conventional TEM techniques are not enough for characterization of nanophases. High Resolution Electron Microscopy (HREM), is a key technique in order to characterize those materials with a resolution of ~ 1.7A. High resolution studies of metallic nanostructured materials has been also reported in the literature. It is concluded that boundaries in nanophase materials are similar in structure to the regular grain boundaries. That work therefore did not confirm the early hipothesis on the field that grain boundaries in nanostructured materials have a special behavior. We will show in this paper that by a combination of HREM image processing, and image calculations, it is possible to prove that small particles and coalesced grains have a significant surface roughness, as well as large internal strain.

High-resolution transmission electron microscopic study of highly oxygen doped silicon layer

1989 ◽  
Vol 47 ◽  
pp. 692-693
Author(s):  
H. Takaoka ◽  
M. Tomita ◽  
T. Hayashi
Keyword(s):  
High Resolution ◽  
Oxygen Concentration ◽  
Silicon Layer ◽  
Detailed Structure ◽  
Electron Microscopic ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Doped Silicon ◽  
Argon Ion

High resolution transmission electron microscopy (HRTEM) is the effective technique for characterization of detailed structure of semiconductor materials. Oxygen is one of the important impurities in semiconductors. Detailed structure of highly oxygen doped silicon has not clearly investigated yet. This report describes detailed structure of highly oxygen doped silicon observed by HRTEM. Both samples prepared by Molecular beam epitaxy (MBE) and ion implantation were observed to investigate effects of oxygen concentration and doping methods to the crystal structure.The observed oxygen doped samples were prepared by MBE method in oxygen environment on (111) substrates. Oxygen concentration was about 1021 atoms/cm3. Another sample was silicon of (100) orientation implanted with oxygen ions at an energy of 180 keV. Oxygen concentration of this sample was about 1020 atoms/cm3 Cross-sectional specimens of (011) orientation were prepared by argon ion thinning and were observed by TEM at an accelerating voltage of 400 kV.

HRTEM simulation of interfacial structure in amorphous multilayers

1989 ◽  
Vol 47 ◽  
pp. 466-467
Author(s):  
Margaret L. Sattler ◽  
Michael A. O'Keefe
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Cross Section ◽  
High Resolution Electron Microscopy ◽  
Interfacial Structure ◽  
Multilayer Sample ◽  
Resolution Electron ◽  
Multilayered Materials ◽  
Simulated Images

Multilayered materials have been fabricated with such high perfection that individual layers having two atoms deep are possible. Characterization of the interfaces between these multilayers is achieved by high resolution electron microscopy and Figure 1a shows the cross-section of one type of multilayer. The production of such an image with atomically smooth interfaces depends upon certain factors which are not always reliable. For example, diffusion at the interface may produce complex interlayers which are important to the properties of the multilayers but which are difficult to observe. Similarly, anomalous conditions of imaging or of fabrication may occur which produce images having similar traits as the diffusion case above, e.g., imaging on a tilted/bent multilayer sample (Figure 1b) or deposition upon an unaligned substrate (Figure 1c). It is the purpose of this study to simulate the image of the perfect multilayer interface and to compare with simulated images having these anomalies.

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