scholarly journals Searching for thermal inversion agents in the transmission spectrum of KELT-20b/MASCARA-2b: detection of neutral iron and ionised calcium H&K lines

2020 ◽  
Vol 496 (1) ◽  
pp. 504-522 ◽  
Author(s):  
Stevanus K Nugroho ◽  
Neale P Gibson ◽  
Ernst J W de Mooij ◽  
Chris A Watson ◽  
Hajime Kawahara ◽  
...  
Keyword(s):  
Chemical Equilibrium ◽  
Inversion Layer ◽  
Mapping Method ◽  
Cold Trap ◽  
Mapping Technique ◽  
Thermal Inversion ◽  
Double Peak Structure ◽  
Peak Structure ◽  
Solar Metallicity ◽  
Likelihood Mapping

ABSTRACT We analyse the transmission spectra of KELT-20b/MASCARA-2b to search for possible thermal inversion agents. The data consist of three transits obtained using HARPSN and one using CARMENES. We removed stellar and telluric lines before cross-correlating the residuals with spectroscopic templates produced using a 1D plane-parallel model, assuming an isothermal atmosphere and chemical equilibrium at solar metallicity. Using a likelihood-mapping method, we detect Fe i at > 13σ, Ca ii H$\&$K at > 6σ and confirm the previous detections of Fe ii, Ca ii IR Triplet, and Na i D. The detected signal of Fe i is shifted by −3.4 ± 0.4 km s−1 from the planetary rest frame, which indicates a strong day–night wind. Our likelihood-mapping technique also reveals that the absorption features of the detected species extend to different altitudes in the planet’s atmosphere. Assuming that the line lists are accurate, we do not detect other potential thermal inversion agents (NaH, MgH, AlO, SH, CaO, VO, FeH, and TiO) suggesting that non-chemical equilibrium mechanisms (e.g. a cold-trap) might have removed Ti- and V-bearing species from the upper atmosphere. Our results, therefore, show that KELT-20b/MASCARA-2b cannot possess an inversion layer caused by a TiO/VO-related mechanism. The presence of an inversion layer would therefore likely be caused by metal atoms such as Fe i and Fe ii. Finally, we report a double-peak structure in the Fe i signal in all of our data sets that could be a signature of atmospheric dynamics. However, further investigation is needed to robustly determine the origin of the signal.

Triply Differential Positron and Electron Impact Ionization of Argon: Systematic Features and Scaling

Atoms ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 78
Author(s):  
R. D. DuBois ◽  
O. G. de Lucio
Keyword(s):  
Momentum Transfer ◽  
Electron Impact ◽  
Impact Ionization ◽  
Emission Angle ◽  
Electron Impact Ionization ◽  
Charge Effects ◽  
Double Peak Structure ◽  
Peak Structure ◽  
Momentum Transfer Range ◽  
Projectile Charge

Triply differential data are presented for the 200 eV positron and electron impact ionization of argon. Six electron emission energies between 2.6 and 19 eV, and for scattering angles of 2, 3, and 4 degrees cover a momentum transfer range of 0.16 to 0.31 a.u. The binary and recoil intensities are fitted using a double peak structure in both regions, which, for the present kinematic conditions, are unresolved. The fitted peak intensities and angular positions are shown to have systematic dependences as a function of the momentum transfer and kinematic emission angle, respectively, and illustrate projectile charge effects. A comparison with available theories is made where it is seen that the most notable differences include the fact that for the binary lobe, the observed intensity for emission angles around 100° is absent in the theories, and the theoretical predications overestimate the importance of recoil interactions.

scholarly journals Differences between coastal and open ocean distributions of N<sub>2</sub>O in the oxygen minimum zone off Peru

2015 ◽  
Vol 12 (13) ◽  
pp. 10167-10193 ◽  
Author(s):  
A. Kock ◽  
D. L. Arévalo-Martínez ◽  
C. R. Löscher ◽  
H. W. Bange
Keyword(s):  
Linear Relationship ◽  
Coastal Upwelling ◽  
Oxygen Minimum Zone ◽  
Open Ocean ◽  
Oxygen Utilization ◽  
Double Peak Structure ◽  
Peak Structure ◽  
Minimum Zone ◽  
Oxygen Minimum ◽  
Oxygen Concentrations

Abstract. Depth profiles of nitrous oxide (N2O) were measured during six cruises to the upwelling area and oxygen minimum zone (OMZ) off Peru in 2009 and 2012/13, covering both the coastal shelf region and the adjacent open ocean. N2O profiles displayed a strong sensitivity towards oxygen concentrations. Open ocean profiles showed a transition from a broad maximum to a double-peak structure towards the centre of the OMZ where the oxygen minimum was more pronounced. Maximum N2O concentrations in the open ocean were about 80 nM. A linear relationship between ΔN2O and apparent oxygen utilization (AOU) could be found for all measurements within the upper oxycline, with a slope similar to studies in other oceanic regions. N2O profiles close to the shelf revealed a much higher variability, with N2O concentrations in the upper oxycline reaching up to several hundred nanomoles per liter at selected stations. Due to the extremely sharp oxygen gradients at the shelf, these maxima occurred in very shallow water depths of less than 50 m. In this area, a linear relationship between ΔN2O and AOU could not be observed. N2O concentrations above 100 nM were observed at oxygen concentrations ranging from close to saturation to suboxic conditions. Our results indicate that the coastal upwelling off Peru at the shelf causes conditions that lead to extreme N2O accumulation.

scholarly journals Methodology for determining multilayered temperature inversions

2014 ◽  
Vol 7 (10) ◽  
pp. 10559-10583 ◽  
Author(s):  
G. J. Fochesatto
Keyword(s):  
Temperature Profile ◽  
Large Scale ◽  
Thermal Structure ◽  
Error Function ◽  
Inversion Layer ◽  
Meteorological Forcing ◽  
Temperature Variations ◽  
Thermal Inversion ◽  
Upper Level ◽  
Temperature Inversions

Abstract. The atmospheric boundary layer (ABL) exhibit multilayered thermal structure especially in polar atmosphere during extreme winters. These thermal inversions are originated based on the combined forcing of local and large scale synoptic meteorology. At the local scale the thermal inversion layer forms near the surface and plays a central role in controlling the surface radiative cooling; however, depending upon the large scale synoptic meteorological forcing, an upper level thermal inversion can also exist topping the local ABL. In this article a numerical methodology is developed to determine all-thermal inversion layers present in a given temperature profile and deduce some of their thermodynamic properties. The algorithm extract from the temperature profile the most important temperature variations defining thermal layers. This is accomplished by a inear interpolation function of variable length that minimizes an error function. The algorithm functionality is demonstrated on actual radiosonde profiles to deduce all-present inversion layers with an error fraction set independently.

scholarly journals Mapping technique of climate fields between GCM's and ice models

2010 ◽  
Vol 3 (1) ◽  
pp. 13-41 ◽  
Author(s):  
T. J. Reerink ◽  
M. A. Kliphuis ◽  
R. S. W. van de Wal
Keyword(s):  
General Circulation ◽  
Climate Model ◽  
Circulation Model ◽  
Mapping Method ◽  
Mapping Technique ◽  
Oblique Projection ◽  
Surface Mass ◽  
Opposite Case ◽  
Average Temperature ◽  
Community System

Abstract. Here, we present a mapping method OBLIMAP, which projects and interpolates fields like surface temperature, surface mass balance, and surface height between a geographical based coordinate system of a General Circulation Model (GCM) and a rectangular based Ice Model (IM). We derive an oblique stereographic projection and its inverse, which holds for any area at the Earth's surface, and which can be combined with two different interpolation methods. The first one is suited to interpolate the projected fields of a coarse GCM grid on a fine meshed IM grid. The second one is appropriate for the opposite case. Both grids are allowed to be arbitrary and irregularly spaced. Therefore the OBLIMAP technique is suitable for any GCM-IM combination. After a first scan of the GCM grid coordinates and the specification of the IM grid, fast mapping of various fields is possible. To and fro (GCM-IM-GCM) mapping tests with the Climate Community System Model (CCSM) at T42 resolution (~313 km) and the Regional Atmospheric Climate Model (RACMO) at ~11 km and ~55 km, show average temperature differences of less than 0.1 K with small standard deviations. OBLIMAP, available at GMD, is an accurate, robust and well-documented mapping method for coupling an IM with a GCM or to map state of the art initial and forcing fields available at geographical coordinates to any local IM grid with an optimal centered oblique projection. Currently, the oblique stereographic and the oblique Lambert azimuthal equal-area projections for both the sphere and the ellipsoid are implemented in OBLIMAP.

The magnetocaloric effect with critical behavior of a periodic Anderson-like organic polymer

2016 ◽  
Vol 18 (1) ◽  
pp. 510-518 ◽  
Author(s):  
L. J. Ding ◽  
Y. Zhong ◽  
S. W. Fan ◽  
L. Y. Zhu
Keyword(s):  
Critical Behavior ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Organic Polymer ◽  
Magnetic Entropy ◽  
Cooling Process ◽  
Double Peak ◽  
Double Peak Structure ◽  
Peak Structure ◽  
Magnetic Cooling

The magnetic entropy change (−ΔS) shows a double-peak structure, indicating a double magnetic cooling process via demagnetization.

scholarly journals Pressure Wave in Liquid Generated by Pneumatic Pistons and Its Interaction with a Free Surface

2017 ◽  
Vol 09 (03) ◽  
pp. 1750037 ◽  
Author(s):  
Victoria Suponitsky ◽  
David Plant ◽  
Eldad J. Avital ◽  
Ante Munjiza
Keyword(s):  
Free Surface ◽  
Pressure Wave ◽  
Equations Of State ◽  
Current System ◽  
Nonlinear Effects ◽  
Compression Process ◽  
Double Peak Structure ◽  
Peak Structure ◽  
Westervelt Equation ◽  
The Difference

Numerical analysis of a pressure wave generated in a liquid [Formula: see text] upon impact of the pneumatic pistons and its interaction with a free surface has been performed for the geometry and parameters of the plasma compression system prototype constructed by General Fusion Inc. Stress wave developing in the hammer–anvil piston assembly is first simulated using high-fidelity structural mechanics research code, then propagated through the liquid [Formula: see text] with several solvers within OpenFOAM[Formula: see text] software and also with nonlinear acoustics in-house code based on the Westervelt equation. In the current system, a pressure wave transmitted into the liquid [Formula: see text] is characterized by a complex temporal double peak structure and strong spatial amplitude variation. An imprint of discrete pulses remains detectable during the entire propagation of the combined wave. An excellent agreement between the results produced with different numerical codes is obtained. Nonlinear effects associated with equation of state are found to be significant at impact velocities of [Formula: see text], while at lower velocities of [Formula: see text] the difference between the results obtained with linear and nonlinear equations of state is negligible. Liquid–gas interface dynamics during the compression process of a spherical gas cavity is captured very well by the compressibleInterFoam within OpenFOAM.

Double-peak structure of the nonresonant photoresponse of terahertz quantum Hall detectors

2008 ◽  
Vol 78 (17) ◽  
Author(s):  
G. Nachtwei ◽  
F. Gouider ◽  
C. Stellmach ◽  
G. Vasile ◽  
Yu. B. Vasilyev ◽  
...  
Keyword(s):  
Quantum Hall ◽  
Double Peak ◽  
Double Peak Structure ◽  
Peak Structure
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