A non-local thermodynamic equilibrium radiative transfer model for infrared emissions in the atmosphere of Mars: 2. Daytime populations of vibrational levels

1994 ◽  
Vol 99 (E6) ◽  
pp. 13117 ◽  
Author(s):  
M. A. Lopèz-Valverde ◽  
M. Lopèz-Puertas
Keyword(s):  
Radiative Transfer ◽  
Thermodynamic Equilibrium ◽  
Local Thermodynamic Equilibrium ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Vibrational Levels ◽  
Non Local ◽  
Infrared Emissions

scholarly journals kCARTA: a fast pseudo line-by-line radiative transfer algorithm with analytic Jacobians, fluxes, nonlocal thermodynamic equilibrium, and scattering for the infrared

2020 ◽  
Vol 13 (1) ◽  
pp. 323-339 ◽  
Author(s):  
Sergio DeSouza-Machado ◽  
L. Larrabee Strow ◽  
Howard Motteler ◽  
Scott Hannon
Keyword(s):  
Radiative Transfer ◽  
Thermodynamic Equilibrium ◽  
Local Thermodynamic Equilibrium ◽  
Singular Value ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Clear Sky ◽  
Non Local ◽  
Value Decomposition ◽  
Current Database

Abstract. A fast pseudo-monochromatic radiative transfer package using a singular value decomposition (SVD) compressed atmospheric optical depth database has been developed, primarily for simulating radiances from hyperspectral sounding instruments (resolution ≥0.1 cm−1). The package has been tested extensively for clear-sky radiative transfer cases, using field campaign data and satellite instrument data. The current database uses HITRAN 2016 line parameters and is primed for use in the spectral region spanning 605 to 2830 cm−1. Optical depths for other spectral regions (15–605 and 2830–45 000 cm−1) can also be generated for use by kCARTA. The clear-sky radiative transfer model computes the background thermal radiation quickly and accurately using a layer-varying diffusivity angle at each spectral point; it takes less than 30 s (on a 2.8 GHz core using four threads) to complete a radiance calculation spanning the infrared. The code can also compute non-local thermodynamic equilibrium effects for the 4 µm CO2 region, as well as analytic temperature, gas and surface Jacobians. The package also includes flux and heating rate calculations and an interface to an infrared scattering model.

First NIR interferometrically resolved high-order Brackett and forbidden Fe lines of a B[e] star: V921 Sco

2019 ◽  
Vol 492 (1) ◽  
pp. 566-571
Author(s):  
Alexander Kreplin ◽  
Stefan Kraus ◽  
Larisa Tambovtseva ◽  
Vladimir Grinin ◽  
Edward Hone
Keyword(s):  
Radiative Transfer ◽  
Thermodynamic Equilibrium ◽  
Spectral Resolution ◽  
Near Infrared ◽  
Local Thermodynamic Equilibrium ◽  
Line Emission ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Shock Excitation ◽  
First Time

ABSTRACT We present near-infrared interferometric AMBER observations of the B[e] binary V921 Sco at low (R ∼ 30) and medium spectral resolution (R∼ 1500) in the K and H bands. Low spectral resolution AMBER data were used to estimate the position of the companion V921 Sco B and confirmed a clockwise movement on sky with respect to the primary of 33° between 2008 and 2012. Our observations resolve for the first time higher order Brackett lines (Br6–Br12). The modelling of the different line transitions revealed a decrease in the size of the line-emitting regions from Br3 to Br12. We are able to reproduce this decrease with a simple radiative transfer model of an equatorial disc in local thermodynamic equilibrium. In addition to the Brackett series, we also resolve permitted and forbidden Fe line emission. Our modelling shows that these lines originate from ∼2 au from the star, corresponding roughly to the measured dust sublimation region. This might indicate that the forbidden line emission arises from shock excitation at the base of a disc wind.

scholarly journals kCARTA: A fast pseudo line-by-line radiative transfer algorithmwith analytic Jacobians, fluxes, Non-Local ThermodynamicEquilibrium and scattering for the infrared

2019 ◽  
Author(s):  
Sergio DeSouza-Machado ◽  
L. Larrabee Strow ◽  
Howard Motteler ◽  
Scott Hannon
Keyword(s):  
Radiative Transfer ◽  
Singular Value Decomposition ◽  
Local Thermodynamic Equilibrium ◽  
Singular Value ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Clear Sky ◽  
Non Local ◽  
Value Decomposition ◽  
Current Database

Abstract. A fast pseudo-monochromatic radiative transfer package using a Singular Value Decomposition (SVD) compressed atmospheric optical depth database has been developed, primarily for use with hyperspectral sounding instruments. The package has been tested extensively for clear sky radiative transfer cases, using field campaign data and satellite instrument data. The current database uses HITRAN 2016 line parameters and is primed for use in the spectral region spanning 605 cm−1 to 2830 cm−1 (with a point spacing of 0.0025 cm−1), but can easily be extended to other regions. The clear sky radiative transfer model computes the background thermal radiation quickly and accurately using a layer-varying diffusivity angle at each spectral point; it takes less than 20 seconds (on a 2.8 GHz core using 4 threads) to complete a radiance calculation spanning the infrared. The code can also compute Non Local Thermodynamic Equilibrium effects for the 4 μm CO2 region, as well as analytic temperature, gas and surface jacobians. The package also includes flux and heating rate calculations, and an interface to a scattering model.

scholarly journals H and He in stripped-envelope SNe – how much can be hidden?

2011 ◽  
Vol 7 (S279) ◽  
pp. 122-125
Author(s):  
S. Hachinger ◽  
P. A. Mazzali ◽  
S. Taubenberger ◽  
W. Hillebrandt ◽  
K. Nomoto ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Thermodynamic Equilibrium ◽  
Stellar Evolution ◽  
Local Thermodynamic Equilibrium ◽  
Explosion Energy ◽  
High Mass ◽  
Synthetic Spectra ◽  
Non Local ◽  
Moderate Mass

AbstractH and He features in photospheric spectra have rarely been used to constrain the structure of Type IIb/Ib/Ic supernovae (SNe IIb/Ib/Ic). The lines have to be modelled with a detailed non-local-thermodynamic-equilibrium (NLTE) treatment, including effects uncommon in stars. Once this is done, however, one obtains valuable hints on the characteristics of progenitors and explosions (composition, explosion energy, . . .). We have extended a radiative transfer code to compute synthetic spectra of SNe IIb, Ib and Ic. Here, we discuss our first larger set of models, focusing on the question: How much H/He can be hidden (i.e. remain undetected in photospheric spectra) in SNe Ib/Ic? For the SNe studied (relatively low Mej = 1. . .3 M⊙), we find a limit of MHe ≲ 0.1 M⊙ in SNe Ic (no unambiguous He lines). Stellar evolution models for single stars normally always yield higher masses. We suggest that low- or moderate-mass SNe Ic result from efficient envelope stripping in binaries. We propose similar studies on H/He in high-mass and extremely aspherical SNe, and observations covering the region of He I λ 20581.

scholarly journals New insights for mesospheric OH: multi-quantum vibrational relaxation as a driver for non-local thermodynamic equilibrium

2018 ◽  
Vol 36 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Konstantinos S. Kalogerakis ◽  
Daniel Matsiev ◽  
Philip C. Cosby ◽  
James A. Dodd ◽  
Stefano Falcinelli ◽  
...  
Keyword(s):  
Thermodynamic Equilibrium ◽  
Vibrational Relaxation ◽  
Local Thermodynamic Equilibrium ◽  
Vibrational Excitation ◽  
Kinetic Temperature ◽  
Population Distributions ◽  
Vibrational Levels ◽  
Non Local ◽  
Relationship Of ◽  
The Relationship

Abstract. The question of whether mesospheric OH(v) rotational population distributions are in equilibrium with the local kinetic temperature has been debated over several decades. Despite several indications for the existence of non-equilibrium effects, the general consensus has been that emissions originating from low rotational levels are thermalized. Sky spectra simultaneously observing several vibrational levels demonstrated reproducible trends in the extracted OH(v) rotational temperatures as a function of vibrational excitation. Laboratory experiments provided information on rotational energy transfer and direct evidence for fast multi-quantum OH(high-v) vibrational relaxation by O atoms. We examine the relationship of the new relaxation pathways with the behavior exhibited by OH(v) rotational population distributions. Rapid OH(high-v) + O multi-quantum vibrational relaxation connects high and low vibrational levels and enhances the hot tail of the OH(low-v) rotational distributions. The effective rotational temperatures of mesospheric OH(v) are found to deviate from local thermodynamic equilibrium for all observed vibrational levels. Dedicated to Tom G. Slanger in celebration of his 5 decades of research in aeronomy.

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