scholarly journals Iron abundance determination for the solar-like stars HR 4345 and HR 6573

2004 ◽  
pp. 41-45 ◽  
Author(s):  
Oliver Vince ◽  
Istvan Vince
Keyword(s):  
Software Package ◽  
Input Data ◽  
Spectral Lines ◽  
Software Packages ◽  
Iron Abundance ◽  
Microturbulent Velocity ◽  
Abundance Determination

Using the BLACKWELL software package written by R.O. Gray, the iron abundance of the solar-like stars HR 4345 and HR 6573 has been determined. The method is based on determination of the minimum dispersion (or the region of least confusion) of the iron abundance versus microturbulent velocity functions for some selected spectral lines of neutral iron. The input data used by BLACKWELL are the observed equivalent widths of several spectral lines of neutral iron. They are obtained from spectra observed at the Observatoire de Haute-Provence, France, with the 1.52-m telescope and Aurelie spectrograph. Reduction of the raw spectra and the measurement of the equivalent widths of spectral lines are carried out using IRAF and SPE software packages. The measured values of iron abundances of HR 4345 and HR 6573 are 7.72?0.03 and 7.63?0.05 respectively.

scholarly journals Determination of metallicity of the HR7914 solar-like star

2003 ◽  
pp. 69-74 ◽  
Author(s):  
Oliver Vince ◽  
Istvan Vince
Keyword(s):  
Spectral Line ◽  
Stellar Atmosphere ◽  
Astronomical Observatory ◽  
Program Package ◽  
Spectral Lines ◽  
Iron Abundance ◽  
Microturbulent Velocity

By using the Blackwell program package by R.O. Gray, the metallicity of the HR7914 solar-like star was determined. The program package utilizes measured equivalent widths of several chosen neutral iron spectral lines from the observed spectra, appropriate atomic and spectral line parameters and adequate Kurucz?s stellar atmosphere models. The method is based on determination of the minimum dispersion of the iron abundance versus microturbulent velocity functions for the selected neutral iron spectral lines. The spectra were observed at National Astronomical Observatory Rozhen (NAO Rozhen), Bulgaria, using the 2m-telescope and Coude spectrograph. They were reduced with the IRAF program package. The measurement of the spectral line parameters was done with the SPE program package. The metallicity of the HR7914 solar-like star was determined to be 0.02.

scholarly journals Inferring telescope polarization properties through spectral lines without linear polarization

2018 ◽  
Vol 615 ◽  
pp. A22 ◽  
Author(s):  
A. Derks ◽  
C. Beck ◽  
V. Martínez Pillet
Keyword(s):  
Linear Polarization ◽  
Input Data ◽  
Polarization State ◽  
Active Regions ◽  
Spectral Lines ◽  
Solar Telescope ◽  
Promising Tool ◽  
Visible Part ◽  
Telescope Optics

Context. Polarimetric observations taken with ground- or space-based telescopes usually need to be corrected for changes of the polarization state in the optical path. Aims. We present a technique to determine the polarization properties of a telescope through observations of spectral lines that have no or negligible intrinsic linear polarization signals. For such spectral lines, any observed linear polarization must be induced by the telescope optics. We apply the technique to observations taken with the Spectropolarimeter for Infrared and Optical Regions (SPINOR) at the Dunn Solar Telescope (DST) and demonstrate that we can retrieve the characteristic polarization properties of the DST at three wavelengths of 459, 526, and 615 nm. Methods. We determine the amount of crosstalk between the intensity Stokes I and the linear and circular polarization states Stokes Q, U, and V, and between Stokes V and Stokes Q and U in spectropolarimetric observations of active regions. We fit a set of parameters that describe the polarization properties of the DST to the observed crosstalk values. We compare our results to parameters that were derived using a conventional telescope calibration unit (TCU). Results. The values for the ratio of reflectivities X = rs∕rp and the retardance τ of the DST turret mirrors from the analysis of the crosstalk match those derived with the TCU within the error bars. We find a negligible contribution of retardance from the entrance and exit windows of the evacuated part of the DST. Residual crosstalk after applying a correction for the telescope polarization stays at a level of 3–10% regardless of which parameter set is used, but with an rms fluctuation in the input data of already a few percent. The accuracy in the determination of the telescope properties is thus more limited by the quality of the input data than the method itself. Conclusions. It is possible to derive the parameters that describe the polarization properties of a telescope from observations of spectral lines without intrinsic linear polarization signal. Such spectral lines have a dense coverage (about 50 nm separation) in the visible part of the spectrum (400–615 nm), but none were found at longer wavelengths. Using spectral lines without intrinsic linear polarization is a promising tool for the polarimetric calibration of current or future solar telescopes such as the Daniel K. Inouye Solar Telescope (DKIST).

scholarly journals The Solar Photospheric Nitrogen Abundance: Determination with 3D and 1D Model Atmospheres

2009 ◽  
Vol 26 (3) ◽  
pp. 345-350 ◽  
Author(s):  
E. Maiorca ◽  
E. Caffau ◽  
P. Bonifacio ◽  
M. Busso ◽  
R. Faraggiana ◽  
...  
Keyword(s):  
Local Thermodynamic Equilibrium ◽  
Spectral Lines ◽  
Solar Photosphere ◽  
Radiation Hydrodynamics ◽  
1D Model ◽  
Nitrogen Abundance ◽  
Width Measurements ◽  
Hydrodynamical Modelling ◽  
Abundance Determination

AbstractWe present a new determination of the solar nitrogen abundance making use of 3D hydrodynamical modelling of the solar photosphere, which is more physically motivated than traditional static 1D models. We selected suitable atomic spectral lines, relying on equivalent width measurements already existing in the literature. For atmospheric modelling we used the co5bold 3D radiation hydrodynamics code. We investigated the influence of both deviations from local thermodynamic equilibrium (non-LTE effects) and photospheric inhomogeneities (granulation effects) on the resulting abundance. We also compared several atlases of solar flux and centre-disc intensity presently available. As a result of our analysis, the photospheric solar nitrogen abundance is A(N) = 7.86 ± 0.12.

scholarly journals An Analysis of Microturbulence in the Atmosphere of the F-Type Supergiant Gamma CYGNI

1980 ◽  
Vol 51 ◽  
pp. 292-293
Author(s):  
A.A. Boyarchuk ◽  
L.S. Lyubimkov
Keyword(s):  
Detailed Analysis ◽  
Optical Depth ◽  
Spectral Lines ◽  
High Dispersion ◽  
Depth Dependence ◽  
Systematic Discrepancy ◽  
Iron Abundance ◽  
Growth Method ◽  
Microturbulent Velocity

AbstractWe have analysed high dispersion spectra of the supergiant γ Cyg (F8 Ib). On the basis of the curve of growth method it has been shown that there is no dependence of microturbulent velocity ξt on excitation potentials of spectral lines. Using model atmospheres we considered about 100 Fe I lines and found that no constant value ξt makes possible to remove the systematic discrepancy in iron abundance between groups of lines with different equivalent widths. The depth dependence of microturbulence in the atmosphere is investigated. It is shown that parameter ξt increases outwards from about 0-1 km/s at the optical depth τ5000 = 0.2 to 10 km/s at the depth τ5000 = 10-3. Deducted function ξt (τ5000) gives the same iron abundance log ε(Fe) = T = 7.45 ± 0.05 for all groups of Fe I lines. The detailed analysis will be published in Izv. Crimean Astrophys. Obs.

Unlocking the potential of eddy covariance data with the R software package openeddy

2020 ◽  
Author(s):  
Ladislav Šigut ◽  
Pavel Sedlák ◽  
Milan Fischer ◽  
Georg Jocher ◽  
Thomas Wutzler ◽  
...  
Keyword(s):  
Quality Control ◽  
Eddy Covariance ◽  
Data Aggregation ◽  
Software Package ◽  
Input Data ◽  
Ease Of Use ◽  
Post Processing ◽  
R Software ◽  
Software Packages ◽  
Processing Steps

<p><span lang="EN-US">The eddy covariance method provides important insights about CO<sub>2</sub>, water and energy exchange-related processes on the ecosystem scale level. Data are collected quasi-continuously with sampling frequency 10 Hz at minimum, often throughout multiple years, producing large datasets. Standard data processing methods are already devised but undergo continuous refinements that should be reflected in the available software. Currently, a suite of software packages is available for computation of half-hourly products from high frequency raw data. However, software packages consolidating the further post-processing computations are not yet that common. The post-processing steps can consist of quality control, footprint modelling, computation of storage fluxes, gap-filling, flux partitioning and data aggregation. Also they can be realized in different programming languages and require various input data formats. Users would therefore often evaluate only certain aspects of the dataset which limits the amount of extractable information from obtained data and they possibly omit the features that could affect data quality or interpretation. Here we present the free R software package openeddy (<a href="https://github.com/lsigut/openeddy">https://github.com/lsigut/openeddy</a>) that provides utilities for input data handling, extended quality control checks, data aggregation and visualization and that includes a workflow (<a href="https://github.com/lsigut/EC_workflow">https://github.com/lsigut/EC_workflow</a>) that attempts to integrate all post-processing steps through incorporation of other free software packages, such as REddyProc (<a href="https://github.com/bgctw/REddyProc/">https://github.com/bgctw/REddyProc/</a>). The framework is designed for the standard set of eddy covariance fluxes, i.e. of momentum, latent and sensible heat as well as CO<sub>2</sub>. Special attention was paid to the visualization of results at different stages of processing and at different time resolutions and aggregation steps. This allows to quickly check that computations were performed as expected and it also helps to notice issues in the dataset itself. Finally, the proposed folder structure with defined post-processing steps allows to organize data in different stages of processing for improved ease of use. Produced workflow files document the whole processing chain and its possible adaptations for a given site. We believe that such a tool can be particularly useful for eddy-covariance novices, groups that cannot or do not contribute their data to regional networks for further processing or users that want to evaluate their data independently. This or similar efforts can also help to save human resources or speed up the development of new methods.</span></p> <p><span lang="EN-US">This work was supported by the Ministry of Education, Youth and Sports of the Czech Republic within the CzeCOS program, grant number LM2015061, and within Mobility CzechGlobe 2, grant number CZ.02.2.69/0.0/0.0/18_053/0016924.</span></p>

scholarly journals The Semiclassical Limit of the Gailitis Formula Applied to Electron Impact Broadening of Spectral Lines of Ionized Atoms

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 29
Author(s):  
Sylvie Sahal-Bréchot
Keyword(s):  
Electron Impact ◽  
Classical Limit ◽  
Semiclassical Limit ◽  
Spectral Lines ◽  
Stark Broadening ◽  
Feshbach Resonances

The present paper revisits the determination of the semi-classical limit of the Feshbach resonances which play a role in electron impact broadening (the so-called “Stark“ broadening) of isolated spectral lines of ionized atoms. The Gailitis approximation will be used. A few examples of results will be provided, showing the importance of the role of the Feshbach resonances.

scholarly journals Determination of stress-strain state of the wooden church log walls with software package

2016 ◽  
Vol 86 ◽  
pp. 02019 ◽  
Author(s):  
Anastasia Chulkova ◽  
Sergey Lukichev ◽  
Marina Romanovich
Keyword(s):  
Software Package ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State

scholarly journals Integration, scaling, space-group assignment and post-refinement

2010 ◽  
Vol 66 (2) ◽  
pp. 133-144 ◽  
Author(s):  
Wolfgang Kabsch
Keyword(s):  
Data Reduction ◽  
Efficient Algorithm ◽  
Spot Size ◽  
Crystal Symmetry ◽  
Automatic Determination ◽  
Scaling Factors ◽  
Space Group ◽  
Group Assignment ◽  
Software Packages

Important steps in the processing of rotation data are described that are common to most software packages. These programs differ in the details and in the methods implemented to carry out the tasks. Here, the working principles underlying the data-reduction packageXDSare explained, including the new features of automatic determination of spot size and reflecting range, recognition and assignment of crystal symmetry and a highly efficient algorithm for the determination of correction/scaling factors.

Measurement and analysis of species distribution in laser-induced ablation plasma of an aluminum-magnesium alloy

2021 ◽  
Author(s):  
Junxiao Wang ◽  
Shuqing Wang ◽  
Lei Zhang ◽  
Maogen Su ◽  
Duixiong Sun ◽  
...  
Keyword(s):  
Species Distribution ◽  
Laser Energy ◽  
Integral Intensity ◽  
Spectral Lines ◽  
Imaging Method ◽  
Measurement And Analysis ◽  
Ablation Plasma ◽  
Spatio Temporal ◽  
Differential Imaging

Abstract We proposed a theoretical spatio-temporal imaging method, which was based on the thermal model of laser ablation and the two-dimensional axisymmetric multi-species hydrodynamics model. By using the intensity formula, the integral intensity of spectral lines could be calculated and the corresponding images of intensity distribution could be drawn. Through further image processing such as normalization, determination of minimum intensity, combination and color filtering, a relatively clear species distribution image in the plasma could be obtained. Using the above method, we simulated the plasma ablated from Al-Mg alloy by different laser energies under 1 atm argon, and obtained the theoretical spatio-temporal distributions of Mg I, Mg II, Al I, Al II and Ar I species, which are almost consistent with the experimental results by differential imaging. Compared with the experimental decay time constants, the consistency is higher at low laser energy, indicating that our theoretical model is more suitable for the plasma dominated by laser-supported combustion wave.

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