221 datasets found

Coronal holes are usually defined as dark structures seen in the extreme ultraviolet and X-ray spectrum which are generally associated with open magnetic fields. Deriving...

This paper combines the precise determination of the energy levels of ^4^HeI from calculations and experiments with theoretical transition probabilities to present multiplet...

This paper presents semiempirical models of various solar magnetic structures, extending from the photosphere to the chromosphere. The models have been derived from non-LTE...

We have conducted spectrum analyses of 24 field metal-poor ([Fe/H]<-2) red horizontal-branch (RHB) stars identified in the HK objective-prism survey and 6 such stars in the...

Growing evidence has indicated that the global composition distribution plays an indisputable role in interpreting observational data. Three-dimensional general circulation...

Limb darkening is an important stellar phenomenon, and must be accounted for in the study of stellar spectra, eclipsing binaries, transiting planetary systems, and microlensing...

The characterisation of the atmosphere of exoplanets is one of the main goals of exoplanet science in the coming decades. We investigate the detectability of atmospheric...

The atmospheres of cool stars are temporally and spatially inhomogeneous due to the effects of convection. The influence of this inhomogeneity, referred to as granulation, on...

Grids of H{beta} indices based on updated (new-ODF) ATLAS9 model atmospheres were computed for solar and scaled solar metallicities [+0.5], [+0.2], [0.0], [-0.5], [-1.0],...

In the past few years, the number of space missions with astrophysical purposes has increased, with COROT, KEPLER, MOST and more recently TESS. Two of the most important...

A grid of ATLAS9 model atmospheres has been computed, spanning Teff in 3500--8000K, log.g in 0.0--5.0, [Fe/H] in -4.0--0.0, [{alpha}/Fe] in -0.08--1.2. These parameters are...

Libraries of stellar spectra are fundamental tools for the study of stellar populations and both empirical and synthetic libraries have been used for this purpose. In this...

Using new sets of stellar evolution models at very low metallicities (Z=10^-7^; 10^-5^) and previously published grids we examine spectral properties of the ionising continua,...

In order to study how the conventional spectroscopic method based on the equivalent widths of the Fe I and Fe II lines effectively applies to determining the atmospheric...

An extensive profile-fitting analysis was performed for the Li(+Fe) 6707-6708{AA} feature of nearby 160 F-K dwarfs/subgiants (including 27 planet-host stars) in the Galactic...

Based on a collection of high-dispersion spectra obtained at Okayama Astrophysical Observatory, the atmospheric parameters (Teff, logg, vt, and [Fe/H]) of 160 mid-F through...

The goal of this Research Note is to provide the theoretical calculations of the limb-darkening coefficients (LDC) and gravity-darkening coefficients (GDC) for the space mission...

A number of spectroscopic surveys have been carried out or are planned to study the origin of the Milky Way. Their exploitation requires reliable automated methods and softwares...

We reconsidered the previous studies of properties of magnetic stars based on the latest data on average surface magnetic fields of 177 stars. New, corrected results have been...

The paper presents the results of determination of fundamental parameters (effective temperature, surface gravity, luminosity, mass, radius, rotation velocity, and radial...