相关论文: A solar spectroscopic absolute abundance of argon …
Solar X-ray spectra from the RESIK crystal spectrometer on the {\em CORONAS-F} spacecraft (spectral range $3.3-6.1$~\AA) are analyzed for thirty-three flares using a method to derive abundances of Si, S, Ar, and K, emission lines of which…
The RESIK instrument on {\em CORONAS-F} spacecraft observed several sulphur X-ray lines in three of its four channels covering the wavelength range 3.8-6.1 \AA\ during solar flares. The fluxes are analyzed to give the sulphur abundance.…
The solar X-ray continuum emission at five wavelengths between 3.495 Angstroms and 4.220 Angstroms for 19 flares in a seven-month period in 2002--2003 was observed by the RESIK crystal spectrometer on CORONAS-F. In this wavelength region,…
The abundance of chlorine is determined from X-ray spectra obtained with the RESIK instrument on {\em CORONAS-F} during solar flares between 2002 and 2003. Using weak lines of He-like Cl, \ion{Cl}{16}, between 4.44 and 4.50 \AA, and with…
The RESIK instrument on the CORONAS-F spacecraft obtained solar flare and active region X-ray spectra in four channels covering the wavelength range 3.8 -- 6.1 \AA in its operational period between 2001 and 2003. Several highly ionized…
The Ar XVII X-ray line group principally due to transitions 1s2 - 1s2l (l=s, p) near 4 Anstroms was observed in numerous flares by the RESIK bent crystal spectrometer aboard CORONAS-F between 2001 and 2003. The three line features include…
Previous estimates of the solar flare abundances of Si, S, Cl, Ar, and K from the RESIK X-ray crystal spectrometer on board the CORONAS-F spacecraft were made on the assumption of isothermal X-ray emission. We investigate the effect on…
The solar argon abundance cannot be directly derived by spectroscopic observations of the solar photosphere. The solar Ar abundance is evaluated from solar wind measurements, nucleosynthetic arguments, observations of B stars, HII regions,…
The abundance of iron is measured from emission line complexes at 6.65 keV (Fe line) and 8 keV (Fe/Ni line) in {\em RHESSI} X-ray spectra during solar flares. Spectra during long-duration flares with steady declines were selected, with an…
The abundance of potassium is derived from X-ray lines observed during flares by the RESIK instrument on the solar mission CORONAS-F between 3.53 A and 3.57 A. The lines include those emitted by He-like K and Li-like K dielectronic…
The ratio of the Fe abundance in the photosphere to that in coronal flare plasmas is determined by X-ray lines within the complex at 6.7~keV (1.9~\AA) emitted during flares. The line complex includes the He-like Fe (\fexxv) resonance line…
We observed the coronally active eclipsing binary, AR Lac, with the High Energy Transmission Grating on Chandra for a total of 97 ks, spaced over five orbits, at quadratures and conjunctions. Contemporaneous and simultaneous EUV spectra and…
We present a measurement of the abundance of Fe relative to H in the solar corona using a technique which differs from previous spectroscopic and solar wind measurements. Our method combines EUV line data from the CDS spectrometer on SOHO…
Argon abundances have been derived for a sample of B main-sequence stars in the Orion association. The abundance calculations are based on NLTE metal line-blanketed model atmospheres calculated with the NLTE code TLUSTY and an updated and…
The quiet-Sun X-ray emission is important for deducing coronal heating mechanisms, but it has not been studied in detail since the Orbiting Solar Observatory (OSO) spacecraft era. Bragg crystal spectrometer X-ray observations have generally…
At altitudes of about 1.05 solar radii or more, the corona above quiet solar regions becomes essentially isothermal. This obviates many of the difficulties associated with the inverse problem of determining emission measure distributions,…
Chandra HETG spectra of the coronally active binary stars sigma Gem and HR 1099 are among the highest fluence observations for such systems taken at high spectral resolution in x-rays with this instrument. We compare their properties to…
Analysis of RHESSI 3--10 keV spectra for 27 solar flares is reported. This energy range includes thermal free--free and free--bound continuum and two line features, at 6.7keV and 8keV, principally due to highly ionized iron (Fe). We used…
{The \ion{Na}{x} X-ray lines between 10.9 and 11.2~\AA\ have attracted little attention but are of interest since they enable an estimate of the coronal abundance of Na to be made. This is of great interest in the continuing debate on the…
Monte Carlo calculations of the Ne K$\alpha$ line fluoresced by coronal x-rays and emitted near the temperature minimum region of the solar atmosphere have been employed to investigate the use of this feature to measure directly the solar…