相关论文: Using Chandra/LETG spectra to probe stellar corona…
We present a three-dimensional simulation of the corona of an FK Com-type rapidly rotating G giant using a magnetohydrodynamic model that was originally developed for the solar corona in order to capture the more realistic, non-potential…
Data from recent numerical simulations of the solar corona and transition region are analysed and the magnetic field connection between the low corona and the photosphere is found to be close to that of a potential field. The fieldline to…
The magnetic fields of young stars set their coronal properties and control their spin evolution via the star-disc interaction and outflows. Using 14 magnetic maps of 10 classical T Tauri stars (CTTSs) we investigate their closed X-ray…
We present the analysis and interpretation of an observation of the flare star AD Leo (dM3e) with Chandra/LETG. The high resolution X-ray spectrum allowed us to infer the plasma emission measure distribution (EMD) vs. temperature, and the…
Stellar coronae, defined by the ensemble of magnetic field structures above stellar photospheres and chromospheres together with their thermal or non-thermal plasma content, play an important role in our understanding of stellar magnetic…
Information on the rotation rate of the corona, and its variation over latitude and solar cycle, is valuable for making global connections between the corona and the Sun, for global estimates of reconnection rates, and as a basic parameter…
The ultraviolet stellar wind lines of the photometrically periodic variable early B-type star sigma Lupi were found to behave very similarly to what has been observed in known magnetic B stars, although no periodicity could be determined.…
X-ray observations provide a key tool for exploring the properties of galactic coronae and their formation processes. In an earlier paper, we have presented a Chandra data analysis of the coronae of 53 nearby highly-inclined disc galaxies.…
We report on a detailed radiative transfer modeling of the observed scattering polarization in the H-alpha line, which allows us to infer quantitative information on the magnetization of the quiet solar chromosphere. Our analysis suggests…
The solar corona is host to a continuous flow of propagating disturbances (PD). These are continuous and ubiquitous across broad regions of the corona, including the quiet Sun. The aim of this paper is to present an improved, efficient…
We investigate the standing kink modes of a cylindrical model of coronal loops. The density is stratified along the loop axis and changes discontinuously at the surface of the cylinder. The periods and mode profiles are studies with their…
We present a systematical analysis of the Chandra observations of 53 nearby highly-inclined (i>60 degree) disk galaxies to study the coronae around them. This sample covers a broad range of galaxy properties: e.g., about three orders of…
A main source of bias in transmission spectroscopy of exoplanet atmospheres is magnetic activity of the host star in the form of stellar spots, faculae or flares. However, the fact that main-sequence stars have a chromosphere and a corona,…
With the rapid development of asteroseismology thanks to space-based photometry missions such as CoRoT, Kepler, TESS, and in the future, PLATO, and the use of inversion techniques, quasi-model-independent constraints on the stellar…
Angular broadening observations of compact radio sources provide a powerful method for probing the solar corona and solar wind. Such observations enable studies of the phase structure function, turbulence amplitude, intermediate-scale…
Our knowledge of magnetic activity of stars is mostly based on the study of the Sun and some spectroscopic surveys of a few hundreds of stars. However, the detailed mechanisms of the solar magnetic activity cycle are not fully understood.…
Frequency splitting coefficients from Global Oscillation Network Group (GONG) and Michelson Doppler Imager (MDI) observations covering the period 1995--2001 are used to study temporal variations in the solar rotation rate at high latitudes.…
We present the first short time scale observations of the roAp star gamma Equ in linear polarized light obtained with the PEPSI polarimeter installed at the LBT. These observations are used to search for pulsation variability in Stokes Q…
Solar flares are driven by release of free magnetic energy and often associated with restructurization of the magnetic field topology. Yet, observations of evolving magnetic field in the flaring volume are limited to very few cases…
The solar corona is orders of magnitude hotter than the underlying photosphere, but how the corona attains such high temperatures is still not understood. Soft X-ray (SXR) emission provides important diagnostics for thermal processes in the…