相关论文: Non-Linear Convergence of Solar-like Stars Chromos…

Recent three-dimensional radiation hydrodynamic simulations by Wedemeyer et al. (2004) suggest that the solar chromosphere is highly structured in space and time on scales of only 1000 km and 20-25 sec, resp.. The resulting pattern consists…

We describe a self-consistent spectrum analysis technique employing non-LTE line formation, which allows precise atmospheric parameters of massive stars to be derived: 1sigma-uncertainties as low as ~1% in effective temperature and…

We aim to constrain the geometrical extent of the chromosphere of non-binary K giant stars and detect any spatial structures in the chromosphere. We performed observations with the CHARA interferometer and the VEGA beam combiner at optical…

We report on two distinct computational approaches to self-consistently measure photospheric properties of large samples of stars. Both procedures consist of a set of several semi-integrated tasks based on shell and Python scripts, which…

The Atacama Large Millimeter/submillimeter Array (ALMA) offers new diagnostic possibilities that complement other commonly used diagnostics for the study of our Sun. In particular, ALMA's ability to serve as an essentially linear…

Although solar-analog stars have been studied extensively over the past few decades, most of these studies have focused on visible wavelengths, especially those identifying solar-analog stars to be used as calibration tools for…

Direct imaging of extra-solar planets is now a reality, especially with the deployment and commissioning of the first generation of specialized ground-based instruments such as the Gemini Planet Imager and SPHERE. These systems will allow…

We use state-of-the-art radiation-MHD simulations and 3D non-LTE radiative transfer computations to investigate \Halpha\ line formation in the solar chromosphere and apply the results of this investigation to develop the potential of…

Context. The solar chromosphere and the lower transition region is believed to play a crucial role in the heating of the solar corona. Models that describe the chromosphere (and the lower transition region), accounting for its highly…

The observational study of stars in the sub-millimetre regime has only rather recently begun and was made possible mainly by the Atacama Large Millimeter/submillimeter Array (ALMA). The emission mechanisms of this radiation from normal MS…

Aims. We aim at deriving stellar atmospheric parameters based on the photometric data from the Javalambre Photometric Local Universe Survey (J-PLUS) in addition to near-infrared photometry from the Two Micron All-Sky Survey (2MASS).…

ALMA will open a new chapter in the study of the Sun by providing a leap in spatial resolution and sensitivity compared to currently available mm wave- length observations. In preparation of ALMA, we have carried out a large number of…

Spatially resolved observations of the Sun and the astronomical sample size of stellar bodies are the respective key strengths of solar and stellar observations. However, the large difference in object brightness between the Sun and other…

The photospheric radius is one of the fundamental parameters governing the radiative equilibrium of a star. We report new observations of the nearest solar-type stars Alpha Centauri A (G2V) and B (K1V) with the VLTI/PIONIER optical…

Aims. We use advanced 3D NLTE radiative magnetohydrodynamic simulations of the solar atmosphere to carry out detailed tests of chromospheric diagnostics at millimeter and submillimeter wavelengths. Methods. We focused on the diagnostics of…

Obtaining measurements of chromospheric and photometric activity of stars with near-solar fundamental parameters and rotation periods is important for a better understanding of solar-stellar connection. We select a sample of 2603 stars with…

As part of our program to study stellar photospheric and chromospheric activity, we have examined several young solar type stars with activity levels intermediate between the Sun and the very active RS CVn binaries. We have analysed…

The Kepler space telescope yielded unprecedented data for the study of solar-like oscillations in other stars. The large samples of multi-year observations posed an enormous data analysis challenge that has only recently been surmounted.…

The Atacama Large Millimeter/submillimeter Array (ALMA) allows for solar observations in the wavelength range of 0.3$-$10 mm, giving us a new view of the chromosphere. The measured brightness temperature at various frequencies can be fitted…

The Atacama Large Millimeter/submillimeter Array offers an unprecedented view of our Sun at sub-/millimeter wavelengths. The high spatial, temporal, and spectral resolution facilitates the measurement of gas temperatures and magnetic fields…