Related papers: Stellar granulation as seen in disk-integrated int…
The Sun provides us with the only spatially well-resolved astrophysical example of turbulent thermal convection. While various aspects of solar photospheric turbulence, such as granulation (one-Megameter horizontal scale), are well…
Transits of exoplanets across cool stars contain blended information about structures on the stellar surface and about the planetary body and atmosphere. To advance understanding of how this information is entangled, a surface-flux…
A forward model is described in which we synthesize spectra from an ab-initio 3D MHD simulation of an outer stellar atmosphere, where the coronal heating is based on braiding of magnetic flux due to photospheric footpoint motions. We…
We review the state of the art of three dimensional numerical simulations of solar and stellar dynamos. We summarize fundamental constraints of numerical modelling and the techniques to alleviate these restrictions. Brief summary of the…
For many years, there seemed to be significant differences between the continuum intensity distributions derived from observations and simulations of the solar photosphere. In order to settle the discussion on these apparent discrepancies,…
In an effort to estimate the largely unknown effects of photospheric temperature fluctuations on spectroscopic abundance determinations, we have studied the problem of LTE line formation in the inhomogeneous solar photosphere based on…
The goal of this research is to investigate how magnetic field affects the dynamics of granular convection and excitation of solar oscillations by means of realistic numerical simulations. We have used a 3D, compressible, non-linear…
This paper investigates the conditions for producing rapid variations of solar ener- getic particle (SEP) intensity commonly known as dropouts. In particular, we use numerical model simulations based on solving the focused transport…
The detectability of exoplanets and the determination of their projected mass in radial velocity are affected by stellar magnetic activity and photospheric dynamics. The effect of granulation, and even more so of supergranulation, has been…
Young massive stars in the central parsec of our Galaxy are best explained by star formation within at least one, and possibly two, massive self-gravitating gaseous discs. With help of numerical simulations, we here consider whether the…
Balmer lines serve as important indicators of stellar effective temperatures in late-type stellar spectra. One of their modelling uncertainties is the influence of convective flows on their shape. We aim to characterize the influence of…
Main sequence, solar-like stars (M < 1.5 Msun) have outer convective envelopes that are sufficiently thick to affect significantly their overall structure. The radii of these stars, in particular, are sensitive to the details of…
The Galactic disk is expected to be spatially, kinematically, and chemically clustered on many scales due to both star formation and non-axisymmetries in the Galactic potential. In this work we calculate the spatial and kinematic two-point…
Solar flares are 3D phenomenon but modelling a flare in 3D, including many of the important processes in the chromosphere, is a computational challenge. Accurately modelling the chromosphere is important, even if the transition region and…
Recent photometric observations of massive stars have identified a low-frequency power excess which appears as stochastic low-frequency variability in light curve observations. We present the oscillation properties of high resolution…
We present evolutionary models for solar-like stars with an improved treatment of convection that results in a more accurate estimate of the radius and effective temperature. This is achieved by improving the calibration of the…
A new class of models of stellar discs is introduced and used to build a self-consistent model of our Galaxy. The model is defined by the parameters that specify the action-based distribution functions (DFs) f(J) of four stellar discs…
Context. Local correlation tracking of granulation (LCT) is an important method for measuring horizontal flows in the photosphere. This method exhibits a systematic error that looks like a flow converging towards disk center, also known as…
The mechanism and characteristics of the irregular variations of red supergiants (RSGs) are studied based on the RSG samples in Small Magellanic Cloud (SMC), Large Magellanic Cloud (LMC) and M31. With the time-series data from All-Sky…
Stars on the lower main sequence (F-type through M-type) have substantial convective envelopes beneath their stellar photospheres. Convection in these regions can couple with rotation to build global-scale structures that may be observable…