Abstract A comprehensive multi-wavelength campaign has been carried out to probe stellar activity and variability in the young Sun-like star ι-Horologii. We present results from long-term spectropolarimetric monitoring of system by using ultra-stable spectropolarimeter/velocimeter HARPS at ESO 3.6-m telescope. Additionally, we included high-precision photometry NASA Transiting Exoplanet Survey ...

The equilibrium configuration of very small magnetic fluxtubes in an inter-granular environment automatically produces kG magnetic field strengths. We argue that such process takes place in the Sun and complements the convective collapse (CC), which is traditionally invoked to explain the formation of kG magnetic concentrations in the solar photosphere. In particular, it can concentrate the ver...

The solar acoustic oscillations are likely stochastically excited by convective dynamics in the photosphere, though few direct observations of individual source events have been made and their detailed characteristics still unknown. Wave identification requires measurements that can reliably discriminate local wave signal from background motions resonant modal power. This is quite challenging a...

Hydrodynamic simulations of granular convection predict the existence of supersonic flows covering∼3-4% of the solar surface at any time, but these flows have not been detected unambigously as yet. Using data from the spectropolarimeter aboard the Hinode satellite, I present direct evidence of fast horizontal plasma motions in quiet Sun granules. Their visibility increases toward the limb due t...

We use a flux transport model to simulate the evolution of the Sun’s magnetic dipole moment, polar fields, and open flux under Maunder minimum conditions. Even when the rate of active region emergence is taken to be a factor of 30 smaller than in recent solar cycles, regular polarity oscillations of the axial dipole and polar fields can be maintained if the speed of the poleward surface flow is...

We present a 3D simulation of the dynamic emergence of a twisted magnetic flux tube from the top layer of the solar convection zone into the solar atmosphere and corona. It is found that after a brief initial stage of flux emergence during which the two polarities of the bipolar region become separated and the tubes intersecting the photosphere become vertical, significant rotational motion set...

We compute magnetic helicity and energy spectra of the solar active region NOAA 11158 during 11–15 February 2011 at 20 southern heliographic latitude using observational photospheric vector magnetograms. We adopt the isotropic representation of the Fourier-transformed two-point correlation tensor of the magnetic field. The sign of magnetic helicity turns out to be predominantly positive at all ...

The main objective of the SunFlare project is modelling and understanding the couplings between the sub-surface layers and visible layers of the Sun: the solar photosphere, chromosphere and corona. – The mass density is much larger in the subsurface layers than in the visible layers. The kinetic and magnetic energy densities are also correspondingly large. The motions that occur in these layers...

Three different maps of the quiet Sun, observed with the Advanced Stokes Polarimeter (ASP) and the Diffraction-Limited Stokes Polarimeter (DLSP), show evidence of strong (≃1700 G) and weak (<500 G) fields coexisting within the resolution element both at network and internetwork locations. The angular resolution of the observations is of 1(ASP) and 0.6 (DLSP), respectively. Even at the higher DL...

High-cadence multiwavelength optical observations were taken with the Dunn Solar Telescope at the National Solar Observatory, Sacramento Peak, accompanied by Advanced Stokes Polarimeter vector magnetograms. A total of 11 network bright points (NBPs) have been studied at different atmospheric heights using images taken in wave bands centered on Mg i b1 0.4 Å, H , and Ca ii K3. Wavelet analysis w...