Related papers: Solar and stellar activity cycles -- no synchroniz…
Recent spectro-polarimetric observations of solar-type stars have shown the presence of photospheric magnetic fields with a predominant toroidal component. If the external field is assumed to be current-free it is impossible to explain…
Virial theorem is important for understanding stellar structures. It produces an interesting connection between the magnetic energy and the gravitational one. Using the general form of the virial theorem including the magnetic field…
The magnetic field of the Sun is generated by internal dynamo process with a cyclic period of 11 years or a 22 year magnetic cycle. The signatures of the Sun's magnetic cycle are observed in the different layers of its atmosphere and in its…
The Sun is a magnetically active star and is the source of the solar wind, electromagnetic radiation and energetic particles which affect the heliosphere and the Earths atmosphere. The magnetic field of the Sun is responsible for most of…
Understanding the irregular variation of the solar cycle is crucial due to its significant impact on global climates and the heliosphere. Since the polar magnetic field determines the amplitude of the next solar cycle, variations in the…
Two fundamental properties of stellar magnetic fields have been determined by observations for solar-like stars with different Rossby numbers (Ro), namely, the magnetic field strength and the magnetic cycle period. The field strength…
Today, the generation of magnetic fields in solar-type stars and its relation to activity and rotation can coherently be explained, although it is certainly not understood in its entirety. Rotation facilitates the generation of magnetic…
Late-type stars interact with their close-in planets through their coronal magnetic fields. We introduce a theory for the interaction between the stellar and planetary fields focussing on the processes that release magnetic energy in the…
Having advanced knowledge of solar activity is important because the Sun's magnetic output governs space weather and impacts technologies reliant on space. However, the irregular nature of the solar cycle makes solar activity predictions a…
Both stars and planets can lose mass through an expansive wind outflow, often constrained or channeled by magnetic fields that form a surrounding magnetosphere. The very strong winds of massive stars are understood to be driven by…
Magnetic fields can be created in stably stratified (non-convective) layers in a differentially rotating star. A magnetic instability in the toroidal field (wound up by differential rotation) replaces the role of convection in closing the…
Zeeman Doppler imaging has successfully mapped the large-scale magnetic fields of stars over a large range of spectral types, rotation periods and ages. When observed over multiple epochs, some stars show polarity reversals in their global…
The diagram of indices of coronal and chromospheric activity allowed us to reveal stars where solar-type activity appears and regular cycles are forming. Using new consideration of a relation between coronal activity and the rotation rate,…
The planets magnetic field has been explained based on the dynamo theory, which presents as many difficulties in mathematical terms as well as in predictions. It proves to be extremely difficult to calculate the dipolar magnetic moment of…
The magnetic fields of solar-type stars are observed to cycle over decadal periods -11 years in the case of the Sun. The fields originate in the turbulent convective layers of stars and have a complex dependency upon stellar rotation rate.…
Initially, we present our original fast dynamo mechanism being potentially at work concerning the Sun and the solar type stars. Then, based on this new prototype model, a dynamo action model explaining the generation of the magnetic fields…
Stellar activity is fundamental to stellar evolution and the formation and habitability of exoplanets. The interaction between convective motions and rotation in cool stars results in a dynamo process that drives magnetic surface activity.…
It is a long-standing question in exoplanet research if Hot Jupiters can influence the magnetic activity of their host stars. While cool stars usually spin down with age and become inactive, an input of angular momentum through tidal…
The architecture of exoplanetary systems is often different from the solar system, with some exoplanets being in close orbits around their host stars and having orbital periods of only a few days. In analogy to interactions between stars in…
The magnetic activity of planet-hosting stars is an important factor to estimate the atmospheric stability of close-in exoplanets and the age of their host stars. It has long been speculated that close-in exoplanets can influence the…