Related papers: Magnetic coronae of active main-sequence stars
In this paper, we present a novel view on the morphology and the dynamical state of 10 prominent, nearby ($\leq$ 500 pc), and young ($\sim$30-300 Myr) open star clusters with Gaia DR2: $\alpha\,$Per, Blanco 1, IC 2602, IC 2391, Messier 39,…
The surface magnetic fields of pre-main-sequence stars and zero-age main-sequence stars are notably strong, resulting in the generation of numerous spots and the emission of bright chromospheric lines. Rotational variations in magnetic…
Because of the tremendous densities that exist in the cores of neutron stars, a significant fraction of the matter in the cores of such stars is likely to exist in the form of hyperons. Depending on spin frequency, the hyperon content…
We present a brief review of observational results contributing to modern ideas on the evolution of stellar activity. Basic laws, derived for both rotation-age and activity-rotation relationships, allow us to trace how the activity of…
Asteroseismic inferences of main-sequence solar-like oscillators often rely on best-fit models. However, these models cannot fully reproduce the observed mode frequencies, suggesting that the internal structure of the model does not fully…
Non-accreting neutron stars display diverse characteristics, leading us to classify them into several groups. This chapter is an observational driven review in which we survey the properties of the different classes of isolated neutron…
Most of the emission coming from the solar corona is confined into closed magnetic structures in the form of arcs (loops). Very little is known about the structure of stellar coronae. The magnetic topology, however, can be inferred by…
Helioseismology has allowed us to infer the rotation in the greater part of the solar interior with high precision and resolution. The results show interesting conflicts with earlier theoretical expectations, indicating that the the Sun is…
Solar flares and coronal mass ejections are the largest energy release phenomena in the current solar system. They cause drastic enhancements of electromagnetic waves of various wavelengths and sometimes eject coronal material into the…
The structure and dynamics of the outer solar atmosphere are reviewed with emphasis on the role played by the magnetic field. Contemporary observations that focus on high resolution imaging over a range of temperatures, as well as UV, EUV…
Solar magnetized "tornadoes", a phenomenon discovered in the solar atmosphere, appear as tornado-like structures in the corona but root in the photosphere. Like other solar phenomena, solar tornadoes are a feature of magnetized plasma and…
Within the quiet Sun corona imaged at 1 MK, much of the field of view consists of diffuse emission that appears to lack the spatial structuring that is so evident in coronal loops or bright points. We seek to determine if these diffuse…
We show that the presence of a steady $\ao$ dynamo in astrophysical rotators likely leads to an outflow of relative magnetic helicity and thus magnetic energy available for particle acceleration in a corona. The connection between energy…
The fine structures of solar radio bursts reveal complex dynamics in the corona, yet the observed characteristics of these sub-second bursts are additionally complicated by radio wave scattering in the turbulent solar corona. We examine the…
Stars do not simply pop up on the main sequence. Before the stars arrive on the zero-age main sequence, they form in the collapses of molecular clouds, gain matter through accretion processes, and compress their cores until hydrogen can…
In-situ measurements by several spacecraft have revealed that the solar wind is frequently perturbed by transient structures (magnetic folds, jets, waves, flux-ropes) that propagate rapidly away from the Sun over large distances. Parker…
The present paper discusses the main physical effects produced by stellar rotation on presupernovae, as well as observations which confirm these effects and their consequences for presupernova models. Rotation critically influences the mass…
Binary stars produce an array of dramatic astrophysical phenomena. They allow us to probe stellar structure, nuclear physics, and gravitational wave physics. They also produce the powerful supernovae that allow us to measure the scale of…
We consider here the structure of rotating compact objects endowed with a magnetic field in general relativity as models of pulsars. We discuss first the structure of rotating stars in the framework of Hartle taking different realistic…
Stellar metallicity is a critical factor to characterize the stellar coronae because it directly affects the radiative energy loss from the atmosphere. By extending theoretical relations for solar coronal loops introduced by…