Related papers: X-ray emission from pre-main sequence stars with m…
Although, from a theoretical point of view, magnetic fields are believed to have a significant role during the early stages of star formation, especially during the main accretion phase, the magnetic field strength and topology is poorly…
Late-type main sequence stars exhibit an x-ray to bolometric flux ratio that depends on ${\tilde Ro}$, the ratio of rotation period to convective turnover time, as ${\tilde Ro}^{-\zeta}$ with $2\le \zeta \le 3$ for ${\tilde Ro} >0.13$, but…
Context. gamma Doradus (gamma Dor) are late A and F-type stars pulsating with high order gravity modes (g-modes). The existence of different evolutionary phases crossing the gamma Dor instability strip raises the question of the existence…
For main-sequence stars beyond spectral type M5 the characteristics of magnetic activity common to warmer solar-like stars change into the brown-dwarf domain: the surface magnetic field becomes more dipolar and the evolution of the field…
Theories on the origin of magnetic fields in massive stars remain poorly developed, because the properties of their magnetic field as function of stellar parameters could not yet be investigated. To investigate whether magnetic fields in…
Aims: Our aim is to understand the evolutionary sequence of high-mass star formation from the earliest evolutionary stage of high-mass starless cores, via high-mass cores with embedded low- to intermediate-mass objects, to finally high-mass…
The structure of a star's coronal magnetic field is a fundamental property that governs the high-energy emission from the hot coronal gas and the loss of mass and angular momentum in the stellar wind. It is, however, extremely difficult to…
The spatial and spectral properties of three solar flare coronal X-ray loops are studied before, during and after the peak X-ray emission. Using observations from the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), we deduce the…
We propose a unified picture of high magnetic field radio pulsars and magnetars by arguing that they are all rotating high-field neutron stars, but have different orientations of their magnetic axes with respective to their rotation axes.…
Persistent activity of magnetars is associated with electric discharge that continually injects relativistic particles into the magnetosphere. Large active magnetic loops around magnetars must be filled with outflowing particles that…
Magnetars are highly magnetized neutron stars that can produce X-ray and soft gamma-ray emissions and that have a dipole of $10^{14}$ G to $10^{15}$ G. A promising mechanism for explaining magnetar formation is magnetic field amplification…
Our theoretical and numerical analysis have suggested that for low-mass main sequences stars (of the spectral classes from M5 to G0) rotating much faster than the Sun, the generated large-scale magnetic field is caused by the mean-field…
The intense magnetic fields of neutron stars naturally lead to strong anisotropy and polarization of radiation emanating from their surfaces, both being sensitive to the hot spot position on the surface. Accordingly, pulse phase-resolved…
The accretion flow within the magnetospheric radius of bright X-ray pulsars can form an optically thick envelope, concealing the central neutron star from the distant observer. Most photons are emitted at the surface of a neutron star and…
Strong multi-kilotesla magnetic fields have various applications in high-energy density science and laboratory astrophysics, but they are not readily available. In our previous work [Y. Shi et al., Phys. Rev. Lett. 130, 155101 (2023)], we…
We report new magnetic field measurements for 14 classical T Tauri stars (CTTSs). We combine these data with one previous field determination in order to compare our observed field strengths with the field strengths predicted by…
We discuss selected aspects regarding the magnetic field evolution of solar-type stars. Most of the stars with activity cycles are in the range where the normalized chromospheric Calcium emission increases linearly with the inverse Rossby…
Surface magnetic fields have a strong impact on stellar mass loss and rotation and, as a consequence, on the evolution of massive stars. In this work we study the influence of an evolving dipolar surface fossil magnetic field with an…
Because of the unquestionable presence of magnetic fields in stars, their role in the structure of stellar atmospheres has for a long time been a subject of speculation. In our contribution to this discussion we present spectropolarimetric…
As a massive star evolves through multiple stages of nuclear burning on its way to becoming a supernova, a complex, differentially rotating structure is set up. Angular momentum is transported by a variety of classic instabilities, and also…