Related papers: Enhanced magnetic activity in rapidly rotating bin…
Many stars, including those in binary or multiple systems, exhibit modified rotational evolution due to tidal interactions. While magnetic braking slows rotation in single stars, close binaries experience synchronization from tidal forces,…
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…
Context. Fast rotating red giants in the upper part of the red giant branch have surface velocities that cannot be explained by single star evolution. Aims. We check whether tides between a star and a planet followed by planet engulfment…
Tidal interactions play an important role in the evolution and ultimate fate of compact white dwarf (WD) binaries. Not only do tides affect the pre-merger state (such as temperature and rotation rate) of the WDs, but they may also determine…
We discuss possible mechanisms underlying the observed features of stellar activity cycles, such as multiple periodicities in very active stars, non-cyclic activity observed in moderately active stars, and spatial distribution of stellar…
Surface reconstructions of active close binary stars based on photometric and spectroscopic observations reveal non-uniform starspot distributions, which indicate the existence of preferred spot longitudes (with respect to the companion…
Using the homogeneous X-ray catalog from ROSAT observations, we conducted a comprehensive investigation into stellar X-ray activity-rotation relations for both single and binary stars. Generally, the relation for single stars consists of…
Since twenty years, a large population of close-in planets orbiting various classes of low-mass stars (from M to A-type stars) has been discovered. In such systems, the dissipation of the kinetic energy of tidal flows in the host star may…
We conduct one-dimensional stellar evolutionary numerical simulations under the assumption that an efficient dynamo operates in the core of massive stars years to months before core collapse and find that the magnetic activity enhances mass…
The magnetic activity of the Sun becomes stronger and weaker over roughly an 11 year cycle, modulating the radiation and charged particle environment experienced by the Earth as "space weather". Decades of observations from the Mount Wilson…
Tidal interaction is a major ingredient in the theory of binary evolution. Here, we study tidal circularization in binaries with red giant primaries. We compute the tidal evolution for binaries as their primary stars evolve along the red…
The combination of asteroseismologically-measured masses with abundances from detailed analyses of stellar atmospheres challenges our fundamental knowledge of stars and our ability to model them. Ancient red-giant stars in the Galactic…
Previous studies have found that red giants (RGs) in close binary systems undergoing spin-orbit resonance exhibit an enhanced level of magnetic activity with respect to single RGs rotating at the same rate, from measurements of photometric…
Tidal dissipation is responsible for circularizing the orbits and synchronizing the spins of solar-type close binary stars, but the mechanisms responsible are not fully understood. Previous work has indicated that significant enhancements…
Planets orbiting young, solar-type stars are embedded in a more energetic environment than that of the solar neighbourhood. They experience harsher conditions due to enhanced stellar magnetic activity and wind shaping the secular evolution…
Luminous X-ray stars are very often found in visual double or multiple stars. Binaries with periods of a few days possess the highest degree of coronal X-ray activity among regular, non-relativistic stars because of their fast, tidally…
The tidal interactions of planets affect the stellar evolutionary status and the constraint of their physical parameters by gyrochronology. In this work, we incorporate the tidal interaction and magnetic braking of the stellar wind into…
Rapid rotation enhances the dynamo operating in stars, and thus also introducessignificantly stronger magnetic activity than is seen in slower rotators. Many young cool stars still have the rapid, primordial rotation rates induced by the…
Evolution of binary objects under the influence of tides drastically affects the expected observational properties of the system. With the discovery of a large number of close-in hot Jupiter systems and eclipsing binaries from missions such…
The angular momentum (AM) evolution of stellar interiors, along with the resulting rotation rates of stellar remnants, remains poorly understood. Asteroseismic measurements of red giant stars reveal that their cores rotate much faster than…