Related papers: A pre-Caloris synchronous rotation for Mercury
The orientation of a massive binary undergoes a random walk due to gravitational encounters with field stars. The rotational diffusion coefficient for a circular-orbit binary is derived via scattering experiments. The binary is shown to…
We investigate the stability of prograde versus retrograde planets in circular binary systems using numerical simulations. We show that retrograde planets are stable up to distances closer to the perturber than prograde planets. We develop…
Asteroids in mean motion resonances with giant planets are common in the solar system, but it was not until recently that several asteroids in retrograde mean motion resonances with Jupiter and Saturn were discovered. A retrograde…
Crust quakes are frequently invoked as a mechanism to trigger sudden transients in the magnetospheres of magnetars. In this picture, a mechanical failure of the crust excites seismic motions of the magnetar surface that launch force-free…
In a recent paper it was reported a planetary system around the star HD60532, composed by two giant planets in a possible 3:1 mean motion resonance, that should be confirmed within the next decade. Here we show that the analysis of the…
Transiting circumbinary planets (CBPs) are conspicuously rare, and entirely absent around stellar binaries with periods $\leq 7$ days. Here, we exploit a secular resonance to stimulate the orbit of a CBP into strong, disruptive interactions…
The evolution under radiation backreaction of a binary system consisting of a black hole and a companion is studied in the limiting case when the spin of the companion is negligible compared with the spin S of the black hole. To first order…
The propeller regime of disk accretion to a rapidly rotating magnetized star is investigated here for the first time by axisymmetric 2.5D magnetohydrodynamic simulations. An expanded, closed magnetosphere forms in which the magnetic field…
The origin of the spins of giant planets is an open question in astrophysics. As planets and stars accrete from discs, if the specific angular momentum accreted corresponds to that of a Keplerian orbit at the surface of the object, it is…
Convergent migration involving multiple planets embedded in a viscous protoplanetary disc is expected to produce a chain of planets in mean motion resonances, but the multiplanet systems observed by the Kepler spacecraft are generally not…
The record of reversals of the geomagnetic field has played an integral role in the development of plate tectonic theory. Statistical analyses of the reversal record are aimed at detailing patterns and linking those patterns to core-mantle…
Millisecond pulsars are old neutron stars that have been spun up to high rotational frequencies via accretion of mass from a binary companion star. An important issue for understanding the physics of the early spin evolution of millisecond…
The Kepler space mission discovered about a dozen planets orbiting around binary stars systems. Most of these circumbinary planets lie near their instability boundaries at about 3 to 5 binary separations. Past attempts to match these final…
The early stages of dynamical evolution of planetary systems are often shaped by dissipative processes that drive orbital migration. In multi-planet systems, convergent amassing of orbits inevitably leads to encounters with rational period…
Orbits of known extrasolar planets that are located outside the tidal circularization regions of their parent stars are often substantially eccentric. By contrast, planetary orbits in our Solar System are approximately circular, reflecting…
The K2-138 system hosts six planets and presents an interesting case study due to its distinctive dynamical structure. Its five inner planets are near a chain of 3/2 two-body mean-motion resonances, while the outermost body (planet {\it g})…
Most close-in planetary satellites are in synchronous rotation, which is usually the stable end-point of tidal despinning. Saturn's moon Hyperion is a notable exception by having a chaotic rotation. Hyperion's dynamical state is a…
We investigate the resonant rotation of circumbinary bodies in planar quasi-circular orbits. Denoting $n_b$ and $n$ the orbital mean motion of the inner binary and of the circumbinary body, respectively, we show that spin-orbit resonances…
Massive stars with solar metallicity lose important amounts of rotational angular momentum through their winds. When a magnetic field is present at the surface of a star, efficient angular momentum losses can still be achieved even when the…
The spin-down power of a pulsar is thought to be carried away in an MHD wind in which, at least close to the star, the energy transport is dominated by Poynting flux. The pulsar drives a low-frequency wave in this wind, consisting of…