Related papers: Self-Gravity and Dissipation in Polar Rings
We have searched for CO lines in a sample of 21 new morphologically determined polar-ring galaxies (of which nine are kinematically confirmed), obtained from a wide search in the Galaxy Zoo project by Moiseev and collaborators. Polar-ring…
After the first prediction to expect geodetic precession in binary pulsars in 1974, made immediately after the discovery of a pulsar with a companion, the effects of relativistic spin precession have now been detected in all binary systems…
Rapid inflows associated with early galaxy formation lead to the accumulation of self-gravitating gas in the centers of proto-galaxies. Such gas accumulations are prone to non-axisymmetric instabilities, as in the well-known Maclaurin…
We initiate numerical studies of differentially rotating magnetised (proto) neutron stars by studying - through construction from first principles - the coupling between an assumed differential rotation and an impressed magnetic field. For…
We analyze the dynamics of individual kilometer-size planetesimals in circumstellar orbits of a tight binary system. We include both the gravitational perturbations of the secondary star and a non-linear gas drag stemming from an eccentric…
We investigate the formation mechanism for the observed nearly polar aligned (perpendicular to the binary orbital plane) debris ring around the eccentric orbit binary 99 Herculis. An initially inclined nonpolar debris ring or disc will not…
Motivated by the nonlinear star formation efficiency found in recent numerical simulations by a number of workers, we perform high-resolution adaptive mesh refinement simulations of star formation in self-gravitating turbulently driven gas.…
Time-dependent meridional circulation and differential rotation in radiative zones are central open issues in stellar evolution theory. We streamline this challenging problem using the downward control principle of atmospheric science,…
The circular velocities of the inner region of disk galaxies are predicted by standard physics but velocities beyond the stellar disks are not consistent with Newtonian physics if the material there is in stable circular orbits. However,…
Relativistic stars are endowed with intense electromagnetic fields but are also subject to oscillations of various types. We here investigate the impact that oscillations have on the electric and magnetic fields external to a relativistic…
The collapse of singular magnetized toroids (Li & Shu 1996) is a natural representation of an early phase in star formation, bridging the prestellar and protostellar phases of the collapse of molecular cloud cores. We revisit the collapse…
While planets in the solar system only have a low inclination with respect to the ecliptic there is mounting evidence that in extrasolar systems the inclination can be very high, at least for close-in planets. One process to alter the…
We have used a set of equations developed by Pringle (1992) to follow the evolution of a viscous twisted disk in a galaxy-like potential which is stationary or tumbling relative to inertial space. In an axisymmetric potential, the disk…
We suggest that polar rings and/or counter-rotating disks in flattened galaxies can be formed from stars captured at the Binney resonance, where the rate of precession of the angular momentum vector of a disk star equals the pattern speed…
A self-similar solution for time evolution of isothermal, self-gravitating viscous disks is found under the condition that $\alpha' \equiv \alpha (H/r)$ is constant in space (where $\alpha$ is the viscosity parameter and $H/r$ is the ratio…
We investigate the long-term and large-scale viscous evolution of dense planetary rings using a simple 1D numerical code. We use a physically realistic viscosity model derived from N-body simulations (Daisaka et al., 2001), and dependent on…
Growth rates for gravitational instabilities in a thick disk of gas and stars are determined for a turbulent gas that dissipates on the local crossing time. The scale heights are derived from vertical equilibrium. The accuracy of the usual…
Abridged: We use three-dimensional SPH simulations to investigate the collapse of low-mass prestellar cores and the formation and early evolution of protostellar discs. The initial conditions are slightly supercritical Bonnor-Ebert spheres…
We present an analysis of structural features of all known galaxies with optical polar rings. We find a clear dichotomy for objects of this peculiar class. Bulge-dominated S0 galaxies possess only short narrow rings, while disk-dominated…
Internal gravity waves propagate in stellar radiative zones and transport angular momentum throughout the evolution of stars, shaping the internal rotation pro le of these regions. We use the analytical study of Andre\'e et al. (2018) to…