Related papers: Stellar Orbits in Barred Galaxies with Nuclear Rin…
The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies.…
A linear analysis of baroclinic instability in a stellar radiation zone with radial differential rotation is performed. The instability onsets at a very small rotation inhomogeneity. There are two families of unstable disturbances…
In the present work we consider a diatomic granular crystal, consisting of alternating aluminum and steel spheres, where the first sphere is an aluminum one. The combination of dissipation, driving of the boundary, and intrinsic…
Secular evolution gradually shapes galaxies by internal processes, in contrast to early cosmological evolution which is more rapid. An important driver of secular evolution is the flow of gas from the disk into the central regions, often…
The back-bending phenomenon for compact stars is studied by means of analytical equations of state, for both constant-pressure phase transitions and the transitions through the mixed-phase region. We restrict ourselves to the case of normal…
State-of-the-art surveys reveal that most massive stars in the universe evolve in close binaries. Massive stars in such systems are expected to develop aspherical envelopes due to tidal interactions and/or rotational effects. Recently, it…
The radial profiles of stars in disc galaxies are observed to be either purely exponential (Type-I), truncated (Type-II) or anti-truncated (Type-III) exponentials. Controlled formation simulations of isolated galaxies can reproduce all of…
The vertical profiles of disc galaxies are built by the material trapped around stable periodic orbits, which form their "skeletons". According to this, the knowledge of the stability of the main families of periodic orbits in appropriate…
We study the dynamics of 2D and 3D barred galaxy analytical models, focusing on the distinction between regular and chaotic orbits with the help of the Smaller ALigment Index (SALI), a very powerful tool for this kind of problems. We…
The apsidal precession frequency in a fixed gravitational potential increases with the radial range of the orbit (eccentricity). Although the frequency increase is modest it can have important implications for wave dynamics in galaxy discs,…
We study the phase space structure and the orbital diffusion from the vicinity of the vertical Lyapunov periodic orbits around the unstable Lagrangian points L1,2 in a 3D barred galaxy model. By perturbing the initial conditions of these…
In the present work we have developed a three-dimensional gravitational model of barred galaxies, in order to study orbital and escape dynamics of the stars inside their central barred region. Our gravitational model is composed of four…
The orbital evolution and stability of planetary systems with interaction from the belts is studied using the standard phase-plane analysis. In addition to the fixed point which corresponds to the Keplerian orbit, there are other fixed…
The gas dynamics in the inner few kiloparsecs of barred galaxies often results in configurations that give rise to nuclear gas rings. However, the generic dynamical description of the formation of galactic nuclear rings does not take into…
The chaotic or ordered character of orbits in galactic models is an important issue, since it can influence dynamical evolution. This distinction can be achieved with the help of the Smaller Alingment Index - (SALI). We describe here…
The relative motion of stars and other celestial objects in very wide pairs, separated by distances of the order of 1 pc, is strongly influenced by the tidal gravitational potential of the Galaxy. The Coriolis component of the horizontal…
A family of periodic orbits is proven to exist in the spatial lunar problem that are continuations of a family of consecutive collision orbits, perpendicular to the primary orbit plane. This family emanates from all but two energy values.…
Disk galaxies can exchange angular momentum and baryons with their host dark matter (DM) halos. These halos possess internal spin, `lambda', which is insignificant rotationally but does affect interactions between the baryonic and DM…
We have studied the unbarred Sb galaxy with a nuclear star-forming ring, NGC 7742, by means of 2D spectroscopy, long-slit spectroscopy, and imaging, and have compared the results with the properties of another galaxy of this type, NGC 7217,…
We analyze the observed distribution of the orbital eccentricity and period of binary radio pulsars in globular clusters using computational tools to simulate binary-single star interactions. Globular clusters have different groups of…