Related papers: Jupiter Mass Binaries and Cosmic Ray Viscosity
(abridged) Sub-stellar mass objects have fundamentally different binary properties than stars implying that they cannot have the same formation history. They are rather unfinished stars having either been ejected by their siblings from…
Jupiter's fast rotation - one rotation over 10 hours - creates strong jet streams, smearing its clouds into linear bands of dark and light zonal belts that circle the planet on lines of almost constant latitude. Such a high degree of…
We have recently presented observational evidence which suggests that the origin of the second generation (G2) stars in globular clusters (GCs) is due to the binary-mediated collision of primordial (G1) low-mass main-sequence (MS) stars.…
We explain the emergence and stability of the most important jets and vortices, in the highly turbulent Jupiter's atmosphere, by a statistical mechanics of the potential vorticity mixing. Using the Quasi-Geostrophic 1-1/2 layer, with…
Stars are, generically, rotating and magnetised objects with a misalignment between their magnetic and rotation axes. Since a magnetic field induces a permanent distortion to its host, it provides effective rigidity even to a fluid star,…
The frequency of low-mass pre-main sequence binary systems is significantly lower in the Trapezium Cluster than in Taurus-Auriga. We investigate if this difference can be explained through stellar encounters in dense clusters. To this…
We discuss the effects of the magnetic field observed in molecular clouds on the process of star formation, concentrating on the phase of gravitational collapse of low-mass dense cores, cradles of sunlike stars. We summarize recent analytic…
Existence of planets is binaries with relatively small separations (around 20 AU), such as \alpha Centauri or \gamma Cephei poses severe challenges to standard planet formation theories. The problem lies in the vigorous secular excitation…
The existence of planets born in environments highly perturbed by a stellar companion represents a major challenge to the paradigm of planet formation. In numerical simulations, the presence of a close binary companion stirs up the relative…
We investigate the formation of brown dwarfs and very low-mass stars through the gravitational fragmentation of infalling gas into stellar clusters. The gravitational potential of a forming stellar cluster provides the focus that attracts…
We study binary stars moving through a uniform dark matter background and experiencing dynamical friction. The centre-of-mass motion of the pairs is taken into account. We derive formulas and timescales for the secular evolution of the…
We determine the properties of the stellar torus that we showed in a previous paper to result as a product of two merging black holes. If the surrounding stellar cluster is as massive as the binary black hole, the torque acting on the stars…
It is generally accepted that neutron stars form in core collapse events that are accompanied by a supernovae (types II or Ib or Ic). Typical progenitors are, therefore, larger than $\sim 2.1 \Ms$. We suggest \cite{PS04,PS05} that the…
It is now established that the hot Jupiters have extensive gaseous (ionospheric) envelopes, which expanding far beyond the Roche lobe. The envelopes are weakly bound to the planet and affected by strong influence of stellar wind…
We discuss steady viscous Keplerian decretion discs around rapidly rotating stars. We assume that low frequency modes, which may be excited by the opacity bump mechanism, convective motion in the core, or tidal force if the star is in a…
There are two planetary formation scenarios: core accretion and gravitational disk instability. Based on the fact that gaseous objects are preferentially observed around metal-rich host stars, most extra-solar gaseous objects discovered to…
Recently several gravitational wave detections have shown evidence for compact object mergers. However, the astrophysical origin of merging binaries is not well understood. Stellar binaries are typically at much larger separations than what…
A large fraction of stars are in binary systems, yet the evolution of proto-planetary discs in binaries has been little explored from the theoretical side. In this paper we investigate the evolution of the discs surrounding the primary and…
A particle orbiting a misaligned eccentric orbit binary undergoes nodal precession either around the binary angular momentum vector (a circulating orbit) or around a stationary inclination (a librating orbit). In the absence of general…
This paper uses statistical and $N$-body methods to explore a new mechanism to form binary stars with extremely large separations ($> 0.1\,{\rm pc}$), whose origin is poorly understood. Here, ultra-wide binaries arise via chance entrapment…