Related papers: Late-Time Behavior of Stellar Collapse and Explosi…
Glitches have been frequently observed in neutron stars. Previously these glitches unexceptionally manifest as sudden spin-ups that can be explained as due to impulsive transfer of angular momentum from the interior superfluid component to…
We consider a sequence of blowup solutions of a two dimensional, second order elliptic equation with exponential nonlinearity and singular data. This equation has a rich background in physics and geometry. In a work of…
We report a phenomenon of phase separation that relates in many aspects to Yves Couder's work: an inflatable architectured elastomer plate, expected to expand homogeneously in its plane, buckles instead widely out-of-plane into very complex…
Star formation within filaments may arise due to the growth of cores according to linear perturbation theory. This implies a minimum core separation, as shorter modes would not be able to grow. While many observations agree with core…
Growing experimental evidence indicates that topological defects could serve as organizing centers in the morphogenesis of tissues. Here, we provide a quantitative explanation for this phenomenon, rooted in the buckling theory of deformable…
The effect of stellar aberration seems to be one of the simplest phenomena in astronomical observations. But there is a large literature about it betraying a problem of asymmetry between observer motion and source motion. This paper…
Neutron stars or pulsars are very rapidly rotating compact stars with extremely high density. One of the unsolved long-standing problems of these enigmatic celestial bodies is the origin of pulsars' glitches, i.e., the sudden rapid…
Both analytic and numerical radiative transfer models applied to high spectral resolution CS and N2H+ data give insight into the evolutionary state of L1551 MC. This recently discovered pre-protostellar core in L1551 appears to be in the…
We propose a new approach to the study of (nonlinear) growth and instability for semilinear evolution equations with compact nonlinearities. We show, in particular, that compact nonlinear perturbations of a linear evolution equation can be…
Planetary systems can evolve dynamically even after the planets themselves have fully formed, and there is circumstantial evidence that most planetary systems become unstable after the disappearance of the gaseous protoplanetary disk.…
In the theoretical biology framework one fundamental problem is the so-called error catastrophe in Darwinian evolution models. We reexamine Eigen's fundamental equations by mapping them into a polymer depinning transition problem in a…
We show that interactions violating the conservation of lepton numbers in the neutrino sector could significantly alter the standard low entropy picture for the pre-supernova collapsing core of a massive star. A rapid neutrino-antineutrino…
Recent observations have revealed the presence of a variety of small-scale ``micro-structures'' in Planetary Nebulae images. I discuss numerical hydrodynamics models of planetaries and outline the formation and growth of instabilities that…
Recent fully non-linear simulations of ultracompact spherically symmetric boson stars have presented evidence for their long-term stability. All observed dynamics could be mainly attributed to the fundamental radial mode. In this work, we…
Ionization front instabilities have long been of interest for their suspected role in a variety of phenomena in the galaxy, from the formation of bright rims and 'elephant trunks' in nebulae to triggered star formation in molecular clouds.…
Consider at a finite temperature $T$ a superfluid moving with a velocity $v$ relative to the thermal bath or its normal component. From Landau's argument there exists a critical $v_c (T)$ beyond which excitations can be spontaneously…
The dynamics of galactic nuclei can be affected by several mechanisms. Among these are stellar evolution, stellar collisions, mass segregation, and tidal disruptions of stars due to the central black hole. In this presentation I will…
The conditions under which stable evolution of two nonlinear interacting waves are derived within the context of nematic crystals. Two cases are considered: plane waves and solitons. In the first case, the modulation instability analysis…
If the split, asymmetric molecular spectral line profiles that are seen in many starless cores are interpreted as indicative of global collapse or expansion of the core then one possible implication is that most starless cores have short…
The evolution of a protostellar binary system is investigated while it is embedded in its parent molecular cloud core and acted upon by gas drag due to dynamical friction. Approximate analytical results are obtained for the energy and…