English
Related papers

Related papers: Bisymmetric normal modes in soft-centred and reali…

200 papers

We analytically calculate the marginally stable surface density profile for rotational instability of protoplanetary disks. The derived profile can be utilized for considering the region in a rotating disk where radial pressure gradient…

Earth and Planetary Astrophysics · Physics 2014-07-11 Tomohiro Ono , Hideko Nomura , Taku Takeuchi

Determining the mass of stars is crucial both to improving stellar evolution theory and to characterising exoplanetary systems. Asteroseismology offers a promising way to estimate stellar mean density. When combined with accurate radii…

Solar and Stellar Astrophysics · Physics 2015-06-03 D. R. Reese , J. P. Marques , M. J. Goupil , M. J. Thompson , S. Deheuvels

An asymptotic method for finding instabilities of arbitrary $d$-dimensional large-amplitude patterns in a wide class of reaction-diffusion systems is presented. The complete stability analysis of 2- and 3-dimensional localized patterns is…

patt-sol · Physics 2009-10-30 C. B. Muratov , V. V. Osipov

Spectroastrometry is a technique which has the potential to resolve flux distributions on scales of milliarcseconds. In this study, we examine the application of spectroastrometry to binary point sources which are spatially unresolved due…

Astrophysics · Physics 2009-11-10 John M. Porter , Rene D. Oudmaijer , Debbie Baines

This paper studies the oscillatory stability of uniformly rotating main-sequence stars of mass 3-8 M_sun by solving the linearized non-adiabatic, non-radial oscillation equations with a forcing term and searching for resonant response to a…

Astrophysics · Physics 2009-11-11 G. J. Savonije

The paper studies a geometrically unfitted finite element method (FEM), known as trace FEM or cut FEM, for the numerical solution of the Stokes system posed on a closed smooth surface. A trace FEM based on standard Taylor-Hood (continuous…

Numerical Analysis · Mathematics 2020-04-13 Maxim A. Olshanskii , Arnold Reusken , Alexander Zhiliakov

We prove that the two-step backward differentiation formula (BDF2) method is stable on arbitrary time grids; while the variable-step BDF3 scheme is stable if almost all adjacent step ratios are less than 2.553. These results relax the…

Numerical Analysis · Mathematics 2023-01-31 Zhaoyi Li , Hong-lin Liao

The popularity of local meshless methods in the field of numerical simulations has increased greatly in recent years. This is mainly due to the fact that they can operate on scattered nodes and that they allow a direct control over the…

Numerical Analysis · Mathematics 2022-06-29 Mitja Jančič , Gregor Kosec

We use oblate axisymmetric dynamical models including dark halos to determine the orbital structure of intermediate mass to massive Coma early-type galaxies. We find a large variety of orbital compositions. Averaged over all sample galaxies…

We review the difficulties of the classical fission and fragmentation hypotheses for the formation of binary and multiple stars. A crucial missing ingredient in previous theoretical studies is the inclusion of dynamically important levels…

Astrophysics · Physics 2009-10-31 Daniele Galli , Frank H. Shu , Gregory Laughlin , Susana Lizano

In this review, I discuss just three aspects of the stability and evolution of galactic discs. (1) I first review our understanding of the bar instability and how it can be controlled. Disc galaxies in which the orbital speed does not…

Astrophysics · Physics 2007-05-23 J. A. Sellwood

Studying time-dependent behavior in lasers is analytically difficult due to the saturating non-linearity inherent in the Maxwell-Bloch equations and numerically demanding because of the computational resources needed to discretize both time…

Optics · Physics 2015-12-23 O. Malik , K. G. Makris , H. E. Türeci

When numerically solving partial differential equations (PDEs), the first step is often to discretize the geometry using a mesh and to solve a corresponding discretization of the PDE. Standard finite and spectral element methods require…

Analysis of PDEs · Mathematics 2018-03-30 Aaron Yeiser , Advisor Alex Townsend

In earlier papers in this series we determined the intrinsic stellar disc kinematics of fifteen intermediate to late type edge-on spiral galaxies using a dynamical modeling technique. From the photometry we find that intrinsically more…

Astrophysics · Physics 2009-11-10 M. Kregel , P. C. van der Kruit , K. C. Freeman

The diabatic approach to collective nuclear motion is reformulated in the local-density approximation in order to treat the normal modes of a spherical nuclear droplet analytically. In a first application the adiabatic isoscalar modes are…

Nuclear Experiment · Physics 2009-10-31 W. Noerenberg , G. Papp , P. Rozmej

The discrete kinetic model is used to study the propagation of sound waves in system of hard-disk-like rotating stars (or vortex gases). The anomalous (negative) attenuation or amplification which is possibly due to the binary collision of…

Astrophysics · Physics 2008-09-07 Zhu Guang Hua

We consider spectral mixed discontinuous Galerkin finite element discretizations of the Lam\'e system of linear elasticity in polyhedral domains in $\mathbb{R}^3$. In order to resolve possible corner, edge, and corner-edge singularities,…

Numerical Analysis · Mathematics 2019-08-14 Thomas P. Wihler , Marcel Wirz

The linear instability of thin, vertically-isothermal Keplerian discs, under the influence of axial magnetic field is investigated. Solutions of the stability problem are found explicitly by asymptotic expansions in the small aspect ratio…

Solar and Stellar Astrophysics · Physics 2015-06-03 E. Liverts , Yu. Shtemler , M. Mond

We present a semi-analytical point-dipole method that uses Ewald lattice summation to find the dispersion relation of guided plasmonic and bianisotropic modes in metasurfaces composed of 2D periodic lattices of arbitrarily strongly…

Optics · Physics 2015-06-23 Per Lunnemann , A. Femius Koenderink

Diffraction methods are at the heart of structure determination of solids. While Bragg-like scattering (pure point diffraction) is a characteristic feature of crystals and quasicrystals, it is not straightforward to interpret continuous…

Mathematical Physics · Physics 2009-06-26 Michael Baake , Uwe Grimm