Local Axisymmetric Instability Criterion in the Thin , Rotating , Multicomponent Disk
نویسنده
چکیده
Purely gravitational perturbations are considered in a thin rotating disk composed of several gas and stellar components. The dispersion relation for the axisymmetric density waves propagating through the disk is found and the criterion for the local axisymmetric stability of the whole system is formulated. In the appropriate limit of two-component gas we confirm the findings of Jog & Solomon (1984) and extend consideration to the case when one component is collisionless. Gravitational stability of the Galactic disk in the Solar neighborhood based on the multicomponent instability condition is explored using recent measurements of the stellar composition and kinematics in the local Galactic disk obtained by Hipparcos satellite.
منابع مشابه
Local stability criterion for a gravitating disk of stars
Computer N -body experiments are desribed which test the validities of the original Toomre’s (1964) criterion and of a generalized criterion for local stability of Jeans-type perturbations in a self-gravitating, infinitesimally thin, and practically collisionless disk of stars. The fact that the nonaxisymmetric perturbations in the differentially rotating system are more unstable than the axisy...
متن کاملMagneto-Thermo-Elastic Stresses and Perturbation of Magnetic Field Vector in a Thin Functionally Graded Rotating Disk
In this paper, a semi-analytical solution for magneto-thermo-elastic problem in an axisymmetric functionally graded (FG) hollow rotating disk with constant thickness placed in uniform magnetic and thermal fields with heat convection from disk’s surfaces is presented. Solution for stresses and perturbation of magnetic field vector in a thin FG rotating disk is determined using infinitesimal theo...
متن کاملLocal stability criterion for self-gravitating disks in modified gravity
We study local stability of self-gravitating fluid and stellar disk in the context of modified gravity theories which predict a Yukawa-like term in the gravitational potential of a point mass. We investigate the effect of such a Yukawa-like term on the dynamics of self-gravitating disks. More specifically, we investigate the consequences of the presence of this term for the local stability of t...
متن کاملAxisymmetric Bending Oscillations of Stellar Disks
Self-gravitating stellar disks with random motion support both exponentially growing and, in some cases, purely oscillatory axisymmetric bending modes, unlike their cold disk counterparts. A razor-thin disk with even a very small degree of random motion in the plane is both unstable and possesses a discrete spectrum of neutral modes, irrespective of the sharpness of the edge. Random motion norm...
متن کاملStability of Toomre-Hayashi Disk
We investigate stability of Toomre-Hayashi model for a self-gravitating, rotating gas disk. The rotation velocity, vφ, and sound speed, cs, are spatially constant in the model. We show that the model is unstable against an axisymmetric perturbation irrespectively of the values of vφ and cs. When the ratio, vφ/cs, is large, the model disk is geometrically thin and unstable against an axisymmetri...
متن کامل