scholarly journals Rotational and Tidal Perturbations of Nonradial Oscillations In a Polytropic Star

1980 ◽  
Vol 58 ◽  
pp. 649-652
Author(s):  
Hideyuki Saio
Keyword(s):  
Inertial Frame ◽  
Nonradial Oscillation ◽  
Tidal Perturbations ◽  
Rotating Star ◽  
Polytropic Star ◽  
Nonradial Oscillations

AbstractThe degeneracy of frequencies of nonradial oscillations is resolved in the presence of rotation. As observed in an inertial frame the frequency of a nonradial oscillation in a uniformly rotating star is given as

scholarly journals Acoustic modes of pulsating axion stars: Nonradial oscillations

2019 ◽  
Vol 28 (09) ◽  
pp. 1950111 ◽  
Author(s):  
Grigoris Panotopoulos ◽  
Ilídio Lopes
Keyword(s):  
Effective Potential ◽  
Small Frequency ◽  
Acoustic Modes ◽  
Oscillation Modes ◽  
Nonradial Oscillation ◽  
Nonradial Oscillations

We compute the lowest frequency nonradial oscillation modes of dilute axion stars. The effective potential that enters into the Schrödinger-like equation, several associated eigenfunctions and the large as well as the small frequency separations are shown as well.

scholarly journals Forced Nonradial Oscillations in Early-Type Rotating Stars

2000 ◽  
Vol 176 ◽  
pp. 376-376
Author(s):  
M. G. Witte ◽  
G. J. Savonije
Keyword(s):  
Gravitational Force ◽  
Rotation Speed ◽  
Internal Damping ◽  
Rotating Stars ◽  
Stellar Rotation ◽  
Stellar Spectrum ◽  
Coriolis Forces ◽  
Nonradial Oscillation ◽  
External Driving ◽  
Nonradial Oscillations

A method of calculating nonradial oscillations in rotating stars is presented. Using this method, we are able to calculate the spectrum of g-, f- and p-mode eigenfunctions of a star for different stellar rotation speeds, and also the spectrum of rotational r modes. Stability of the modes as a function of stellar rotation speed can be investigated. By regarding the response of a star which undergoes periodic deformations due to the gravitational force of an orbiting companion as a forced nonradial oscillation, the problem of determining the eigenfrequencies of the star becomes one of finding resonances with the forcing potential. Expanding the potential of the orbiting (point mass) companion in terms of the usual spherical functions, the response of the star to each tidal term , with l and m fixed, can be calculated separately. By varying the forcing frequency σ we are then able to calculate the stellar spectrum. To calculate the response of the star we numerically solve the fully non-adiabatic, but linearised hydrodynamical equations for the star, in which the Coriolis forces due to stellar rotation are fully taken into account. To this end we utilise an implicit 2D finite difference scheme which solves the equations on an (r, ϑ) grid. A calculated solution describes the steady state in which the power σT due to the external driving force is in equilibrium with the internal damping. For results and more references see Witte & Savonije (1999).

Design and Development of an Inertial Frame Displacement Gauge

1987 ◽  
Author(s):  
F. C. Ford ◽  
C. T. Vincent ◽  
T. Gaines ◽  
R. Frazen
Keyword(s):  
Inertial Frame ◽  
Design And Development

Galilean Relativity

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
Inertial Frame ◽  
Vertical Component ◽  
Horizontal Component ◽  
The Other ◽  
One Dimension ◽  
Everyday Experience ◽  
Low Speed ◽  
Principle Of Relativity ◽  
Galilean Relativity ◽  
Laws Of Motion

Galilean relativity is a useful description of nature at low speed. Galileo found that the vertical component of a projectile’s velocity evolves independently of its horizontal component. In a frame that moves horizontally along with the projectile, for example, the projectile appears to go straight up and down exactly as if it had been launched vertically. The laws of motion in one dimension are independent of any motion in the other dimensions. This leads to the idea that the laws of motion (and all other laws of physics) are equally valid in any inertial frame: the principle of relativity. This principle implies that no inertial frame can be considered “really stationary” or “really moving.” There is no absolute standard of velocity (contrast this with acceleration where Newton’s first law provides an absolute standard). We discuss some apparent counterexamples in everyday experience, and show how everyday experience can be misleading.

scholarly journals Broadband Linear Polarization in Ap Stars

1993 ◽  
Vol 138 ◽  
pp. 305-309
Author(s):  
Marco Landolfi ◽  
Egidio Landi Degl’Innocenti ◽  
Maurizio Landi Degl’Innocenti ◽  
Jean-Louis Leroy ◽  
Stefano Bagnulo
Keyword(s):  
Magnetic Field ◽  
Circular Polarization ◽  
Linear Polarization ◽  
Rotation Axis ◽  
Spectral Lines ◽  
Line Of Sight ◽  
Long Time ◽  
Rotating Star ◽  
Ap Stars ◽  
The Magnetic Field

AbstractBroadband linear polarization in the spectra of Ap stars is believed to be due to differential saturation between σ and π Zeeman components in spectral lines. This mechanism has been known for a long time to be the main agent of a similar phenomenon observed in sunspots. Since this phenomenon has been carefully calibrated in the solar case, it can be confidently used to deduce the magnetic field of Ap stars.Given the magnetic configuration of a rotating star, it is possible to deduce the broadband polarization at any phase. Calculations performed for the oblique dipole model show that the resulting polarization diagrams are very sensitive to the values of i (the angle between the rotation axis and the line of sight) and β (the angle between the rotation and magnetic axes). The dependence on i and β is such that the four-fold ambiguity typical of the circular polarization observations ((i,β), (β,i), (π-i,π-β), (π-β,π-i)) can be removed.

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