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Dynamical bar-mode instability of differentially rotating stars: effects of equations of state and velocity profiles
| Content Provider | Paperity |
|---|---|
| Author | Shibata, Masaru Karino, Shigeyuki Eriguchi, Yoshiharu |
| Abstract | As an extension of our previous work, we investigate the dynamical instability against non-axisymmetric bar-mode deformations of differentially rotating stars in Newtonian gravity by varying the equations of state and velocity profiles. We performed the numerical simulation and the follow-up linear stability analysis by adopting polytropic equations of state with polytropic indices n= 1, 3/2 and 5/2, and with two types of angular velocity profiles (the so-called j-constant-like and Kepler-like laws). It is confirmed that rotating stars with a high degree of differential rotation are dynamically unstable against bar-mode deformation, even when the ratio of the kinetic energy to the gravitational potential energy β is of order 0.01. The criterion for the onset of bar-mode dynamical instability depends weakly on the polytropic index n and the angular velocity profile, as long as the degree of differential rotation is high. Gravitational waves from the final non-axisymmetric quasi-stationary states are calculated using the quadrupole formula. For proto-neutron stars of mass 1.4 M⊙, radius ∼30 km and β≲ 0.1, such gravitational waves have a frequency of ∼600–1400 Hz, and the effective amplitude is larger than 10−22 at a distance of about 100 Mpc, irrespective of n and the angular velocity profile. |
| Starting Page | 619 |
| Ending Page | 626 |
| File Format | HTM / HTML |
| ISSN | 00358711 |
| DOI | 10.1046/j.1365-8711.2003.06699.x |
| Issue Number | 2 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume Number | 343 |
| e-ISSN | 13652966 |
| Language | English |
| Publisher | Oxford University Press |
| Publisher Date | 2003-08-01 |
| Access Restriction | Open |
| Subject Keyword | Stars: neutron Gravitational waves Stars: oscillations Stars: rotation |
| Content Type | Text |
| Resource Type | Article |
| Subject | Astronomy and Astrophysics Space and Planetary Science |
