Abstract
We investigate the dynamical instability of the one-armed spiral m = 1 mode in differentially rotating stars by means of 3 + 1 hydrodynamical simulations in Newtonian gravitation. We find that both a soft equation of state and a high degree of differential rotation in the equilibrium star are necessary to excite a dynamical m = 1 mode as the dominant instability at small values of the ratio of rotational kinetic to gravitational potential energy, T/|W|. We find that this spiral mode propagates outward from its point of origin near the maximum density at the center to the surface over several central orbital periods. An unstable m = 1 mode triggers a secondary m = 2 bar mode of smaller amplitude, and the bar mode can excite gravitational waves. As the spiral mode propagates to the surface it weakens, simultaneously damping the emitted gravitational wave signal. This behavior is in contrast to waves triggered by a dynamical m = 2 bar instability, which persist for many rotation periods and decay only after a radiation reaction-damping timescale.
| Original language | English |
|---|---|
| Pages (from-to) | 352-364 |
| Number of pages | 13 |
| Journal | Astrophysical Journal |
| Volume | 595 |
| Issue number | 1 I |
| DOIs | |
| Publication status | Published - 2003 Sep 20 |
| Externally published | Yes |
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Keywords
- Gravitation
- Hydrodynamics
- Instabilities
- Stars: neutron
- Stars: rotation
ASJC Scopus subject areas
- Space and Planetary Science
Cite this
One-armed spiral instability in differentially rotating stars. / Saijo, Motoyuki; Baumgarte, Thomas W.; Shapiro, Stuart L.
In: Astrophysical Journal, Vol. 595, No. 1 I, 20.09.2003, p. 352-364.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - One-armed spiral instability in differentially rotating stars
AU - Saijo, Motoyuki
AU - Baumgarte, Thomas W.
AU - Shapiro, Stuart L.
PY - 2003/9/20
Y1 - 2003/9/20
N2 - We investigate the dynamical instability of the one-armed spiral m = 1 mode in differentially rotating stars by means of 3 + 1 hydrodynamical simulations in Newtonian gravitation. We find that both a soft equation of state and a high degree of differential rotation in the equilibrium star are necessary to excite a dynamical m = 1 mode as the dominant instability at small values of the ratio of rotational kinetic to gravitational potential energy, T/|W|. We find that this spiral mode propagates outward from its point of origin near the maximum density at the center to the surface over several central orbital periods. An unstable m = 1 mode triggers a secondary m = 2 bar mode of smaller amplitude, and the bar mode can excite gravitational waves. As the spiral mode propagates to the surface it weakens, simultaneously damping the emitted gravitational wave signal. This behavior is in contrast to waves triggered by a dynamical m = 2 bar instability, which persist for many rotation periods and decay only after a radiation reaction-damping timescale.
AB - We investigate the dynamical instability of the one-armed spiral m = 1 mode in differentially rotating stars by means of 3 + 1 hydrodynamical simulations in Newtonian gravitation. We find that both a soft equation of state and a high degree of differential rotation in the equilibrium star are necessary to excite a dynamical m = 1 mode as the dominant instability at small values of the ratio of rotational kinetic to gravitational potential energy, T/|W|. We find that this spiral mode propagates outward from its point of origin near the maximum density at the center to the surface over several central orbital periods. An unstable m = 1 mode triggers a secondary m = 2 bar mode of smaller amplitude, and the bar mode can excite gravitational waves. As the spiral mode propagates to the surface it weakens, simultaneously damping the emitted gravitational wave signal. This behavior is in contrast to waves triggered by a dynamical m = 2 bar instability, which persist for many rotation periods and decay only after a radiation reaction-damping timescale.
KW - Gravitation
KW - Hydrodynamics
KW - Instabilities
KW - Stars: neutron
KW - Stars: rotation
UR - http://www.scopus.com/inward/record.url?scp=0141818986&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0141818986&partnerID=8YFLogxK
U2 - 10.1086/377334
DO - 10.1086/377334
M3 - Article
AN - SCOPUS:0141818986
VL - 595
SP - 352
EP - 364
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1 I
ER -