### Abstract

We use a perturbation method to study gravitational waves from a spinning test particle scattered by a relativistic star. The present analysis is restricted to axial modes. By calculating the energy spectrum, the wave forms, and the total energy and angular momentum of gravitational waves, we analyze the dependence of the emitted gravitational waves on particle spin. For a normal neutron star, the energy spectrum has one broad peak whose characteristic frequency corresponds to the angular velocity at the turning point (a periastron). Since the turning point is determined by the orbital parameter, there exists a dependence of the gravitational wave on particle spin. We find that the total energy of 1=2 gravitational waves gets larger as the spin increases in the antiparallel direction to the orbital angular momentum. For an ultracompact star, in addition to such an orbital contribution, we find the quasinormal modes excited by a scattered particle, whose excitation rate to gravitational waves depends on the particle spin. We also discuss the ratio of the total angular momentum to the total energy of gravitational waves and explain its spin dependence.

Original language | English |
---|---|

Article number | 124012 |

Journal | Physical Review D |

Volume | 63 |

Issue number | 12 |

DOIs | |

Publication status | Published - 2001 |

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### ASJC Scopus subject areas

- Physics and Astronomy (miscellaneous)
- Physics and Astronomy(all)
- Nuclear and High Energy Physics
- Mathematical Physics

### Cite this

*Physical Review D*,

*63*(12), [124012]. https://doi.org/10.1103/PhysRevD.63.124012

**Gravitational waves from a spinning particle scattered by a relativistic star : Axial mode case.** / Tominaga, Kazuhiro; Saijo, Motoyuki; Maeda, Keiichi.

Research output: Contribution to journal › Article

*Physical Review D*, vol. 63, no. 12, 124012. https://doi.org/10.1103/PhysRevD.63.124012

}

TY - JOUR

T1 - Gravitational waves from a spinning particle scattered by a relativistic star

T2 - Axial mode case

AU - Tominaga, Kazuhiro

AU - Saijo, Motoyuki

AU - Maeda, Keiichi

PY - 2001

Y1 - 2001

N2 - We use a perturbation method to study gravitational waves from a spinning test particle scattered by a relativistic star. The present analysis is restricted to axial modes. By calculating the energy spectrum, the wave forms, and the total energy and angular momentum of gravitational waves, we analyze the dependence of the emitted gravitational waves on particle spin. For a normal neutron star, the energy spectrum has one broad peak whose characteristic frequency corresponds to the angular velocity at the turning point (a periastron). Since the turning point is determined by the orbital parameter, there exists a dependence of the gravitational wave on particle spin. We find that the total energy of 1=2 gravitational waves gets larger as the spin increases in the antiparallel direction to the orbital angular momentum. For an ultracompact star, in addition to such an orbital contribution, we find the quasinormal modes excited by a scattered particle, whose excitation rate to gravitational waves depends on the particle spin. We also discuss the ratio of the total angular momentum to the total energy of gravitational waves and explain its spin dependence.

AB - We use a perturbation method to study gravitational waves from a spinning test particle scattered by a relativistic star. The present analysis is restricted to axial modes. By calculating the energy spectrum, the wave forms, and the total energy and angular momentum of gravitational waves, we analyze the dependence of the emitted gravitational waves on particle spin. For a normal neutron star, the energy spectrum has one broad peak whose characteristic frequency corresponds to the angular velocity at the turning point (a periastron). Since the turning point is determined by the orbital parameter, there exists a dependence of the gravitational wave on particle spin. We find that the total energy of 1=2 gravitational waves gets larger as the spin increases in the antiparallel direction to the orbital angular momentum. For an ultracompact star, in addition to such an orbital contribution, we find the quasinormal modes excited by a scattered particle, whose excitation rate to gravitational waves depends on the particle spin. We also discuss the ratio of the total angular momentum to the total energy of gravitational waves and explain its spin dependence.

UR - http://www.scopus.com/inward/record.url?scp=0034890203&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034890203&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.63.124012

DO - 10.1103/PhysRevD.63.124012

M3 - Article

AN - SCOPUS:0034890203

VL - 63

JO - Physical review D: Particles and fields

JF - Physical review D: Particles and fields

SN - 0556-2821

IS - 12

M1 - 124012

ER -