#### Preview

We calculate light curves produced by a hotspot of a rapidly rotating neutron star, assuming that the spot is perturbed by a core r mode, which is destabilized by emitting gravitational waves. To calculate light curves, we take account of relativistic effects, such as the Doppler boost due to the rapid rotation and light bending, assuming the Schwarzschild metric around the neutron star. We assume that the core r modes penetrate to the surface fluid ocean to have sufficiently large amplitudes to disturb the spot. For an *l*′=*m* core r mode, the oscillation frequency ω≈ 2*m*Ω/[*l*′ (*l*′+ 1)] defined in the corotating frame of the star will be detected by a distant observer, where *l*′ and *m* are, respectively, the spherical harmonic degree and the azimuthal wavenumber of the mode, and Ω is the spin frequency of the star. In a linear theory of oscillation, using a parameter *A*, we parametrize the mode amplitudes, such that max (|ξ_{θ}|, |ξ_{φ}|)/*R*=*A* at the surface, where ξ_{θ} and ξ_{φ} are, respectively, the θ and φ components of the displacement vector of the mode and *R* is the radius of the star. For the *l*′=*m*= 2 r mode with ω= 2Ω/3, we find that the fractional Fourier amplitudes at ω= 2Ω/3 in light curves depend on the angular distance θ_{s} of the spot centre measured from the rotation axis and become comparable to or even larger than *A*∼ 0.001 for small values of θ_{s}.

*Keywords: *
stars: magnetic field;
stars: neutron;
stars: oscillations;
stars: rotation

*Journal Article.*
*4983 words.*
*Illustrated.*

*Subjects: *
Astronomy and Astrophysics

Go to Oxford Journals » abstract

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.