Astronomy and Astrophysics – Astrophysics – High Energy Astrophysical Phenomena
Scientific paper
2011-10-19
Astronomy and Astrophysics
Astrophysics
High Energy Astrophysical Phenomena
8 pages, 6 figures, submitted to ApJ
Scientific paper
A moderately spinning neutron star acquires an oblate shape and a spacetime with a significant quadrupole moment. These two properties affect its apparent surface area for an observer at infinity, as well as the lightcurve arising from a hot spot on its surface. In this paper, we develop a ray-tracing algorithm to calculate the apparent surface areas of moderately spinning neutron stars making use of the Hartle-Thorne metric. This analytic metric allows us to calculate various observables of the neutron star in a way that depends only on its macroscopic properties and not on the details of its equation of state. We use this algorithm to calculate the changes in the apparent surface area, which could play a role in measurements of neutron star radii and, therefore, in constraining their equation of state. We show that whether the spinning neutron star appears larger or smaller than its non-rotating counterpart depends primarily on its equatorial radius. For neutron stars with radii ~10 km, the corrections to the Schwarzschild spacetime cause the apparent surface area to increase with spin frequency. In contrast, for neutron stars with radii ~15 km, the oblateness of the star dominates the spacetime corrections and causes the apparent surface area to decrease with increasing spin frequency. In all cases, the change in the apparent geometric surface area for the range of observed spin frequencies is < 5% and hence only a small source of error in the measurement of neutron star radii.
Baubock Michi
Johannsen Tim
Ozel Feryal
Psaltis Dimitrios
No associations
LandOfFree
A Ray-Tracing Algorithm for Spinning Compact Object Spacetimes with Arbitrary Quadrupole Moments. II. Neutron Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A Ray-Tracing Algorithm for Spinning Compact Object Spacetimes with Arbitrary Quadrupole Moments. II. Neutron Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Ray-Tracing Algorithm for Spinning Compact Object Spacetimes with Arbitrary Quadrupole Moments. II. Neutron Stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-550511