Probing the Properties of Neutron Stars with Type I X-Ray Bursts
Abstract
The increase in spin frequency as the burning atmospheres of type I X-ray bursts cool provides a strong constraint on the radius of the underlying neutron star. If the change in spin frequency is due to a change in the thickness of the atmosphere, the radius of the star must exceed 3GM/c2 for any equation of state and approximately 3.5GM/c2 for most physically reasonable equations of state. This constraint arises because the direction of the Coriolis force for radial motion reverses for R<G/c2(M+I/R2). Furthermore, the marked change in the magnitude of the Coriolis force near compact stars provides a straightforward explanation for why the frequency of the quickly rotating bursters shifts by the same amount as the slow rotators: they are slightly more massive, 1.6 Msolar versus 1.4 Msolar.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2000
- DOI:
- 10.1086/312912
- arXiv:
- arXiv:astro-ph/0004305
- Bibcode:
- 2000ApJ...542L..45H
- Keywords:
-
- Equation of State;
- Relativity;
- Stars: Neutron;
- X-Rays: Bursts;
- Astrophysics
- E-Print:
- 8 pages, 1 figure, submitted to Astrophys. J. Lett