Probing the Properties of Neutron Stars with Type-I X-Ray Bursts

Abstract

The increase in spin frequency as the burning atmospheres of TypeI 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 $3GM/c^2$ for any equation of state and approximately $3.5GM/c^2$ for most physically reasonable equations of state. This constraint arises because the direction of the Coriolis force for radial motion reverses for $R<G/c^2(M+I/R^2)$. 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, 1.6M${}_{\odot }$ versus 1.4M${}_{\odot }$. \

8 pages, 1 figure, submitted to Astrophys. J. Lett

References in corpus (1)

• Spin Down of Pulsations in the Cooling Tail of an X-ray Burst from 4U 1636-53

Cited by in corpus (8)

• R-Modes on Rapidly Rotating, Relativistic Stars: I. Do Type-I Bursts Excite Modes in the Neutron-Star Ocean?
• Surface Modes on Bursting Neutron Stars and X-ray Burst Oscillations
• Dark matter seeding and the kinematics and rotation of neutron stars
• Centrifugally driven relativistic dynamics on curved trajectories
• Hydrostatic Expansion and Spin Changes During Type I X-Ray Bursts
• R-Modes on Rapidly Rotating, Relativistic Stars : II. Blackbody Emission
• The centrifugal force reversal and X-ray bursts
• Inertial Forces as Viewed from the ADM Slicing and their behaviour for Particles in Non-Circular Geodesics