The Different Fates of a Low-Mass X-ray Binary. I: Conservative Mass Transfer

Abstract

We study the evolution of a low mass x-ray binary coupling a binary stellar evolution code with a general relativistic code that describes the behavior of the neutron star. We assume the neutron star to be low--magnetized (B~10^8 G). In the systems investigated in this paper, our computations show that during the binary evolution the companion transfers as much as 1 solar mass to the neutron star, with an accretion rate of 10^-9 solar masses/yr. This is sufficient to keep the inner rim of the accretion disc in contact with the neutron star surface, thus preventing the onset of a propeller phase capable of ejecting a significant fraction of the matter transferred by the companion. We find that, for neutron stars governed by equations of state from soft up to moderately stiff, an accretion induced collapse to a black hole is almost unavoidable. The collapse to a black hole can occur either during the accretion phase or after the end of the mass transfer when the neutron star is left in a supramassive sequence. In this last case the collapse is driven by energy losses of the fast spinning radio pulsar. For extremely supramassive neutron stars these energy losses cause a spin up. As a consequence the pulsar will have a much shorter lifetime than that of a canonical radio pulsar. This behavior depends on the equation of state for ultra-dense matter and therefore could be used to constrain the internal structure of the neutron star. If the r-modes of the neutron star are excited during the accretion process, the gravitational waves emisson limits the maximum spin attainable by a NS to roughly 2 ms. In this case the collapse during the accretion phase is even more common since the maximum mass achievable before the collapse to a black hole during accretion is smaller due to the limited spin frequency.

arXiv comment11 pages, 5 figures. Accepted for publication in MNRAS

References in corpus (19)

• A new class of unstable modes of rotating relativistic stars
• Neutron Star Mass Measurements. I. Radio Pulsars
• Evolutionary Binary Sequences for Low- and Intermediate-Mass X-ray Binaries
• Comparing Models of Rapidly Rotating Relativistic Stars Constructed by Two Numerical Methods
• Gravitational Radiation and Rotation of Accreting Neutron Stars
• The Neutron Stars of Soft X-Ray Transients
• On the relevance of the r-mode instability for accreting neutron stars and white dwarfs
• Discovery of a Second Millisecond Accreting Pulsar: XTE J1751-305
• Discovery of a High-Latitude Accreting Millisecond Pulsar in an Ultracompact Binary
• The Galactic Population of Low- and Intermediate-Mass X-ray Binaries
• Runaway Heating By R-modes of Neutron Stars in Low Mass X-ray Binaries
• Crust-core coupling and r-mode damping in neutron stars: a toy model
• Where May Ultra-Fast Rotating Neutron Stars Be Hidden?
• The broad-band power spectrum of SAX J1808.4-3658
• Rotating Stars in Relativity
• Neutron stars with submillisecond periods: a population of high mass objects?
• On a Theoretical Interpretation of the Period Gap in Binary Millisecond Pulsars
• Lower Limit on Radius as a Function of Mass for Neutron Stars
• Constraints on the Steady-State R-mode Amplitude in Neutron Star Transients

Cited by in corpus (6)

• Electromagnetic Fields in the Exterior of an Oscillating Relativistic Star -- I. General Expressions and application to a rotating magnetic dipole
• Evolutionary paths of binaries with a neutron star. I. The case of SAX J1808.4-3658
• Compression of matter in the center of accreting neutron stars
• XMM-Newton observations of IGR J00291+5934: signs of a thermal spectral component during quiescence
• Radio-ejection and bump-related orbital period gap of millisecond binary pulsars
• The role of General Relativity in the evolution of Low Mass X-ray Binaries