Why most neutron star low-mass X-ray binaries accrete transiently: an evolutionary study of transient and persistent phases
Abstract
A neutron star (NS) low-mass X-ray binary (LMXB), in which an NS accretes matter from a low-mass donor star, is an ideal source for probing some fundamental aspects of physics and astronomy, such as strong gravity, superdense matter, and the accretion-ejection processes. However, to reliably achieve these goals, one must adequately understand NS LMXBs, including why some accrete persistently and others transiently. Focused models, such as those based on a thermal-viscous instability in the accretion disk, are considered to explain transient accretion. However, broader perspectives, including which LMXB parameter values and phases cause transients and why there are more transients than persistents, remain poorly understood. Here, our computation of the long-term evolution of NS LMXBs addresses these questions, providing insight into LMXB parameters and phases, naturally producing more transients than persistents, and being partially consistent with the known properties of observed sources. For example, we typically find a greater fraction of persistent phase at lower orbital periods from the LMXB evolution computation, which is somewhat consistent with observations. However, a lack of full consistency calls for improving the aforementioned focused models, and our computations provide a new way to discriminate among these models.
Related
- UOCS. XVI. Census of post mass-transfer binaries across various evolutionary phases in M67
- Neutron Star--Primordial Black Hole Binaries: Dynamical Tides, Resonance Locking, and Gravitational Waves
- A semicoherent resampling method for long-transient gravitational wave searches with applications to subsolar-mass primordial black-hole binaries
- Population synthesis of low-mass binaries with wind-accreting neutron stars
- A re-examination of neutron star cooling in transient sources. No shallow heating required: The role of thermonuclear heating leakage
BibTeX
@misc{tripathi2026most,
title = {{Why most neutron star low-mass X-ray binaries accrete transiently: an evolutionary study of transient and persistent phases}},
author = {Divyansh Tripathi and Sudip Bhattacharyya and Pulkit Ojha},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.21324},
eprint = {2609.21324},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.21324},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Why most neutron star low-mass X-ray binaries accrete transiently: an evolutionary study of transient and persistent phases
AU - Divyansh Tripathi
AU - Sudip Bhattacharyya
AU - Pulkit Ojha
PY - 2026
DA - 2026/10/08
PB - arXiv
DO - 10.48550/arxiv.2609.21324
UR - https://arxiv.org/abs/2609.21324
AB - A neutron star (NS) low-mass X-ray binary (LMXB), in which an NS accretes matter from a low-mass donor star, is an ideal source for probing some fundamental aspects of physics and astronomy, such as strong gravity, superdense matter, and the accretion-ejection processes. However, to reliably achieve these goals, one must adequately understand NS LMXBs, including why some accrete persistently and others transiently. Focused models, such as those based on a thermal-viscous instability in the accretion disk, are considered to explain transient accretion. However, broader perspectives, including which LMXB parameter values and phases cause transients and why there are more transients than persistents, remain poorly understood. Here, our computation of the long-term evolution of NS LMXBs addresses these questions, providing insight into LMXB parameters and phases, naturally producing more transients than persistents, and being partially consistent with the known properties of observed sources. For example, we typically find a greater fraction of persistent phase at lower orbital periods from the LMXB evolution computation, which is somewhat consistent with observations. However, a lack of full consistency calls for improving the aforementioned focused models, and our computations provide a new way to discriminate among these models.
ER -