arXiv subjects

Marina Afonina

Publications and source records attributed to Marina Afonina.

4 recordsLinked to original sources

arXiv2026

Population synthesis of low-mass binaries with wind-accreting neutron stars

We perform population synthesis modeling of neutron star binary systems containing a low-mass main-sequence companion underfilling its Roche lobe. About $10^5$ such systems are expected to exist in the Milky Way. In the majority of such systems, NSs are expected to start accreting the stellar wind matter within a few Gyr, resulting in the appearance of a dim X-ray source. The exact value of this fraction mainly depends on the efficiency of the propeller spin-down, properties of the stellar wind, and common envelope efficiency. Mostly, NSs in such systems are formed in electron capture supernovae. Thus, they obtain a low natal kick. Due to this, the center-of-mass velocities of such binaries are low, too. Only in the case of high common envelope efficiency ($α_\mathrm{CE}\gtrsim 3$), a few tens of long-lived high-velocity binaries can be produced in core-collapse supernovae.

astro-ph.HE↗

arXiv2026

Can accreting isolated neutron stars be detected?

We perform population synthesis modeling of isolated neutron stars in the Milky Way over its lifetime. Compared with previous studies, we use more detailed models of the interstellar medium and the magneto-rotational evolution of neutron stars. We demonstrate that presently, the spin-down rate at the propeller stage is the main uncertain factor that influences the number of accreting isolated neutron stars. If the propeller stage duration allows neutron stars to begin accreting matter from the interstellar medium and if the efficiency of accretion is high, then the number of accreting isolated neutron stars in eROSITA data can reach ~a few thousand. Still, uncertainties in spin-down at the propeller stage and in the accretion process can drastically decrease this number. We suggest that future observations of neutron stars in wide low-mass binaries recently discovered by Gaia can clarify these issues.

astro-ph.HE↗

arXiv2025

Low-frequency observations of low-mass binary systems with neutron star candidates

Recently, astrometric and spectroscopic observations resulted in the discovery of several low-mass binaries with invisible components, which are expected to be compact objects. In about two dozen cases, the masses of these components are consistent with neutron stars. We use low-frequency archival data obtained with the Large Phased Array in Pushchino to search for radio emission from five of these systems. For all the systems, we do not detect persistent or periodic emission. In one case (2MASS J1527+3536), we identify a single radio burst with a flux of 13 Jy and a duration of 0.13 s. However, the dispersion measure of the burst does not correspond to an expected value for the source. We discuss several possibilities to explain the properties of this burst.

astro-ph.HE↗

arXiv2025

Evolution of neutron stars in wide eccentric low-mass binary systems

Precise astrometric measurement with Gaia satellite resulted in the discovery of tens of wide binary systems consisting of a Sun-like star and an invisible component. The latter can be a white dwarf, a neutron star, or a black hole. In this paper, we model magneto-rotational evolution of neutron stars in wide low-mass binaries accounting for the orbital eccentricity. We aim to calculate when neutron stars in such systems can start to accrete matter from the stellar wind of the companion. We show that the transition from the ejector to the propeller stage occurs earlier in more eccentric systems, thus increasing the time that neutron stars can spend accreting matter. Our calculations show that in the case of efficient spin-down at the propeller stage, a neutron star in an eccentric orbit with $e\gtrsim0.6$ and a standard magnetic field $B=10^{12}$ G can start accreting within a few Gyr. For neutron stars with $B=10^{13}$ G the onset of accretion occurs earlier regardless of the orbital eccentricity. Otherwise, with a lower spin-down rate, such a neutron star will remain at the propeller stage for most of its life.

astro-ph.HE↗