Indications of non-conservative mass-transfer in AMXPs

Abstract

Context. Since the discovery of the first Accreting Millisecond X-ray Pulsar SAX J1808.4-3658 in 1998, the family of these sources kept growing on. Currently, it counts 22 members. All AMXPs are transients with usually very long quiescence periods, implying that mass accretion rate in these systems is quite low and not constant. Moreover, for at least three sources, a non-conservative evolution was also proposed. Aims. Our purpose is to study the long term averaged mass-accretion rates in all the Accreting Millisecond X-ray Pulsars discovered so far, to investigate a non-conservative mass-transfer scenario. Methods. We calculated the expected mass-transfer rate under the hypothesis of a conservative evolution based on their orbital periods and on the (minimum) mass of the secondary (as derived from the mass function), driven by gravitational radiation and/or magnetic braking. Using this theoretical mass-transfer, we determined the expected accretion luminosity of the systems. Thus, we achieved the lower limit to the distance of the sources by comparing the computed theoretical luminosity and the observed flux averaged over a time period of 20 years. Then, the lower limit to the distance of the sources has been compared to the value of the distance reported in literature to evaluate how reasonable is the hypothesis of a conservative mass-transfer. Results. Based on a sample of 18 sources, we found strong evidences of a non-conservative mass-transfer for five sources, for which the estimated distance lower limits are higher than their known distances. We also report hints for mass outflows in other six sources. The discrepancy can be fixed under the hypothesis of a non-conservative mass-transfer in which a fraction of the mass transferred onto the compact object is swept away from the system, likely due to the (rotating magnetic dipole) radiation pressure of the pulsar.

12 pages, 2 figures, accepted for publication in A&A

References in corpus (25)

• The Gaia mission
• A Radio Pulsar/X-ray Binary Link
• INTEGRAL observations of the cosmic X-ray background in the 5-100 keV range via occultation by the Earth
• Near-IR properties of 24 Globular Clusters in the Galactic Bulge
• Discovery of coherent millisecond X-ray pulsations in Aql X-1
• Interstellar Extinction Law toward the Galactic Center II: V, J, H, and Ks Bands
• Discovery of PSR J1227-4853: A transition from a low-mass X-ray binary to a redback millisecond pulsar
• Broad relativistic iron emission line observed in SAX J1808.4-3658
• Intermittent millisecond X-ray pulsations from the neutron-star X-ray transient SAX J1748.9-2021 in the globular cluster NGC 6440
• Orbital Evolution of an Accreting Millisecond Pulsar: Witnessing the Banquet of a Hidden Black Widow?
• Timing of the Accreting Millisecond Pulsar XTE J1814-338
• Low Mass X-ray Binaries: The Effects of the Magnetic Braking Prescription
• The nature of very faint X-ray binaries; hints from light curves
• New ephemeris of the ADC source 2A 1822-371: a stable orbital-period derivative over 30 years
• Timing of the 2008 Outburst of SAX J1808.4-3658 with XMM-Newton: A Stable Orbital Period Derivative over Ten Years
• The donor of Aquila X-1 revealed by high angular resolution near-infrared spectroscopy
• On the timing properties of SAX J1808.4-3658 during its 2015 outburst
• X-ray Reflection and An Exceptionally Long Thermonuclear Helium Burst from IGR J17062-6143
• Spin up and phase fluctuations in the timing of the accreting millisecond pulsar XTE J1807-294
• Discovery of a new accreting millisecond X-ray pulsar in the globular cluster NGC 2808
• The 2015 outburst of the accretion-powered pulsar IGR J00291+5934: INTEGRAL and Swift observations
• Spectral and timing properties of the accreting X-ray millisecond pulsar IGR J17498-2921
• Timing and spectral properties of the accreting millisecond pulsar SWIFT J1756.9-2508
• The 2015 outburst of the accreting millisecond pulsar IGR J17511-3057 as seen by INTEGRAL, Swift and XMM-Newton
• Evidence of a non-conservative mass transfer for XTE J0929-314

Cited by in corpus (6)

• Binary Stars in the New Millennium
• NICER Discovery of Millisecond X-ray Pulsations and an Ultracompact Orbit in IGR J17494-3030
• A broadband look of the Accreting Millisecond X-ray Pulsar SAX J1748.9-2021 using AstroSat and XMM-Newton
• Outflows and spectral evolution in the eclipsing AMXP SWIFT J1749.4-2807 with NICER, XMM-Newton and NuSTAR
• AstroSat and NuSTAR observations of XTE J1739-285 during the 2019-2020 outburst
• A tentative 114-minute orbital period challenges the ultra-compact nature of the X-ray binary 4U 1812-12