Evidence of a non-conservative mass transfer for XTE J0929-314

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Abstract

Context. In 1998 the first accreting millisecond pulsar, SAX J1808.4-3658, was discovered and to date 18 systems showing coherent, high frequency (>100 Hz) pulsations in low-mass X-ray binaries are known. Since their discovery, this class of sources has shown interesting and sometimes puzzling behaviours. In particular, apart from a few exceptions, they are all transient with very long X-ray quiescent periods implying a quite low averaged mass accretion rate onto the neutron star. Among these sources, XTE J0929-314 has been detected in outburst just once in about 15 years of continuous monitoring of the X-ray sky. Aims. We aim to demonstrate that a conservative mass transfer in this system will result in an X-ray luminosity that is higher than the observed, long-Term averaged X-ray luminosity. Methods. Under the hypothesis of a conservative mass transfer driven by gravitational radiation, as expected for this system given the short orbital period of about 43.6 min and the low-mass of the companion implied by the mass function derived from timing techniques, we calculate the expected mass transfer rate in this system and predict the long-Term averaged X-ray luminosity. This is compared with the averaged, over 15 years, X-ray flux observed from the system, and a lower limit of the distance to the source is inferred. Results. This distance is shown to be >7.4 kpc in the direction of the Galactic anticentre, implying a large height, >1.8 kpc, of the source with respect to the Galactic plane, placing the source in an empty region of the Galaxy. We suggest that the inferred value of the distance is unlikely. Conclusions. This problem can be solved if we hypothesize that the source is undergoing a non-conservative mass transfer, in which most of the mass transferred from the companion star is ejected from the system, probably because of the (rotating magnetic dipole) radiation pressure of the pulsar. If confirmed by future observations, this may be another piece of evidence that accreting millisecond pulsars experience a non-conservative mass transfer.
Lingua originaleEnglish
pagine (da-a)A137-
Numero di pagine6
RivistaASTRONOMY & ASTROPHYSICS
Volume603
Stato di pubblicazionePublished - 2017

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mass transfer
pulsars
x rays
luminosity
companion stars
radiation pressure
magnetic dipoles
outburst
gravitational waves
neutron stars
sky
accretion
time measurement
galaxies
orbitals
monitoring

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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@article{1f43f10b6ec84bfebd776fff7123f695,
title = "Evidence of a non-conservative mass transfer for XTE J0929-314",
abstract = "Context. In 1998 the first accreting millisecond pulsar, SAX J1808.4-3658, was discovered and to date 18 systems showing coherent, high frequency (>100 Hz) pulsations in low-mass X-ray binaries are known. Since their discovery, this class of sources has shown interesting and sometimes puzzling behaviours. In particular, apart from a few exceptions, they are all transient with very long X-ray quiescent periods implying a quite low averaged mass accretion rate onto the neutron star. Among these sources, XTE J0929-314 has been detected in outburst just once in about 15 years of continuous monitoring of the X-ray sky. Aims. We aim to demonstrate that a conservative mass transfer in this system will result in an X-ray luminosity that is higher than the observed, long-Term averaged X-ray luminosity. Methods. Under the hypothesis of a conservative mass transfer driven by gravitational radiation, as expected for this system given the short orbital period of about 43.6 min and the low-mass of the companion implied by the mass function derived from timing techniques, we calculate the expected mass transfer rate in this system and predict the long-Term averaged X-ray luminosity. This is compared with the averaged, over 15 years, X-ray flux observed from the system, and a lower limit of the distance to the source is inferred. Results. This distance is shown to be >7.4 kpc in the direction of the Galactic anticentre, implying a large height, >1.8 kpc, of the source with respect to the Galactic plane, placing the source in an empty region of the Galaxy. We suggest that the inferred value of the distance is unlikely. Conclusions. This problem can be solved if we hypothesize that the source is undergoing a non-conservative mass transfer, in which most of the mass transferred from the companion star is ejected from the system, probably because of the (rotating magnetic dipole) radiation pressure of the pulsar. If confirmed by future observations, this may be another piece of evidence that accreting millisecond pulsars experience a non-conservative mass transfer.",
author = "Rosario Iaria and Gambino, {Angelo Francesco} and {Di Salvo}, Tiziana and Alessio Marino and Marco Matranga and Riggio and Sanna and Burderi",
year = "2017",
language = "English",
volume = "603",
pages = "A137--",
journal = "ASTRONOMY & ASTROPHYSICS",
issn = "0004-6361",

}

TY - JOUR

T1 - Evidence of a non-conservative mass transfer for XTE J0929-314

AU - Iaria, Rosario

AU - Gambino, Angelo Francesco

AU - Di Salvo, Tiziana

AU - Marino, Alessio

AU - Matranga, Marco

AU - Riggio, null

AU - Sanna, null

AU - Burderi, null

PY - 2017

Y1 - 2017

N2 - Context. In 1998 the first accreting millisecond pulsar, SAX J1808.4-3658, was discovered and to date 18 systems showing coherent, high frequency (>100 Hz) pulsations in low-mass X-ray binaries are known. Since their discovery, this class of sources has shown interesting and sometimes puzzling behaviours. In particular, apart from a few exceptions, they are all transient with very long X-ray quiescent periods implying a quite low averaged mass accretion rate onto the neutron star. Among these sources, XTE J0929-314 has been detected in outburst just once in about 15 years of continuous monitoring of the X-ray sky. Aims. We aim to demonstrate that a conservative mass transfer in this system will result in an X-ray luminosity that is higher than the observed, long-Term averaged X-ray luminosity. Methods. Under the hypothesis of a conservative mass transfer driven by gravitational radiation, as expected for this system given the short orbital period of about 43.6 min and the low-mass of the companion implied by the mass function derived from timing techniques, we calculate the expected mass transfer rate in this system and predict the long-Term averaged X-ray luminosity. This is compared with the averaged, over 15 years, X-ray flux observed from the system, and a lower limit of the distance to the source is inferred. Results. This distance is shown to be >7.4 kpc in the direction of the Galactic anticentre, implying a large height, >1.8 kpc, of the source with respect to the Galactic plane, placing the source in an empty region of the Galaxy. We suggest that the inferred value of the distance is unlikely. Conclusions. This problem can be solved if we hypothesize that the source is undergoing a non-conservative mass transfer, in which most of the mass transferred from the companion star is ejected from the system, probably because of the (rotating magnetic dipole) radiation pressure of the pulsar. If confirmed by future observations, this may be another piece of evidence that accreting millisecond pulsars experience a non-conservative mass transfer.

AB - Context. In 1998 the first accreting millisecond pulsar, SAX J1808.4-3658, was discovered and to date 18 systems showing coherent, high frequency (>100 Hz) pulsations in low-mass X-ray binaries are known. Since their discovery, this class of sources has shown interesting and sometimes puzzling behaviours. In particular, apart from a few exceptions, they are all transient with very long X-ray quiescent periods implying a quite low averaged mass accretion rate onto the neutron star. Among these sources, XTE J0929-314 has been detected in outburst just once in about 15 years of continuous monitoring of the X-ray sky. Aims. We aim to demonstrate that a conservative mass transfer in this system will result in an X-ray luminosity that is higher than the observed, long-Term averaged X-ray luminosity. Methods. Under the hypothesis of a conservative mass transfer driven by gravitational radiation, as expected for this system given the short orbital period of about 43.6 min and the low-mass of the companion implied by the mass function derived from timing techniques, we calculate the expected mass transfer rate in this system and predict the long-Term averaged X-ray luminosity. This is compared with the averaged, over 15 years, X-ray flux observed from the system, and a lower limit of the distance to the source is inferred. Results. This distance is shown to be >7.4 kpc in the direction of the Galactic anticentre, implying a large height, >1.8 kpc, of the source with respect to the Galactic plane, placing the source in an empty region of the Galaxy. We suggest that the inferred value of the distance is unlikely. Conclusions. This problem can be solved if we hypothesize that the source is undergoing a non-conservative mass transfer, in which most of the mass transferred from the companion star is ejected from the system, probably because of the (rotating magnetic dipole) radiation pressure of the pulsar. If confirmed by future observations, this may be another piece of evidence that accreting millisecond pulsars experience a non-conservative mass transfer.

UR - http://hdl.handle.net/10447/239278

UR - http://www.edpsciences.org/journal/index.cfm?edpsname=aa

M3 - Article

VL - 603

SP - A137-

JO - ASTRONOMY & ASTROPHYSICS

JF - ASTRONOMY & ASTROPHYSICS

SN - 0004-6361

ER -