The Optical Light Curves of XTE J2123−058. III. The Mass of the Binary Components and the Structure of the Quiescent Accretion Disk

Shahbaz, T.; Zurita, C.; Casares, J.; Dubus, G.; Charles, P. A.; Wagner, R. M.; Ryan, Erin L.

doi:10.1086/346001

Cited by 34 publications

(50 citation statements)

References 46 publications

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“…7) gives a time of maximum To = 2456018.47(2) and a full amplitude ∆U = 0.32(4). While the amplitude of the modulation is similar to those observed in other LMXBs, the light curve is not double-humped as it would be expected from ellipsoidal variations of the secondary star (Shahbaz et al 2003). Single humped light curves with a minimum at inferior conjunction of the secondary star instead indicate that the donor irradiation is an important source of variability as also observed during low states in the MSP binaries SAX J1808.42-3658 (Homer et al 2001), PSR J102347+0038 (Thorstensen & Armstrong 2005) or PSR J2215+5135 (Breton et al 2013;Schroeder & Halpern 2014).…”

Section: The Variability During the Persistent Statesupporting

confidence: 76%

Unveiling the redback nature of the low-mass X-ray binary XSS J1227.0−4859 through optical observations★

Martino

Casares

Mason

et al. 2014

Monthly Notices of the Royal Astronomical Society

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The peculiar low mass X-ray binary XSS J12270-4859, associated with the Fermi/LAT source 2FGL J1227.7-4853, was in a X-ray, gamma-ray and optical low-luminosity persistent state for about a decade until the end of 2012, when it has entered into the dimmest state ever observed. The nature of the compact object has been controversial until the detection of a 1.69ms radio pulsar early 2014. We present optical spectroscopy and optical/near-IR photometry during the previous brighter and in the recent faint states. We determine the first spectroscopic orbital ephemeris and an accurate orbital period of 6.91246(5) h. We infer a mid G-type donor star and a distance d= 1.8-2.0 kpc. The donor spectral type changes from G5 V to F5 V between inferior and superior conjunction, a signature of strong irradiation effects. We infer a binary inclination 45 o i 65 o and a highly undermassive donor, M 2 ∼ 0.06 − 0.12 M ⊙ for a neutron star mass in the range 1.4-3 M ⊙ . Thus this binary joins as the seventh member the group of "redbacks". In the high state, the emission lines reveal the presence of an accretion disc. They tend to vanish at the donor star superior conjunction, where also flares are preferentially observed together with the occurrence of random dips. This behaviour could be related to the propeller mechanism of the neutron star recently proposed to be acting in this system during the high state. In the low state, the emission lines are absent at all orbital phases indicating that accretion has completely switched-off and that XSS J12270-4859 has transited from an accretion-powered to a rotation-powered phase.

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Section: The Variability During the Persistent Statesupporting

confidence: 76%

Unveiling the redback nature of the low-mass X-ray binary XSS J1227.0−4859 through optical observations★

Martino

Casares

Mason

et al. 2014

Monthly Notices of the Royal Astronomical Society

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“…see Shahbaz et al 2003Shahbaz et al , 2004. to fit and interpret the photometric light curves and the Hα absorption-line radial velocity curve of 3FGL J0212.1+5320 presented in Linares et al (2016).…”

Section: The X-ray Binary Modelmentioning

confidence: 99%

Properties of the redback millisecond pulsar binary 3FGL J0212.1+5320

Shahbaz

Linares

Breton

2017

Monthly Notices of the Royal Astronomical Society

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Linares et al. (2016) obtained quasi-simultaneous g , r and i -band light curves and an absorption line radial velocity curve of the secondary star in the redback system 3FGL J0212.1+5320. The light curves showed two maxima and minima primarily due to the secondary star's ellipsoidal modulation, but with unequal maxima and minima. We fit these light curves and radial velocities with our X-ray binary model including either a dark solartype star spot or a hot spot due to off-centre heating from an intrabinary shock, to account for the unequal maxima. Both models give a radial velocity semi-ampltiude and rotational broadening that agree with the observations. The observed secondary star's effective temperature is best matched with the value obtained using the hot spot model, which gives a neutron star and secondary star mass of M 1 =1.85

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“…To interpret the I-band light curve and the absorption-and emission-line radial velocity Mass ratio Inclination Scaled WD radius curves we used the xrbcurve model described in Shahbaz et al (2003), which has successfully been used to model the light curves and radial velocity curves of neutron star and black hole X-ray binaries (Shahbaz et al 2004). Briefly, the model includes a Roche-lobe filling secondary star, the effects of UV/X-ray heating of the secondary star by a source of high energy photons from a compact object, an accretion disc and mutual eclipses of the disc and star.…”

Section: Simultaneous Radial Velocity and Ellipsoidal Modulation Modementioning

confidence: 99%

“…The irradiating flux can strongly alter the distribution of temperature across the face of the secondary star and thus the observed optical light curves and radial velocities. For the light curves, the heating of the secondary star is computed in the same way as described in Shahbaz et al (2003), who calculate the increase in unperturbed local effective temperature due to the irradiating external source. Substantial heating of the secondary star also shifts the effective centre of the secondary, weighted by the strength of the absorption and emission lines, from the centre of mass of the star.…”

Section: Simultaneous Radial Velocity and Ellipsoidal Modulation Modementioning

confidence: 99%

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Dynamical masses of a nova-like variable on the edge of the period gap

Rodríguez‐Gil

Shahbaz

Marsh

et al. 2015

Mon. Not. R. Astron. Soc.

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We present the first dynamical determination of the binary parameters of an eclipsing SW Sextantis star in the 3-4 hour orbital period range during a low state. We obtained time-resolved optical spectroscopy and photometry of HS 0220+0603 during its 2004-2005 low brightness state, as revealed in the combined SMARTS, IAC80 and M1 Group long-term optical light curve.The optical spectra taken during primary eclipse reveal a secondary star spectral type of M5.5±0.5 as derived from molecular band-head indices. The spectra also provide the first detection of a DAB white dwarf in a cataclysmic variable. By modelling its optical spectrum we estimate a white dwarf temperature of 30 000 ± 5 000 K.By combining the results of modelling the white dwarf eclipse from ULTRA-CAM light curves with those obtained by simultaneously fitting the emission-and absorption-line radial velocity curves and I-band ellipsoidal light curves, we measure the stellar masses to be M 1 = 0.87 ± 0.09 M and M 2 = 0.47 ± 0.05 M for the white dwarf and the M dwarf, respectively, and an inclination of the orbital plane of i ≈ 79 o . A radius of 0.0103 ± 0.0007 R is obtained for the white dwarf. The secondary star in HS 0220+0603 is likely too cool and undersized for its mass.

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The Optical Light Curves of XTE J2123−058. III. The Mass of the Binary Components and the Structure of the Quiescent Accretion Disk

Cited by 34 publications

References 46 publications

Unveiling the redback nature of the low-mass X-ray binary XSS J1227.0−4859 through optical observations★

Unveiling the redback nature of the low-mass X-ray binary XSS J1227.0−4859 through optical observations★

Properties of the redback millisecond pulsar binary 3FGL J0212.1+5320

Dynamical masses of a nova-like variable on the edge of the period gap

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