The X-ray binary 2S0114+650=LSI+65 010

Koenigsberger, Gloria; Георгиев, Л.; Moreno, E.; Richer, M. G.; Toledano, O.; Canalizo, Gabriela; Arrieta, A.

doi:10.1051/0004-6361:20065305

Cited by 41 publications

(63 citation statements)

References 22 publications

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“…In this approximation, the buoyancy force is not taken into account. Finally, we note that the results in this paper are obtained using a polytropic index n = 1.5, corresponding to a rigorous convective envelope, instead of n = 1 as was used previously (Moreno et al 2005;Koenigsberger et al 2006), although the difference between the results obtained for these two values of n is not significant. Moreno et al (2005) extended the model to include the computation of the photospheric absorption lines that would be produced by the perturbed stellar surface.…”

Section: Introductionmentioning

confidence: 90%

Tides in asynchronous binary systems

Toledano

Moreno²,

Koenigsberger

et al. 2006

A&A

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Context. Stellar oscillations are excited in non-synchronously rotating stars in binary systems due to the tidal forces. Tangential components of the tides can drive a shear flow which behaves as a differentially forced rotating structure in a stratified outer medium. Aims. The aims of this paper are to show that our single-layer approximation for the calculation of the forced oscillations yields results that are consistent with the predictions for the synchronization timescales in circular orbits, τ sync ∼ a 6 , thus providing a simplified means of computing the energy dissipation rates,Ė. Furthermore, by calibrating our model results to fit the relationship between synchronization timescales and orbital separation, we are able to constrain the value of the kinematical viscosity parameter, ν. Methods. We compute the values ofĖ for a set of 5 M + 4 M model binary systems with different orbital separations, a, and use these to estimate the synchronization timescales. Results. The resulting τ synch vs. a relation is comparable to that of Zahn (1977, A&A, 57, 383) for convective envelopes, providing a calibration method for the values of ν. For the 4 + 5 M binary modeled in this paper, ν is in the range 0.0015-0.0043 R 2 /day for orbital periods in the range 2.5-25 d. In addition,Ė is found to decrease by ∼2 orders of magnitude as synchronization is approached, implying that binary systems may approach synchronization relatively quickly but that it takes a much longer timescale to actually attain this condition. Conclusions. The relevance of these results is threefold: 1) our model allows an estimate for the numerical value of ν under arbitrary conditions in the binary system; 2) it can be used to calculate the energy dissipation rates throughout the orbital cycle for any value of eccentricity and stellar rotational velocity; and 3) it provides values of the tangential component of the velocity perturbation at any time throughout the orbit and predicts the location on the stellar surface where the largest shear instabilities may be occurring. We suggest that one of the possible implication of the asymmetric distribution ofĖ over the stellar surface is the generation of localized regions of enhanced surface activity.

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Section: Introductionmentioning

confidence: 90%

Tides in asynchronous binary systems

Toledano

Moreno²,

Koenigsberger

et al. 2006

A&A

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“…These authors also found temporary quasi-periodic oscillations with a timescale of ∼2 h which they attribute to alternating high and low density regions within GP Vel's stellar wind. A similarly structured wind has been suggested to exist in the Be/X-ray binary system 2S0114+650 and to possibly be produced by tidally induced pulsations (Koenigsberger et al 2006). …”

Section: Dependence On Layer Depthmentioning

confidence: 97%

Tidal effects on the radial velocity curve of HD 77581 (Vela X-1)

Koenigsberger¹,

Moreno²,

Harrington³

2012

A&A

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Context. The mass of the neutron star in Vela X-1 has been found to be larger than the canonical 1.5 M . This result relies on the assumption that the amplitude of the optical component's measured radial velocity curve is not seriously affected by the interactions in the system. Aims. Our aim is to explore the effect on the radial velocity curve caused by surface motions excited by tidal interactions. Methods. We use a calculation from first principles that involves solving the equations of motion of a Lagrangian grid of surface elements. The velocities on the visible surface of the star are projected along the line-of-sight to the observer to obtain the Doppler shifts which are applied to the local line-profiles, which are then combined to obtain the absorption-line profile in the observer's reference frame. The centroid of the line-profiles for different orbital phases is then measured and a simulated RV curve constructed. Models are run for the "standard" (v sin i = 116 km s −1 ) and "slow" (56 km s −1 ) supergiant rotation velocities. Results. The surface velocity field is complex and includes fast, small-spatial scale structures. It leads to strong variability in the photospheric line profiles which, in turn, causes significant deviations from a Keplerian RV curve. The peak-to-peak amplitudes of model RV curves are in all cases larger than the amplitude of the orbital motion. Keplerian fits to RV curves obtained with the "standard" rotation velocity imply m ns ≥ 1.7 M . However, a similar analysis of the "slow" rotational velocity models allows for m ns ∼ 1.5 M . Thus, the stellar rotation plays an important role in determining the characteristics of the perturbed RV curve. Conclusions. Given the observational uncertainty in GP Vel's projected rotation velocity and the strong perturbations seen in the published and the model RV curves, we are unable to rule out a small (∼1.5 M ) mass for the neutron star companion.

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“…In the Milky Way, two very long period X-ray pulsars with periods >1000 s are known, both of them Be-HMXBs: SAX J2239.3+6116 at P = 1247 s (in't Zand et al 2001), SAX J0146.9+6121 at P = 1412 s (Hellier 1994). The longest X-ray period of all belongs to 2S0114+650 at P =10,008 s which has a B1 supergiant optical counterpart, although it is uncertain whether its X-ray period is the NS spin period or a periodic variation in the accretion rate, driven by tidal modulation of the stellar wind (Koenigsberger et al 2006). X-ray pulsars are the product of close-binary systems containing a pair of massive stars.…”

Section: Pulsars With Very Long Periodsmentioning

confidence: 99%

Exploring the Small Magellanic Cloud to the Faintest X-Ray Fluxes: Source Catalog, Timing, and Spectral Analysis

Laycock

Zezas

Hong

et al. 2010

ApJ

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We present the results of a pair of 100 ks Chandra observations in the Small Magellanic Cloud (SMC) to survey high-mass X-ray binaries (HMXBs), stars, and low-mass X-ray binaries (LMXBs)/cataclysmic variables down to L x = 4.3 × 10 32 erg s −1 . The two SMC Deep Fields (DFs) are located in the most active star-forming region of the bar, with Deep Field-1 positioned at the most pulsar-rich location identified from previous surveys. Two new pulsars were discovered in the outburst: CXOU J004929.7-731058 (P = 892 s), CXOU J005252.2-721715 (P = 326 s), and three new HMXB candidates were identified. Of the 15 Be-pulsars now known in the field, 13 were detected, with pulsations seen in 9 of them. Ephemerides demonstrate that 6 of the 10 pulsars known to exhibit regular outbursts were seen outside their periastron phase, and quiescent X-ray emission at L X = 10 33 -10 34 erg s −1 is shown to be common. Comparison with ROSAT, ASCA, and XMM-Newton catalogs resulted in positive identification of several previously ambiguous sources. Bright optical counterparts exist for 40 of the X-ray sources, of which 33 are consistent with early-type stars (M V < −2, B −V < 0.2), and are the subject of a companion paper. The results point to an underlying HMXB population density up to double that of active systems. The full catalog of 394 point sources is presented along with detailed analyses of timing and spectral properties.

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The X-ray binary 2S0114+650=LSI+65 010

Cited by 41 publications

References 22 publications

Tides in asynchronous binary systems

Tides in asynchronous binary systems

Tidal effects on the radial velocity curve of HD 77581 (Vela X-1)

Exploring the Small Magellanic Cloud to the Faintest X-Ray Fluxes: Source Catalog, Timing, and Spectral Analysis

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