Phase-dependent X-ray observations of the <i>β</i> Lyrae system

Ignace, Richard; Oskinova, L. M.; Waldron, W. L.; Hoffman, Jennifer L.; Hamann, W. R.

doi:10.1051/0004-6361:20078871

Cited by 12 publications

(10 citation statements)

References 23 publications

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“…With our results providing support for mass transfer in the O8 III + o9 v binary, multi-wavelength observations may reveal a far more complicated picture for QZ Car (e.g. β Lyrae; Ignace et al 2008).…”

Section: Discussionsupporting

confidence: 55%

X-Ray Emission From the Double-Binary Ob-Star System Qz Car (Hd 93206)

Parkin¹,

Broos²,

Townsley³

et al. 2011

ApJS

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X-ray observations of the double-binary OB-star system QZ Car (HD 93206) obtained with the Chandra X-ray Observatory over a period of roughly 2 years are presented. The orbit of systems A (O9.7 I+b2 v, P A = 21 d) and B (O8 III+o9 v, P B = 6 d) are reasonably well sampled by the observations, allowing the origin of the X-ray emission to be examined in detail. The X-ray spectra can be well fitted by an attenuated three temperature thermal plasma model, characterised by cool, moderate, and hot plasma components at kT ≃ 0.2, 0.7, and 2 keV, respectively, and a circumstellar absorption of ≃ 0.2 × 10 22 cm −2 . Although the hot plasma component could be indicating the presence of wind-wind collision shocks in the system, the model fluxes calculated from spectral fits, with an average value of ≃ 7 × 10 −13 erg s −1 cm −2 , do not show a clear correlation with the orbits of the two constituent binaries. A semi-analytical model of QZ Car reveals that a stable momentum balance may not be established in either system A or B. Yet, despite this, system B is expected to produce an observed X-ray flux well in excess of the observations. If one considers the wind of the O8 III star to be disrupted by mass transfer the model and observations are in far better agreement, which lends support to the previous suggestion of mass-transfer in the O8 III + o9 v binary. We conclude that the X-ray emission from QZ Car can be reasonably well accounted for by a combination of contributions mainly from the single stars and the mutual wind-wind collision between systems A and B.

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Section: Discussionsupporting

confidence: 55%

X-Ray Emission From the Double-Binary Ob-Star System Qz Car (Hd 93206)

Parkin¹,

Broos²,

Townsley³

et al. 2011

ApJS

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“…Therefore, the X-ray emitting region must be far wider than the typical dimensions of the stars in the eclipsing binary. A similar situation was reported for β Lyrae (B6-8 IIp + B0 V, Ignace et al 2008), for which it was suggested that the X-rays arise in the wind of the B0 mass-gainer star and that the constancy of the X-ray flux is due to scattering in an extended halo from above and below the disk around the B0 star (Ignace et al 2008). In the case of Cyg OB2 #5, the X-ray emission could originate in various places.…”

Section: X-ray Datasupporting

confidence: 65%

A multiwavelength investigation of the massive eclipsing binary Cygnus OB2 #5

Linder¹,

Rauw²,

Manfroid³

et al. 2008

A&A

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Context. The properties of the early-type binary Cyg OB2 #5 have been debated for many years and spectroscopic and photometric investigations yielded conflicting results. Aims. We have attempted to constrain the physical properties of the binary by collecting new optical and X-ray observations. Methods. The optical light curves obtained with narrow-band continuum and line-bearing filters are analysed and compared. Optical spectra are used to map the location of the He ii λ 4686 and Hα line-emission regions in velocity space. New XMM-Newton as well as archive X-ray spectra are analysed to search for variability and constrain the properties of the hot plasma in this system. Results. We find that the orbital period of the system slowly changes though we are unable to discriminate between several possible explanations of this trend. The best fit solution of the continuum light curve reveals a contact configuration with the secondary star being significantly brighter and hotter on its leading side facing the primary. The mean temperature of the secondary star turns out to be only slightly lower than that of the primary, whilst the bolometric luminosity ratio is found to be 3.1. The solution of the light curve yields a distance of 925 ± 25 pc much lower than the usually assumed distance of the Cyg OB2 association. Whilst we confirm the existence of episodes of higher X-ray fluxes, the data reveal no phase-locked modulation with the 6.6 day period of the eclipsing binary nor any clear relation between the X-ray flux and the 6.7 yr radio cycle. Conclusions. The bright region of the secondary star is probably heated by energy transfer in a common envelope in this contact binary system as well as by the collision with the primary's wind. The existence of a common photosphere probably also explains the odd mass-luminosity relation of the stars in this system. Most of the X-ray, non-thermal radio, and possibly γ-ray emission of Cyg OB2 #5 is likely to arise from the interaction of the combined wind of the eclipsing binary with at least one additional star of this multiple system.

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“…The latter authors also postulated a second "bright spot" that should arise from a spiral arm that is formed within the disk. Some part of the gas flow is also deflected in the direction perpendicular to the accretion disk and forms a pair of jets, whose existence was first proposed by Harmanec et al (1996), and was confirmed by Hoffman et al (1998); Ak et al (2007); Ignace et al (2008); Bonneau et al (2011) via different types of observations. Observational evidence of the mass loss from the system has been presented by Umana et al (2000Umana et al ( , 2002, who resolved a circumbinary nebula surrounding the system in radio emission and found that it extends along the direction of the bipolar jets.…”

Section: Introductionmentioning

confidence: 83%

Physical properties ofβLyrae A and its opaque accretion disk

Mourard

Brož

Nemravová

et al. 2018

A&A

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Mass exchange and mass loss in close binaries can significantly affect their evolution, but a complete self-consistent theory of these processes is still to be developed. Processes such as radiative shielding due to a hot-spot region, or a hydrodynamical interaction of different parts of the gas stream have been studied previously. In order to test the respective predictions, it is necessary to carry out detailed observations of binaries undergoing the largescale mass exchange, especially for those that are in the rapid transfer phase. β Lyr A is an archetype of such a system, having a long and rich observational history. Our goal for this first study is to quantitatively estimate the geometry and physical properties of the optically thick components, namely the Roche-lobe filling mass-losing star, and the accretion disk surrounding the mass-gaining star of β Lyr A. A series of continuum visible and NIR spectro-interferometric observations by the NPOI, CHARA/MIRC and VEGA instruments covering the whole orbit of β Lyr A acquired during a two-week campaign in 2013 were complemented with UBVR photometric observations acquired during a three-year monitoring of the system. We included NUV and FUV observations from OAO A-2, IUE, and Voyager satellites. All these observations were compared to a complex model of the system. It is based on the simple LTE radiative transfer code SHELLSPEC, which was substantially extended to compute all interferometric observables and to perform both global and local optimization of system parameters. Several shapes of the accretion disk were successfully tested -slab, wedge, and a disk with an exponential vertical profile -and the following properties were consistently found: the radius of the outer rim is 30.0 ± 1.0 R , the semithickness of the disk 6.5 ± 1.0 R , and the binary orbital inclination i = 93.5 ± 1.0 deg. The temperature profile is a power-law or a steady-disk in case of the wedge geometry. The properties of the accretion disk indicate that it cannot be in a vertical hydrostatic equilibrium, which is in accord with the ongoing mass transfer. The hot spot was also detected in the continuum but is interpreted as a hotter part of the accretion disk illuminated by the donor. As a by-product, accurate kinematic and radiative properties of β Lyr B were determined.

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Phase-dependent X-ray observations of the β Lyrae system

Cited by 12 publications

References 23 publications

X-Ray Emission From the Double-Binary Ob-Star System Qz Car (Hd 93206)

X-Ray Emission From the Double-Binary Ob-Star System Qz Car (Hd 93206)

A multiwavelength investigation of the massive eclipsing binary Cygnus OB2 #5

Physical properties ofβLyrae A and its opaque accretion disk

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