The Be/X-ray transient 4U 0115+63/V635 Cassiopeiae

Negueruela, I.; Okazaki, Atsuo T.; Fabregat, J.; Coe, M. J.; Munari, U.; Tomov, T.

doi:10.1051/0004-6361:20010077

Cited by 106 publications

(95 citation statements)

References 27 publications

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“…3.1, the rotational velocities given in Table 3 and the peak separation of the first available asymmetric profile after the disc loss, namely, Δ peak = 220 km s −1 (X-Per, Clark et al 2001), Δ peak = 305 km s −1 (4U 0115+63, Negueruela et al 2001), we find that the disc must reach a radius of ∼4 R * for the onset of the V/R variability. Virtually the same value is derived from Fig.…”

Section: Discussionmentioning

confidence: 62%

The optical counterpart to IGR J06074+2205: a Be/X-ray binary showing disc loss andV/Rvariability

Reig

Zezas

Gkouvelis

2010

A&A

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Context. Current X-ray missions are regularly discovering new X/γ-ray sources, so identifying the counterparts of these high-energy sources at other wavelengths is important for determining their nature. In particular, optical observations are crucial in the study of X-ray binary populations in our Galaxy. Aims. The main goal of this work is to determine the properties of the optical counterpart to the INTEGRAL source IGR J06074+2205 and study its long-term optical variability. Although its nature as a high-mass X-ray binary has been suggested, little is known about its physical parameters. Methods. We have been monitoring IGR J06074+2205 since 2006 in the optical band. We present optical photometric BVRI and spectroscopic observations covering the wavelength band 4000−7000 Å. The blue spectra allow us to determine the spectral type and luminosity class of the optical companion and the red spectra, together with the photometric magnitudes, were used to derive the colour excess E(B − V) and estimate the distance. Results. We have carried out the first detailed optical study of the massive component in the high-mass X-ray binary IGR J06074+2205. We find that the optical counterpart to IGR J06074+2205 is a V = 12.3 B0.5Ve star located at a distance of ∼4.5 kpc. Monitoring of the Hα line reveals V/R variability and an overall decline in its equivalent width. The Hα line has been seen to revert from an emission to an absorption profile. We attribute this variability to global changes in the structure of the Be star's circumstellar disc that eventually led to the complete loss of the disc. The density perturbation that gives rise to the V/R variability vanishes when the disc becomes too small.

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Section: Discussionmentioning

confidence: 62%

The optical counterpart to IGR J06074+2205: a Be/X-ray binary showing disc loss andV/Rvariability

Reig

Zezas

Gkouvelis

2010

A&A

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“…Rappaport et al (1978) determined the binary's main parameters: orbital period ∼ 24.3 days, orbital eccentricity 0.34, and projected semimajor axis of the relativistic object axsini ∼ 140 light seconds (see also Tamura et al, 1992;Lutovinov et al, 1994, for an improvement of the parameters). The optical observations of the star V635 Cas Kholopov et al, 1981), which is the normal stellar companion of the X-ray source 4U 0115+63, performed by Negueruela and Okazaki (2001) allowed the star's spectral type to be improved, B0.2Ve, and the binary's distance to be estimated, 7-8 kpc. The X-ray pulsar 4U 0115+63 is unique in its spectral characteristics.…”

Section: Discussionmentioning

confidence: 99%

High-mass X-ray binaries in the Milky Way

Walter

Lutovinov

Bozzo

et al. 2015

Astron Astrophys Rev

234

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High-mass X-ray binaries are fundamental in the study of stellar evolution, nucleosynthesis, structure and evolution of galaxies and accretion processes. Hard X-rays observations by INTEGRAL and Swift have broadened significantly our understanding in particular for the super-giant systems in the Milky Way, which number has increased by almost a factor of three. INTEGRAL played a crucial role in the discovery, study and understanding of heavily obscured systems and of fast X-ray transients. Most super-giant systems can now be classified in three categories: classical/obscured, eccentric and fast transient.The classical systems feature low eccentricity and variability factor of ∼ 10 3 , mostly driven by hydrodynamic phenomena occurring on scales larger than the accretion radius. Among them, systems with short orbital periods and close to Roche-Lobe overflow or with slow winds, appear highly obscured. In eccentric systems, the variability amplitude can reach even higher factors, because of the contrast of the wind density along the orbit. Four super-giant systems, featuring fast outbursts, very short orbital periods and anomalously low accretion rates, are not yet understood.Simulations of the accretion processes on relatively large scales have progressed and reproduce parts of the observations. The combined effects of wind

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“…Kato et al (1978) showed that m = 1 modes in nearly Keplerian disks, which are neutral if viscosity is neglected, become overstable when viscous effects are taken into account. The growth rate is proportional to α (see also Negueruela et al 2001).…”

Section: Disk Structurementioning

confidence: 99%

Cyclic variability of the circumstellar disk of the Be starζTauri

Carciofi¹,

Okazaki

Bouquin

et al. 2009

A&A

Self Cite

118

162

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Context. About 2/3 of the Be stars present the so-called V/R variations, a phenomenon characterized by the quasi-cyclic variation in the ratio between the violet and red emission peaks of the H i emission lines. These variations are generally explained by global oscillations in the circumstellar disk forming a one-armed spiral density pattern that precesses around the star with a period of a few years. Aims. This paper presents self-consistent models of polarimetric, photometric, spectrophotometric, and interferometric observations of the classical Be star ζ Tauri. The primary goal is to conduct a critical quantitative test of the global oscillation scenario. Methods. Detailed three-dimensional, NLTE radiative transfer calculations were carried out using the radiative transfer code HDUST. The most up-to-date research on Be stars was used as input for the code in order to include a physically realistic description for the central star and the circumstellar disk. The model adopts a rotationally deformed, gravity darkened central star, surrounded by a disk whose unperturbed state is given by a steady-state viscous decretion disk model. It is further assumed that this disk is in vertical hydrostatic equilibrium. Results. By adopting a viscous decretion disk model for ζ Tauri and a rigorous solution of the radiative transfer, a very good fit of the time-average properties of the disk was obtained. This provides strong theoretical evidence that the viscous decretion disk model is the mechanism responsible for disk formation. The global oscillation model successfully fitted spatially resolved VLTI/AMBER observations and the temporal V/R variations in the Hα and Brγ lines. This result convincingly demonstrates that the oscillation pattern in the disk is a one-armed spiral. Possible model shortcomings, as well as suggestions for future improvements, are also discussed.

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The Be/X-ray transient 4U 0115+63/V635 Cassiopeiae

Cited by 106 publications

References 27 publications

The optical counterpart to IGR J06074+2205: a Be/X-ray binary showing disc loss andV/Rvariability

The optical counterpart to IGR J06074+2205: a Be/X-ray binary showing disc loss andV/Rvariability

High-mass X-ray binaries in the Milky Way

Cyclic variability of the circumstellar disk of the Be starζTauri

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