Polarization of intrinsic radiation of tidally distorted stars with electron-scattering atmospheres

Bochkarev, N. G.; Karitskaya, E. A.; Шакура, Н. И.

doi:10.1007/bf00650116

Cited by 14 publications

(15 citation statements)

References 7 publications

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“…It is similar to ellipsoidal variation models computed by Mochnacki & Doughty (1972), Bochkarev et al (1979), Wilson & Devinney (1979), Hill (1979) and Tjemkes et al (1986). Somers et al (1996) added to the model an optically thick accretion disc, flared so as to be triangular in radial cross section, having a blackbody flux distribution and a radial temperature distribution for a steady state disc.…”

Section: Irradiation Of Secondary Stars By Hot White Dwarfssupporting

confidence: 57%

The decline in irradiation from the white dwarf in old novae

Thomas

Naylor

Norton

2008

A&A

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Aims. We have investigated how a flux ratio analysis of the light curves of cataclysmic variables can be used to calculate the luminosity irradiating the secondary star in the classical novae QU Vul, V Per, DD Cir, DN Gem, V1432 Aql, and WY Sge. Methods. We undertook phase-resolved, near-infrared K band photometry of QU Vul and V Per. Using data from QU Vul we show how flux ratios taken between fiducial orbital phases in the light curves of irradiated CVs can be used to measure the degree of heating of the secondary star. We compared the heating effect obtained from flux ratio analysis with more formal modelling, or by measurements taken from the literature, and found good agreement. We used the results to determine how irradiation changes with time since the nova outburst.Results. The light curve of QU Vul shows the presence of two maxima in the K band, which are displaced from phase 0.25 towards the 0.5 phase position, as would be expected from heating of the inner face of the secondary star by radiation from hot primary. Nova V Per, on the other hand shows evidence for a hot spot on the accretion disc, and it would appear that heating of the inner face is not occurring. The results of the flux ratio analysis of the objects examined are plotted as a function of time since the nova explosions occurred. There is marginal evidence for a decline in flux with time since the outburst, superimposed on considerable scatter, which is likely to be caused by the different temperature reached in each nova explosion. The decline is consistent with the declines others have seen. We conclude that it is the decline in reprocessed irradiation from the cooling white dwarf alone, rather than a decline in mass transfer rate, that could be the cause of the decrease in optical brightness seen in old novae.

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Section: Irradiation Of Secondary Stars By Hot White Dwarfssupporting

confidence: 57%

The decline in irradiation from the white dwarf in old novae

Thomas

Naylor

Norton

2008

A&A

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“…If the periodic signal is due to the ellipsoidality effect (Bochkarev, Karitskaya, & Shakura 1979) then the period found in the periodogram is half the orbital period because there are two modulations per orbit. In the I-band this would be especially true since the low mass M-S secondary would be prominent.…”

Section: Calypso Datamentioning

confidence: 99%

The First Orbital Period for a Dwarf Nova in a Globular Cluster: V101 in M5

Neill

Shara

Caulet

et al. 2002

The Astronomical Journal

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“…The amplitude of a light curve is defined as the difference in magnitudes between phases 0 and 0.5 and is generally a sensitive function of the inclination of the system. It provides an empirical correlation between the observations and the system parameters; see, for example, Bochkarev, Karitskaya & Shakura (1979). If the mass ratio q is known for a system, for example from radial velocity curves determined spectroscopically, it is common to use the light‐curve amplitude to deduce the orbital inclination and with it the component masses, which are proportional to sin i to the third power.…”

Section: Binary Systems Containing An Accretion Discmentioning

confidence: 99%

Irradiation pressure effects in close binary systems

Phillips¹,

Podsiadlowski²

2002

Monthly Notices of the Royal Astronomical Society

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We present a method for the calculation of the effects of external irradiation on the geometrical shape of the secondary in a close binary containing a compact star, the source of the radiation, and a normal companion star, where we include the possibility of shadowing by an accretion disc. The model is based on a simple modification of the standard Roche binary potential in which the radiation pressure force is parametrized using the ratio of the radiation to the gravitational force. We have constructed numerical solutions of approximate three-dimensional irradiated equipotential surfaces to demonstrate the main geometrical effects of external radiation pressure. For systems in which the inner Lagrangian point is irradiated directly and for sufficiently high irradiation fluxes, the critical condition for which the secondary fills its tidal lobe changes from an inner to an outer critical configuration, where the critical equipotential surface connects to one of the outer rather than inner Lagrangian points. Such a situation may apply to evaporating binary pulsar systems (e.g. PSR 1957 + 20), stars orbiting supermassive black holes in AGN and some high-mass X-ray binaries (HMXBs, including Centaurus X-3). For systems containing an accretion disc, which shadows the inner Lagrangian point from the external irradiation, the presence of significant radiation pressure causes a non-axisymmetric deformation of the stellar surface. This has particularly important consequences for low-mass X-ray binaries, for which the X-ray luminosities can be close to the Eddington limit. We have calculated modified Roche potentials to determine the main effects on the optical light curves and radial velocity curves for typical binary parameters. Compared to previous studies, the inclusion of irradiation pressure effects results in changes in the derived system parameters (e.g. component masses, radial velocities) that may be as high as ∼30 per cent. We conclude that the proper inclusion of irradiation pressure effects is essential for a reliable analysis of close binary systems in which the secondaries are strongly irradiated.

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Polarization of intrinsic radiation of tidally distorted stars with electron-scattering atmospheres

Cited by 14 publications

References 7 publications

The decline in irradiation from the white dwarf in old novae

The decline in irradiation from the white dwarf in old novae

The First Orbital Period for a Dwarf Nova in a Globular Cluster: V101 in M5

Irradiation pressure effects in close binary systems

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