Hamid M. K. Al-Naimiy

Linearized limb-darkening coefficients for use in analysis of eclipsing binary light curves

Linear limb-darkening coefficientsu required in the analysis of eclipsing binary curves, are tabulated for a wide range of effective temperature (50 000° to 4000°), wavelength λ (0.2 μ≤λ≤2.2 μ), and gravitiesg (2.0≤logg≤5.0). The computation is based on the comprehensive range of model atmospheres of Carbon and Gingerich (1969).The results are compared with the theoretical values of Hosokawa (1957), Kopal (1959) and Grygaret al. (1972), and examined in relation to empirically determined values ofu from analyses of eclipsing binary light curves. An improved agreement between theory and observation for the calculated limb-darkening coefficients of the present work is noted.

Analysis of red and infrared wide-band photometry of Algol

The basic physical picture of the Algol system is reviewed, and, using collected red and infrared observations, photometric curve fits are investigated by applying numerical quadratures to determine theoretical light curves appropriate to Roche model stars. The ‘contact’ nature of Algol B appears to be confirmed, and effective temperatures of the three components areTA=11 400°,TB=5300°,TC=7600°. In terms of a Lamberts law approach to the ‘reflection effect’, the effective heat-albedo is required to be reduced from unity to one half; and it is also found that the averaged ‘gravity-darkening coefficient’ is close to a value appropriate for a diffusion type of heat-transfer mechanism operating in sub-photospheric layers.

Determination of the elements of eclipsing variables, RW Gem and AY Cam, by Fourier analysis of their light changes

The aim of the present paper has been to present an analysis of the light curve of two eclipsing systems RW Gem and AY Cam by Fourier analysis of the light changes in the frequency domain which was developed by Kopal (1975a, b, c, d, e; 1976).In Section 1, the subject is introduced in a general way, with the intention of laying the foundation of the light curve analysis. Section 2 contains the evaluation of the empirical values of the theoretical momentA2m is demonstrated, with the equation of the condition given. Then the equations forA2m in terms of the elements of the total and the annular eclipses, including partial and annular phase of transit eclipse, follow.The analysis of the light curves of the two eclipsing binaries (RW Gem and AY Cam), the results and the discussion of our solution, are outlined in Section 3.

Fourier analysis of the light changes of four Algol-type eclipsing variables

The aim of the present paper is to present the analysis of the light curves of four totally-eclipsing systems (BM Ori, VW Cyg, TW Dra, and RW Mon), using the automated Fourier techniques in the frequency-domain, developed recently by Kopal and his school at Manchester University.New Physical and geometrical elements for the above systems are derived.

UBV photometry and light-curve analysis of Algol

AbstractPhotoelectric observations of the eclipsing variable β Per, were obtained inUBV standard system, and new elements for the primary minimum were determined as

Fourier analysis of the light changes of eclipsing variables in the frequency-domain

J.D. = 2445641.5135,O - C = 0_.^d 0.009.

New photoelectric observations and light curve analysis of 44i bootis

The light curves of the system were analysed using Fourier techniques in the frequency-domain. The fractional radii of both components are