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ASP Conference Series, Vol. 145, 1998

Editors: R. Albrecht, R. N. Hook and H. A. Bushouse

**Grzegorz Poubek**

Astronomical Institute of the Wrocaw University
PL-51-622 Wrocaw, ul. Kopernika 11, Poland

The photospheres of eclipsing components are represented by a
grid of surface elements, which are treated as
plane-parallel and homogeneous ones.
In order to calculate the synthetic fluxes of radiation an integration
over all surface elements visible at a given orbital
phase, , should be done.
For this purpose geometrical parameters (i.e., area of elements
and their positions) as well as physical ones (temperatures and surface
gravities) for all elements have to be known.
To describe the system's geometry we assumed the Roche model
presented by Kopal (1959) and
Limber (1963) for synchronous and nonsynchronous rotation,
respectively.

Assuming synchronous rotation of the components, the total potential can be written as:

(1) |

(2) |

(3) |

The local surface gravity follows from the equation

(4) |

If we take into account the irradiation effect, the local temperatures have to be modified. For this purpose an iterative procedure based on the Chen & Rhein (1969) approach was used. In the first step, the intrinsic effective temperatures of both components were set. Then, for each surface element (

(5) |

(6) |

(7) |

We analyse UV spectra of Algol collected by
the IUE satellite.
We use 15 pairs of IUE spectra from short wavelength primary
(SWP) and long wavelength primary (LWP) cameras.
We found (Algol A) = 13000 K,
(Algol B) = 5000 K,
(Algol C) = 7000 K,
= and other parameters similar to those
given by Tomkin & Lambert (1978). The best-fit solution for the
three pairs of spectra is displayed in Figure 2.
This model was further verified by *UBV* observations of
Algol taken from Wilson et al. (1972) and by the infrared
observations of Chen & Reuning (1966).
The comparison of these observations with the theoretical
light curves are shown in Figure 3.

This work was supported by the research grant No. 2 P03D 001 08 from the Polish Scientific Research Committee (KBN).

Chen, K.-Y., & Reuning, E. G., 1966, AJ, 71, 283

Chen, K. -Y., & Rhein, W. J., 1969, PASP, 81, 387

Kopal, Z., 1959, Close Binary Systems, International Astrophysics Series Vol. 5

Kurucz, R.L., 1996, CD-ROM No.19

Limber, D.N., 1963, ApJ, 138, 1112

Lucy, L.B., 1967, Z. Astrophys., 65, 89

Rucinski, S.M., 1969, Acta Astron., **19**, 245

Tomkin, J., & Lambert, D. L., 1978, ApJ, 222, L119

Wade, R. A., & Rucinski, S. M., 1985, A&AS, 60, 471

Wilson, R. E., DeLuccia, M. R., Johnson, K., & Mango, S. A., 1972, ApJ, 177, 191

von Zeipel, H., 1924, MNRAS, 84, 702

© Copyright 1998 Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, California 94112, USA

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