Astron. Astrophys. Suppl. Ser. 132, 367-379

Physical parameters of the Algol system TZ Eridani from simultaneous analysis of Geneva 7-colour light curves

F. Barblan ¹ - P. Bartholdi ¹ - P. North ² - G. Burki ¹ - E.C. Olson ³

Send offprint request: F. Barblan

1 - Geneva Observatory, CH-1290 Sauverny, Switzerland
2 - Institut d'Astronomie de l'Université de Lausanne, CH-1290 Chavannes-des-Bois, Switzerland
3 - Astronomy Department, University of Illinois, 1002 W. Green St., Urbana, Illinois 61801, U.S.A.

Received March 27; accepted May 11, 1998

Abstract:

Light curves of the semi-detached eclipsing binary system TZ Eridani in the Geneva 7-colour photometric system were analysed using the Wilson-Devinney programme. The physical and orbital parameters have been determined through a self-consistent simultaneous solution of the seven light curves and of the radial velocity curves of both components. The following absolute elements of the components are, for the primary (mass gainer), $M_1 = 1.97 \pm 0.06$$M_{\odot}$, $R_1 = 1.69 \pm$ 0.03 $R_{\odot}$, $M_{\rm bol_1} = 2.36 \pm 0.09$, $T_{\rm eff_1} = 7770 \pm 100$ K, and for the secondary (mass loser), $M_2 = 0.37 \pm 0.01$ $M_{\odot}$, $R_2 = 2.60 \pm 0.04$$R_{\odot}$, $M_{\rm bol_2} = 3.74 \pm 0.13$, $T_{\rm eff_2} = 4570\ \pm$100 K. The semi-major axis A of the relative orbit is $10.57 \pm$ 0.16 $R_{\odot}$. The regular increase of the period is described. The spectral type of the components are A5/6 V (primary) and K0/1 III. The secondary has exhibited a long-term luminosity increase of about 0.06 in V between Dec. 1983 and Dec. 1996. The distance to TZ Eri is evaluated to 270 $\pm$ 12 pc.

Key words: stars: individual: TZ Eridani -- binaries: eclipsing -- stars: fundamental parameters