Astrophysics and Space Science

, Volume 162, Issue 2, pp 211–234 | Cite as

A photometric light variation and a 1500 days secondary period in the W UMa system TZ bootis

  • Nabil S. Awadalla


Photoelectric observations of the eclipsing variable TZ Bootis, obtained in 1983 and 1986, in the two coloursB andV are presented: They are compared with the previous light curves of the system. The light curve changes show that the system TZ Bootis has a solar-like activity cycle with a period of 1500 days. The primary shows a transit, whereas the secondary shows an occultation minima. The maxima exhibit a large difference suggesting a large complication in the system. The (O-C) trend indicates that the period did not remain constant; a satisfactory representation of all the observed time of minimum light was obtaiend assuming a linear trend in the (O-C)s. The star may be classified to A-type W UMa systems.


Linear Trend Light Curve Activity Cycle Light Curf Curve Change 


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  1. Al-Naimiy, H. M. K.: 1982,Astron. J. 87(7), 104.Google Scholar
  2. Binnendijk, L.: 1969,Astron. J.,74(2), 211.Google Scholar
  3. Binnendijk, L.: 1970,Vistas Astron. 12, 217.Google Scholar
  4. Carr, R. B.: 1971,Publ. of Goodsell Obs., No. 16.Google Scholar
  5. Chang, Y. C.: 1948,Astrophys. J. 107, 101.Google Scholar
  6. Eggen, O. J.: 1967,Mem. Roy. Astron. Soc. 70, Pt. 4, 111.Google Scholar
  7. Güdür, N., Ibaňoglu, C., Gülmen, O., and Bozkurt, S.: 1976,IAU Commission 27 Information Bulletin on Variable Stars, No. 1086.Google Scholar
  8. Guthnick, P. and Prager, R.: 1927,Kl. Veröff. Berlin-Babelsberg, No. 4, 8.Google Scholar
  9. Hoffmann, M.: 1978a,Astron. Astrophys. Suppl. 33, 63.Google Scholar
  10. Hoffmann, M.: 1978b,IAU Commission 27 Information Bulletin on Variable Stars, No. 1487.Google Scholar
  11. Hoffmann, M.: 1980a,Astron. Astrophys. Suppl. 40, 263.Google Scholar
  12. Hoffmann, M.: 1980b,IAU Commission 27 Information Bulletin on Variable Stars, No. 1877.Google Scholar
  13. Hoffmann, M.: 1981,IAU Commission 27 Information Bulletin on Variable Stars No. 1980.Google Scholar
  14. Kaluzny, J.: 1985,Acta Astron. 35, 313.Google Scholar
  15. Koch, R. H.: 1956,Astron. J. 61, 47.Google Scholar
  16. Kukarkin, B. V., Kholopov, P. N., Efremov, Y. N., Kukarkina, N. P., Kurochkin, N. E., Medvedeva, G. I., Perova, N. B., Fedorovich, V. P., and Frolov, M. S.: 1970,General Catalogue of Variable Stars, Nauka, Moscow.Google Scholar
  17. Matese, J. J. and Whitmore, D. P.: 1983,Astron. Astrophys. 117, L7.Google Scholar
  18. Wilson, O. C.: 1978,Astrophys. J. 226, 379.Google Scholar
  19. Wolfschmidt, G., Rahe, J., and Shoffel, E.: 1979,Mitt. Astron. Ges. 45.Google Scholar

Copyright information

© Kluwer Academic Publishers 1989

Authors and Affiliations

  • Nabil S. Awadalla
    • 1
    • 2
  1. 1.Physics DepartmentUniversity of BahrainBahrainEgypt
  2. 2.Helwan Institute of Astronomy and GeophysicsCairoEgypt

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