Astrophysics and Space Science

, Volume 331, Issue 1, pp 121–126 | Cite as

The (O–C) diagram problem of triple pre-cataclysmic system V471 Tau solved

  • E. KundraEmail author
  • L. Hric
Original Article


V471 Tau was discovered as a spectroscopic binary by Wilson (General Catalogue of Stellar Radial Velocities, p. 44, 1953). It is the prototype of a post-common envelope system and a progenitor of a cataclysmic binary. The system consists of a cool red dwarf, K2 V, very probably a main sequence star and a hot white dwarf. The object was classified as a close binary with an orbital period of around 0.5 days. Moreover, on the light curve are observed light variations with a period of 191 days, which are connected with an ellipsoidal shape of the red dwarf as well as with the migration of spots on the surface of this cool component. The eclipse of the white dwarf in the binary remains 49 minutes and declines to the minimum and the increase from the minimum takes only 55 s. Such photometric behaviour hinders obtaining good eclipses. In this paper we have obtained during four years seven eclipses with high time resolution with all four contacts to reach precise times of minima. Fortunately these times of the minima show a change of trend in the (O–C) diagram, and we were able to decide about the physical processes responsible for the behaviour of the (O–C) diagram. We showed that this behaviour is caused by a third body in the system with an orbital period of 33.2 years, and its physical and geometrical parameters are presented. For an inclination larger than 35° we get the mass of this body below the stable hydrogen-burning limit and thus most probably the candidate would be a brown dwarf.


Stars Binaries Eclipsing-stars Individual V471 Tau-stars Cataclysmic variables 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bond, H.E.: Astrophys. Space Sci. Libr. 113, 15 (1985) ADSCrossRefGoogle Scholar
  2. Budaj, J., Komžík, R.M.: In: EQWREC2 (2001).
  3. de Bruijne, J.H.J., Hoogerwerf, R., de Zeeuw, P.T.: Astron. Astrophys. 367, 111 (2001) CrossRefADSGoogle Scholar
  4. Drake, J.J., Sarna, M.J.: Astrophys. J. 594, L55 (2003) CrossRefADSGoogle Scholar
  5. Evren, S., Ibanoglu, C., Tunca, Z., Tümer, O.: Astrophys. Space Sci. 120, 97 (1985) CrossRefADSGoogle Scholar
  6. Guinan, E.F., Ribas, I.: Astrophys. J. 546, L43 (2001) CrossRefADSGoogle Scholar
  7. Guinan, E.F., Sion, E.M.: Astron. J. 89, 1252 (1984) CrossRefADSGoogle Scholar
  8. Hric, L., Petrík, K., Niarchos, P., Gális, R.: Astrophys. Space Sci. Libr. 298, 207 (2003) ADSGoogle Scholar
  9. Hric, L., Kundra, E., Dubovský, P.: CAOSP (2010, in press) Google Scholar
  10. Hussain, G.A.J., Allende Prieto, C., Saar, S.H., Still, M.: Mon. Not. R. Astron. Soc. 367, 1699 (2006) CrossRefADSGoogle Scholar
  11. Ibanoglu, C., Keskin, V., Akan, M.C., Evren, S., Tunca, Z.: Astron. Astrophys. 281, 811 (1994) ADSGoogle Scholar
  12. Ibanoglu, C., Evren, S., Tas, G., Cakirh, Ö.: Mon. Not. R. Astron. Soc. 360, 1077 (2005) CrossRefADSGoogle Scholar
  13. Kamiński, K.Z., Ruciński, S.M., Matthews, J.M., Kuschnig, R., Rowe, J.F., Guenther, D.B., Moffat, A.F.J., Sasselov, D., Walker, G.A.H., Weiss, W.W.: Astron. J. 134, 1206 (2007) CrossRefADSGoogle Scholar
  14. Motl, D.: C-Munipack (2004).
  15. Nelson, B., Young, A.: Publ. Astron. Soc. Pac. 82, 699 (1970) CrossRefADSGoogle Scholar
  16. Paczynski, B.: In: IAU Symp. 73: Structure and Evolution of Close Binary Systems, p. 75 (1976) Google Scholar
  17. Pribulla, T., Chochol, D., Tremko, J., Kreiner, J.M.: Publ. Astron. Soc. Pac. 335, 103 (2005) Google Scholar
  18. Provencal, J., Shipman, H., Hoeg, E., Thejll, P.: Bull. Am. Astron. Soc. 28, 1380 (1996) ADSGoogle Scholar
  19. Ramseyer, T.F., Hatzes, A.P., Jablonski, F.: Astron. J. 110, 1364 (1995) CrossRefADSGoogle Scholar
  20. Wheatley, P.J.: Mon. Not. R. Astron. Soc. 297, 1145 (1998) CrossRefADSGoogle Scholar
  21. Wilson, R.E.: General Catalogue of Stellar Radial Velocities, p. 44 (1953) Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.Astronomical InstituteSlovak Academy of SciencesTatranská LomnicaSlovakia

Personalised recommendations