Astrophysics and Space Science

, Volume 115, Issue 2, pp 243–249 | Cite as

Free precession of Cyg X-3 and the 34.1-day periodicity

  • Yasushi Suto
  • Ken-Ichi Iso


The origin of the 34.1-day periodicity in X-ray and γ-ray from Cyg X-3 has not been made clear so far. In this paper, we propose a free precession model for an elastic neutron star. This model explains the 34.1-day periodicity and predicts the unobserved spin period for Cyg X-3 to be about 100 ms. Taking into account the possibility that the secular spin angular velocity of the star is different from that observed presently, the analogous long-terms periodicities of Her X-1 and Cen X-3 are also accounted for in this theory.


Angular Velocity Neutron Star Free Precession Spin Period Elastic Neutron 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© D. Reidel Publishing Company 1985

Authors and Affiliations

  • Yasushi Suto
    • 1
  • Ken-Ichi Iso
    • 1
  1. 1.Department of Physics, Faculty of ScienceUniversity of TokyoJapan

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