Dynamical parallax

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In astronomy, the distance to a visual binary star may be estimated from the masses of its two components, the size of their orbit, and the period of their revolution around one another.[1] A dynamical parallax is an (annual) parallax which is computed from such an estimated distance.

To calculate a dynamical parallax, the angular semi-major axis of the orbit of the stars around each other is observed, together with their apparent brightness. By using Newton's generalisation of Kepler's Third Law, which states that the total mass of a binary system multiplied by the square of its orbital period is proportional to the cube of its semi-major axis[2], together with the mass-luminosity relation, the distance to the binary star can then be determined. [3]

[edit] References

  1. ^ Patrick Moore (2002). Philip's Astronomy Encyclopedia, revised and expanded ed. (in English), London: Philip's, 120. ISBN 0540078638. 
  2. ^ dynamical parallax (HTML) (English). Astronomy Knowledge Base. Retrieved on 2006-07-18.
  3. ^ The Mass-Luminosity Relation, University of Tennessee, Astronomy 162: Stars, Galaxies, and Cosmology, lecture notes. Accessed July 18, 2006.
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