Astrobiology Workshop, Macquarie University July 12-13 2001

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A Planet in the Alpha Centauri System ?

Graeme White (University of Western Sydney)

The bright southern sky double star, Alpha Centauri, has been observed since 1752 and today there are 474 astrometric observations of this system. It is also the closest system to Earth and the 3rd brightest system in the sky; an obvious place to apply astrometric methods of planetary detection. However, such work has been handicapped by the belief that planetary orbits would be unstable in such a dynamic system. This is not the case and two stable regions have been identified in which a planet may be found (Weigert P.A., & Holman M.J., 1997).

Our Fourier analysis of perturbations and modeling of this system have placed an upper limit on the mass of any new component that may exist in this system that lies within the stable orbital region within ~2 AU of Alpha Centauri A and/or B.