2 6 N ov 2 01 3 A Detailed Analysis of the HD 73526 2 : 1 Resonant Planetary System

We present six years of new radial-velocity data from the Anglo-Australian and Magellan Telescopes on the HD73526 2:1 resonant planetary system. We investigate both Keplerian and dynamical (interacting) fits to these data, yielding four possible configurations for the system. The new data now show that both resonance angles are librating, with amplitudes of 40 and 60, respectively. We then perform long-term dynamical stability tests to differentiate these solutions, which only differ significantly in the masses of the planets. We show that while there is School of Physics, University of New South Wales, Sydney 2052, Australia Australian Centre for Astrobiology, University of New South Wales, Sydney 2052, Australia Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, 1629 University Boulevard, Tucson, AZ 85721, USA Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015-1305, USA Faculty of Sciences, University of Southern Queensland, Toowoomba, Queensland 4350, Australia University of Hertfordshire, Centre for Astrophysics Research, Science and Technology Research Institute, College Lane, AL10 9AB, Hatfield, UK Australian Astronomical Observatory, PO Box 915, North Ryde, NSW 1670, Australia The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101, USA Institute of Astrophysics, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22, Chile Vatican Observatory, V00120 Vatican City State, Italy