On the dynamics of the AB Doradus system

J. C. Guirado (1) , Ivan Marti-Vidal (1) , Juan-María Marcaide (1) , Laird M. Close (2) , J. C. Algaba (1) , W. Brandner (3) , Jean-François Lestrade (4) , D. L. Jauncey (5) , D. L. Jones (6) , Robert A. Preston (6) , John E. Reynolds (5)

1 UV - Universitat de València
2 Steward Observatory, University of Arizona
3 MPIA - Max-Planck-Institut für Astronomie
4 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
5 ATNF - Australian Telescope National Facility
6 JPL - Jet Propulsion Laboratory

We present an astrometric analysis of the binary systems AB Dor A /AB Dor C and AB Dor Ba /AB Dor Bb. These two systems of well-known late-type stars are gravitationally associated and they constitute the quadruple AB Doradus system. From the astrometric data available at different wavelengths, we report: (i) a determination of the orbit of AB Dor C, the very low mass companion to AB Dor A, which confirms the mass estimate of 0.090 M_&sun; reported in previous works; (ii) a measurement of the parallax of AB Dor Ba, which unambiguously confirms the long-suspected physical association between this star and AB Dor A; and (iii) evidence of orbital motion of AB Dor Ba around AB Dor A, which places an upper bound of 0.4 M_&sun; on the mass of the pair AB Dor Ba /AB Dor Bb (50% probability). Further astrometric monitoring of the system at all possible wavelengths would determine with extraordinary precision the dynamical mass of its four components.

Domaines: Astrophysique [astro-ph]; Planète et Univers [physics]

J. C. Guirado, Ivan Marti-Vidal, Juan-María Marcaide, Laird M. Close, J. C. Algaba, et al.. On the dynamics of the AB Doradus system. Astronomy and Astrophysics - A&A, 2006, 446, pp.733-738. ⟨10.1051/0004-6361:20053757⟩. ⟨hal-03732481⟩