EDP Sciences
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Volume 396, Number 1, December II 2002
Page(s) 219 - 224
Section Formation and evolution of planetary systems
DOI http://dx.doi.org/10.1051/0004-6361:20021357

A&A 396, 219-224 (2002)
DOI: 10.1051/0004-6361:20021357

Formation of terrestrial planets in close binary systems: The case of $\alpha$ Centauri A

M. Barbieri1, F. Marzari2 and H. Scholl3

1  CISAS, c/o Dipartimento di Fisica, Università di Padova, via Marzolo 8, 35131 Padova, Italy
    e-mail: mbarbier@pd.infn.it
2  Dipartimento di Fisica, Università di Padova, via Marzolo 8, 35131 Padova, Italy
    e-mail: marzari@pd.infn.it
3  Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4, France
    e-mail: scholl@obs-nice.fr

(Received 3 April 2002 / Accepted 22 August 2002)

At present the possible existence of planets around the stars of a close binary system is still matter of debate. Can planetary bodies form in spite of the strong gravitational perturbations of the companion star? We study in this paper via numerical simulation the last stage of planetary formation, from embryos to terrestrial planets in the $\alpha$ Cen system, the prototype of close binary systems. We find that Earth class planets can grow around $\alpha$ Cen A on a time-scale of 50 Myr. In some of our numerical models the planets form directly in the habitable zone of the star in low eccentric orbits. In one simulation two of the final planets are in a 2:1 mean motion resonance that, however, becomes unstable after 200 Myr. During the formation process some planetary embryos fall into the stars possibly altering their metallicity.

Key words: planetary nebulae: general

Offprint request: M. Barbieri, mbarbier@pd.infn.it

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