Formation and structure of the three Neptune-mass planets system around HD69830 - Archive ouverte HAL
Pré-Publication, Document De Travail Année : 2006

Formation and structure of the three Neptune-mass planets system around HD69830

Yann Alibert
Isabelle Baraffe
  • Fonction : Auteur
Willy Benz
  • Fonction : Auteur
Gilles Chabrier
  • Fonction : Auteur
Christophe Mordasini
  • Fonction : Auteur
Christophe Lovis
Michel Mayor
  • Fonction : Auteur
Francesco Pepe
  • Fonction : Auteur
Didier Queloz
Stephane Udry
  • Fonction : Auteur

Résumé

Since the discovery of the first giant planet outside the solar system in 1995 (Mayor & Queloz 1995), more than 180 extrasolar planets have been discovered. With improving detection capabilities, a new class of planets with masses 5-20 times larger than the Earth, at close distance from their parent star is rapidly emerging. Recently, the first system of three Neptune-mass planets has been discovered around the solar type star HD69830 (Lovis et al. 2006). Here, we present and discuss a possible formation scenario for this planetary system based on a consistent coupling between the extended core accretion model and evolutionary models (Alibert et al. 2005a, Baraffe et al. 2004,2006). We show that the innermost planet formed from an embryo having started inside the iceline is composed essentially of a rocky core surrounded by a tiny gaseous envelope. The two outermost planets started their formation beyond the iceline and, as a consequence, accrete a substantial amount of water ice during their formation. We calculate the present day thermodynamical conditions inside these two latter planets and show that they are made of a rocky core surrounded by a shell of fluid water and a gaseous envelope.

Dates et versions

hal-00129138 , version 1 (06-02-2007)

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Yann Alibert, Isabelle Baraffe, Willy Benz, Gilles Chabrier, Christophe Mordasini, et al.. Formation and structure of the three Neptune-mass planets system around HD69830. 2006. ⟨hal-00129138⟩
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