EDP Sciences
Free access
Volume 499, Number 2, May IV 2009
Page(s) L13 - L16
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361/200811609
Published online 29 April 2009
A&A 499, L13-L16 (2009)
DOI: 10.1051/0004-6361/200811609


Dynamical stability of the inner belt around Epsilon Eridani

M. Brogi1, F. Marzari2, and P. Paolicchi1

1  University of Pisa, Department of Physics, Largo Pontecorvo 3, 56127 Pisa, Italy
    e-mail: matbrogi@gmail.com; paolicchi@df.unipi.it
2  University of Padua, Department of Physics, via Marzolo 8, 35131 Padua, Italy
    e-mail: marzari@pd.infn.it

Received 31 December 2008 / Accepted 17 April 2009

Context. Recent observations with Spitzer and the Caltech Submillimeter Observatory have discovered the presence of a dust belt at about 3 AU, internal to the orbit of known exoplanet $\epsilon$ Eri b.
Aims. We investigate via numerical simulations the dynamical stability of a putative belt of minor bodies, as the collisional source of the observed dust ring. This belt must be located inside the orbit of the planet, since any external source would be ineffective in resupplying the inner dust band.
Methods. We explore the long-term behaviour of the minor bodies of the belt and how their lifetime depends on the orbital parameters of the planet, in particular for reaching a steady state.
Results. Our computations show that for an eccentricity of $\epsilon$ Eri b equal or higher than 0.15, the source belt is severely depleted of its original mass and substantially reduced in width. A “dynamical” limit of ${\simeq}$0.10 comes out, which is inconsistent with the first estimate of the planet eccentricity (0.70$\pm$0.04), while the alternate value (0.23$\pm$0.2) can be consistent within the uncertainties.

Key words: stars: planetary systems -- minor planets -- asteroids -- celestial mechanics -- stars: individual: Epsilon Eridani

© ESO 2009