...O. Absil^1,

O.A. acknowledges the financial support of the Belgian National Fund for Scientific Research (FNRS).

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... estimates

The K-band diameter proposed by Ciardi et al. (2001) was computed with the assumption of a flat spectrum for the Vega intensity. This explains a large part of the discrepancy with our new value.

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... 6.3 mas

The astrometric signature of a low-mass companion is given by the ratio between the orbital semi-major axis and the mass ratio (Perryman 2000).

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...Kelsall et al. (1998)

This model was implemented in an IDL package called ZODIPIC by M. Kuchner (http://www.astro.princeton.edu/~mkuchner/).

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