Based on observations collected at the European Southern Observatory, Paranal, Chile, within the guaranteed time programme 074.A-9025(A).

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

Note that this analysis is valid as long as the continuum emission is resolved. In our case the continuum is calibrated by a model and not by an unresolved star, and therefore there might be a chance that the visibility of the continuum is close to 1. However, this peculiar scenario appears very unlikey since the puffed-up rim model has been shown to be well representative of the very close environment of Herbig Ae stars over a large luminosity range (Monnier et al. 2005). Furthermore, the hypothesis of a resolved continuum emission for HD 104237 is strongly supported by its measured accretion rate of $10^{-8}~M_{\odot}$ (Grady et al. 2004). Indeed, Muzerolle et al. (2004) showed that for weak accretion rates ( $\dot{M} < 10^{-7}~M_{\odot}/{\rm yr}$ ), the gas accreting onto the star is optically thin. It therefore does not shield the dust from the stellar radiation and consequently, the star must exhibit an inner region free of dust, large enough to be resolved by the interferometer at the $35~{\rm m}$ baseline.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... project

The structure and members of the AMBER Consortium can be found in the website: http://amber.obs.ujf-grenoble.fr

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... JMMC

The JMMC is a center providing software tools for optical interferometry described at the website: http://www.jmmc.fr

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... Yorick

http://yorick.sourceforge.net

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.