  We present here the detection of a brown dwarf orbiting the A9V star
HD180777. The radial velocity measurements, obtained with the ELODIE echelle
spectrograph at the Haute-Provence Observatory, show a main variation with a
period of 28.4 days. Assuming a primary mass of 1.7 Mo, the best Keplerian fit
to the data leads to a minimum mass of 25 MJup for the companion (the true mass
could be significantly higher). We also show that, after substraction of the
Keplerian solution from the radial velocity measurements, the residual radial
velocities are related to phenomena intrinsic to the star, namely pulsations
with typical periods of Gamma Dor stars. These results show that in some cases,
it is possible to disentangle radial velocity variations due to a low mass
companion from variations intrinsic to the observed star.
