A 10-night asteroseismic observation programme has been conducted in January 2004 with the spectrometer harps at the ES0 3.6-m telescope .
The selected target , the 6th magnitude F5V star HD 49933 , was chosen among the prime candidates of corot , the European space mission dedicated to characterize stellar oscillations mode with high precision photometry measurements .
This star shows important line profiles variations , indicating a surprisingly high activity with respect to its low rotation rate .
However , with the help of tools developed for disentangling the signatures of activity and oscillations , we are able to observe its oscillation spectrum in the frequency range [ 1.2 , 2.2 mHz ] .
We measure the large separation ( 88.7 \pm 0.4 \mu Hz ) and the maximum amplitude ( around 0.4 \pm 0.1 m s ^ { -1 } rms ) , respectively in agreement and marginal agreement with the predicted values .