We report evidence for the granulation signal in the star Procyon A , based on two photometric time series from the star tracker on the WIRE satellite .
The power spectra show evidence of excess power around 1 mHz , consistent with the detection of p-modes reported from radial velocity measurements .
We see a significant increase in the noise level below 3 mHz , which we interpret as the granulation signal .
We have made a large set of numerical simulations to constrain the amplitude and timescale of the granulation signal and the amplitude of the oscillations .
We find that the timescale for granulation is \Gamma _ { gran } = 750 \pm 200 s , the granulation amplitude is 1.8 \pm 0.3 times solar , and the amplitude of the p-modes is 8 \pm 3 ppm .
We found the distribution of peak heights in the observed power spectra to be consistent with that expected from p-mode oscillations .
However , the quality of the data is not sufficient to measure the large separation or detect a comb-like structure , as seen in the p-modes of the Sun .
Comparison with the recent negative result from the MOST satellite reveal that the MOST data must have an additional noise source that prevented the detection of oscillations .