Context :

Aims : Procyon A , a bright F5 IV-V Sun-like star , is justifiably regarded as a prime asteroseismological target .
This star was repeatedly observed by MOST , a specialized microsatellite providing long-term , non-interrupted broadband photometry of bright targets .
So far , the widely anticipated p modes eluded direct photometric detection , though numerous independent approaches hinted for the presence of signals in the f \sim 0.5 - 1.5 mHz range .

Methods : Implementation of an alternative approach in data processing , as well as combination of the MOST data from 2004 and 2005 ( 264 189 measurements in total ) helps to reduce the instrumental noise affecting previous reductions , bringing the 3 \sigma detection limit down to \sim 5.5 part-per-million in the f = 0.8 - 1.2 mHz range .

Results : This enables to cross-identifiy 16 p-mode frequencies ( though not their degrees ) which were previously detected via high-precision radial velocity measurements , and provides an estimate of the large spacing , \delta \nu = 0.0540 mHz at f \sim 1 mHz .
The relatively low average amplitude of the detected modes , a = 5.8 \pm 0.6 ppm , closely matches the amplitudes inferred from the ground-based spectroscopy and upper limits projected from WIRE photometry .
This also explains why such low-amplitude signals eluded the direct-detection approach which exclusively relied on the MOST 2004 ( or 2005 ) data processed by a standard pipeline .

Conclusions :