Searching for solar-like oscillations in the δ Scuti star ρ Puppis ⋆

Despite the shallow convective envelopes ofScuti pulsators, solar-like oscilla- tions are theoretically predicted to be excited in those stars as well. To search for such stochastic oscillations we organised a spectroscopic multi-site campaign for the bright, metal-richSct starPuppis. We obtained a total of 2763 high-resolution spectra using four telescopes. We discuss the reduction and analysis with the iodine cell technique, developed for searching for low-amplitude radial velocity variations, in the presence of high-amplitude variability. Furthermore, we have determined the angular diameter ofPuppis to be 1.68 ± 0.03 mas, translating into a radius of 3.52 ± 0.07 R⊙. Using this value, the frequency of maximum power of possible solar-like oscillations, is expected at � 43±2 cd −1 (498±23 µHz). The dominantScuti-type pulsation mode ofPuppis is known to be the radial fundamental mode which al- lows us to determine the mean density of the star, and therefore an expected large frequency separation of 2.73 cd −1 (31.6 µHz). We conclude that 1) the radial velocity amplitudes of theScuti pulsations are different for different spectral lines; 2) we can exclude solar-like oscillations to be present inPuppis with an amplitude per radial mode larger than 0.5 ms −1 .