A radial velocity search for p-mode pulsations in eta Bootis

The subgiant eta Boo (G5 IV) has been reported to show p-mode pulsations, as evidenced by variations in the equivalent width of its hydrogen Balmer lines (reported by Kjeldsen et al.). In an attempt to confirm this report, we observed eta Boo's radial velocity with the AFOE spectrograph for a total of 22 hours spread over seven successive nights in 1995 March. We find no evidence for the presence of excess power at the frequencies reported by Kjeldsen et al.; our upper limit corresponds to typical mode amplitudes of 0.5 m s(-1), about 3 times smaller than the velocity amplitudes they inferred. Signals with amplitudes larger than 0.5 m s(-1) may be present at other frequencies within the 0-1000 mu Hz range, but evidence for such signals is scanty, and typical mode amplitudes greater than 1.5 m s(-1) are clearly inconsistent with our observations.