A Search for global acoustic on α1 Cen and β Hyi

Time-series observations of the radial velocities of β Hyi (HR 98, G2 IV) and α¹ Cen (HR 5459, G2 V) have been examined for the periodicities expected from global p-mode oscillations. For α¹ Cen, the upper limit on the amplitude of any coherent oscillation in the 2 – 4 mHz band is 0.5 –0.6 m s⁻¹. There is evidence of periodicity in the power spectrum, with splitting $$\Delta_{\upsilon0}/2\approx53-55$$ μHz. For β Hyi, an upper limit of 1.5 – 2.0 m s⁻¹ can be placed on the amplitude of any oscillation in the expected period range. While we do not claim to have detected unambiguousevidence of p-mode oscillations on α¹ Cen or β Hyi, we have placed significant upper limits onsuch oscillations as might exist. We have also demonstrated the feasibility of using coudé spectroscopy to detect oscillations with amplitudes comparable to those on the Sun.