Radial velocity variations in pulsating Ap stars - III. The discovery of 16.21-min oscillations in β CrB

We present the analysis of 3 h of a rapid time series of precise stellar radial velocity (RV) measurements (σ= 4.5 m s^-1) of the cool Ap star β CrB. The integrated RV measurements spanning the wavelength interval 5000-6000 Åshow significant variations (false alarm probability = 10^-5) with a period of 16.21 min (ν= 1028.17 μHz) and an amplitude of 3.54 +/- 0.56 m s^-1. The RV measured over a much narrower wavelength interval reveals one spectral feature at λ6272.0 Åpulsating with the same 16.21-min period and an amplitude of 138 +/- 23 m s^-1. These observations establish β CrB to be a low-amplitude rapidly oscillating Ap star.