Frequency variability in the rapidly oscillating AP star HR 3831: three more years of monitoring

We present 147 h of high-speed photometric observations of HR 3831 obtained on 125 nights in 1993, 1994, 1995 and 1996. In an ongoing programme, we monitor the pulsation of this star for 1 h on each possible night from November through June to determine its pulsation phase. We then use those pulsation phases to study its frequency variability. We show the character of that frequency variability in...