Irregular amplitude variations and another abrupt period change in the δ Scuti star V 1162 Ori^*

¹ University of Brussels (VUB), Pleinlaan 2, 1050 Brussels, Belgium
² South African Astronomical Observatory, PO Box 9, Observatory 7935, South Africa
³ Department of Astrophysics, Astronomy and Mechanics, University of Athens, 157 84 Zografos, Athens, Greece
⁴ Department of Physics, University of the North-West, Private Bag X2046, Mmabatho 2735, South Africa
⁵ Beersel Hills Observatory, Belgium

Corresponding author: T. Arentoft, tarentof@vub.ac.be

Received: 29 August 2001
Accepted: 6 September 2001

Abstract

We report that the intermediate amplitude δ Scuti star V 1162 Ori has changed its main pulsational period in the course of the year 2000. This new period change falls in a sequence of period changes observed during the last 5 years. While the average amplitude value of all our new data, 63 mmag, fits a cyclic amplitude variation suggested by Arentoft et al. (2001), splitting the data up in smaller subsets discloses significant deviations from regularity, with stretches of constant amplitude during short intervals of time. The new data show that the amplitude of one of the secondary frequencies, f₂, has in 3 years dropped from more than 3 mmag to now about 1 mmag, and that the previously obtained f₅ probably is a 1 d^-1 alias of the real frequency. We present the newly acquired times of minimum and maximum light as support for subsequent observing campaigns.