Study of pulsational instabilities in models of δ Scuti pulsators discovered under the Nainital-Cape Survey

Abstract

Under the Nainital-Cape Survey, eight Scuti type pulsators have been discovered with the pulsation periods in the range of several minutes to few hours. In order to understand these observed pulsational variabilities, we have performed non-adiabatic linear stability analyses of these stars having mass in the range of 1 to 3 Mʘ. Several low order pressure modes (p-modes) are found to be unstable where the pulsation pe-riods associated with these unstable modes are in good agreement with the observed periods. Particularly for HD 118660, HD 113878, HD 102480, HD 98851, and HD 25515, we demonstrate that the observed variabilities can be explained with the low order radial p-mode pulsations.