Studying the Variability of Dying Stars

In this project, we are observing and analyzing the light variability in a class of dying stars. This involves observing then on clear nights, primarily at the Valparaiso University Observatory but also including a few nights at the SARA Telescope at Kitt Peak National Observatory in Arizona. Thus far this summer we have observed for 25 nights and we observed 31 stars. Some of them we observed on every clear night and others we observed once or twice a week. We are analyzing a subset of 18 of these. We find that they have varied in light by 12 to 74% over the four years of observations. So far, periods have been found for 8 out of 18 objects, and they range from 50 to 315 days, based on the data collected before May 2012. These variations are due primarily to the pulsation of the stars. The goal is to find the amplitude and period of the variations; these can be used to investigate the internal structure of the stars