双星与变星研究组知识库

DE Lac is a high-amplitude delta Scuti variable with a period of 0.253694 days. New CCD photometric monitoring of DE Lac was carried out on 2013 December 18 and 2014 January 5, by using the 1.0-m reflecting telescope at Yunnan Observatories. Photometric observations of DE Lac were also obtained by using the 85-cm telescope at Xinglong Station of National Astronomical Observatory. By using a few new determined times of maximum light together with those collected from the literature, the period changes in Observed-Calculated (O - C) diagram are analyzed. We discover that the pulsating period of DE Lac is increasing continuously at a rate of (P) over dot = + 3.7 x 10(-8) days/year. It is compatible with the prediction from the stellar evolution model calculations. Meanwhile, we collect other delta Scuti stars that have exhibited period changes.