Niu Jia-Shu, Fu Jian-Ning, Yang Xiao-Hu, Zong Wei-Kai
Time-series photometric observations were made for the SX Phoenicis star AE UMa between 2009 and 2012 at the Xinglong Station of National Astronomical Observatories of China (NAOC). No additional frequencies were detected. With the frequency analysis of the light curves, we confirmed the fundamental and the first overtone frequencies as $f_{0} = 11.62560\ cd^{-1}$ and $f_{1} = 15.03124\ cd^{-1}$. Additionally, we also got 37 frequencies which are the harmoics and the combinations of the fundamental and first overtone frequency. 25 of these frequencies are newly detected. The O-C diagram, produced from 84 newly determined times of maximum light combined with those derived from the literature, reveals a continuous period variation with the rate of $(1/P_{0})(dP_{0}/dt) = 5.36(84) \times 10^{-9}\ yr^{-1}$ and $(1/P_{1})(dP_{1}/dt) = -2.78(37) \times 10^{-8}\ yr^{-1}$. Theoretical rates of period change due to the stellar evolution were calculated with a modeling code. Constraint of the variation of $P_{1}$ allows us to determine the star's location on the H-R diagram precisely. The result shows that the observed rate of period change is fully consistant with period change caused by the evolutionary behavior predicted by standard theoretical model.
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http://arxiv.org/abs/1304.3772
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