Abstract

The reduction of all the available photometry for the Cepheid ET Vul has allowed its \(O-C\) diagram spanning a time interval of 130 years to be constructed. This has made it possible to calculate for the first time the rate of evolutionary decrease in the period, \(dP/dt=-426.5(\pm{29.7})\) s yr\({}^{-1}\), in agreement with the results of model calculations for the second crossing of the instability strip. The pulsation stability test proposed by Lombard and Koen has confirmed that the evolutionary change in the period is real.

中文翻译：

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寻找造父变星外阴时期的进化变化

摘要

对造父变星ET Vul的所有可用光度学的减少，使得它的\（OC \）图跨越了130年的时间间隔得以构建。这样就可以首次计算出该时期\（dP / dt = -426.5（\ pm {29.7}）\） s yr \（{} ^ {-1} \），与不稳定性带第二次穿越的模型计算结果一致。Lombard和Koen提出的脉动稳定性测试已证实该时期的演化变化是真实的。