నైరూప్య

Frequency analysis of short periodic Cepheid BD+13 218 as Seen from SMEI Observations

Abdel-Sabour M, Sanad MR, Benday R and Elkholy E

A total of 1848 flux observations of BD+13 218 are obtained by using the Solar Mass Ejection Imager (SMEI) on board of the Coriolis satellite. The data reveal a significant cycle-to-cycle fluctuation in the pulsation period, indicating that classical Cepheid may not be accurate regardless of the specific points used to determine the O-C values. Eddington & Plakidis (1929) methods and random fluctuations in periods were studied. The present detailed O-C residuals for pulsating star BD+13 218 (P=2.8364 day) is studied. Pulsation frequencies and Fourier spectra are presented. By using the empirical relations for stellar structure we determined the parameters of BD+13 218, Teff = 5917.052±145.262,