Class: ClassicalCepheid

Classical Cepheid (delta Cep type)

•owl:Thing
        •AstrObject
                •VariableObject
                        •PulsatingStar
                                •ClassicalCepheid

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hasHighMeasurement SOME Mass
PulsatingStar

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misc:descriptionThese are the classical cepheids, or Delta Cep-type variables. Comparatively young objects that have left the main sequence and evolved into the instability strip of the Hertzsprung-Russell (H-R) diagram, they obey the well-known Cepheid period-luminosity relation and belong to the young disk population. Delta Cep stars are present in open clusters. They display a certain relation between the shapes of their light curves and their periods. Sub-type: - These are Delta Cep variables having light amplitudes <0.5 mag in V (<0.7 mag in B) and almost symmetrical light curves (M-m approx. 0.4 - 0.5 periods); as a rule, their periods do not exceed 7 days. They are probably first-overtone pulsators and/or are in the first transition across the instability strip after leaving the main sequence (SU Cas). Traditionally, both Delta Cep and W Vir stars are quite often called Cepheids because it is often impossible to discriminate between them on the basis of the light curves for periods in the range 3 - 10 days. However, these are distinct groups of entirely different objects in different evolutionary stages. One of the significant spectral differences between W Vir stars and Cepheids is the presence, during a certain phase interval, of hydrogen-line emission in the former and of Ca II H and K emission in the latter.
simbad:namedeltaCep
simbad:shortCodecC*
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