A New Method for the Definition of s-Cepheids
Session 55 -- Pulsating Variables/Stellar Models
Display presentation, Thursday, 2, 1994, 9:20-6:30

## [55.06] A New Method for the Definition of s-Cepheids

S.M.Morgan (Univ. N. Iowa)

A new method of delineating sinusoidal or s-Cepheids is presented. The method uses the values of $<~V~>$ (the average intensity), $\overline{V}$ (the average magnitude), and $V_{median}$ (the value of the median magnitude). Fourier coefficient data from galactic Cepheids is used to derive these terms in the $V$ band and the differences between the various terms show systematic trends with increasing period. The Cepheids can be easily grouped into 3 divisions - short period s-Cepheids, intermediate period Cepheids ($P<9$ days), and long period Cepheids ($P>9$ days). The Hertzsprung progression has vitually no effect on the difference values over the various period ranges. Cepheids previously designated as s-Cepheids by others are compared to those found using the method outlined. The method is also applied to Cepheids in the Small Magellanic Cloud to examine its suitability as a pulsation mode discriminator.