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Paper: Cepheid Masses: FUSE Observations of S Mus
Volume: 310, Variable Stars in the Local Group (IAU Colloquium 193)
Page: 377
Authors: Remage Evans, N.; Massa, D.; Fullerton, A.; Sonneborn, G.; Iping, R.
Abstract: S Mus if the Cepheid with the hottest known companion. As a benefit, the large ultraviolet flux made it the only Cepheid companion for which the velocity amplitude could be measured with the echelle mode of the HST GHRS. Unfortunately, the high temperature is difficult to constrain at wavelengths longer than 1200 Å because of the degeneracy between temperature and reddening. We have now obtained a FUSE spectrum in order to determine the temperature of the companion better. We have identified two regions which are temperature sensitive near 16,000 K, but are relatively unaffected by H2 absorbtion (940 Å, and the Ly β wings). By comparing S Mus B with other FUSE spectra, we have determined a temperature of 17,000 K. The resultant Cepheid mass is 6.0 ± 0.4 Solar masses.
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