Revised masses for the double-mode and bump Cepheids. [Rotation, helium- or metal-rich-layer]

Journal Article · Wed Jun 15 00:00:00 EDT 1977 · Astrophys. J., Lett.; (United States)

DOI:https://doi.org/10.1086/182457· OSTI ID:7215227

Cox, A N; Deupree, R G; King, D S; Hodson, S W

We consider Population I Cepheids with two pulsation modes and those with a bump in the light and velocity curves. Model envelopes for these Cepheids have been altered in several ways in an attempt in remove the discrepancy between masses predicted from the evolution theory mass-luminosity relation an th masses predicted from pulsation theory. One of these ways, the inclusion of rotation, does not change the period ratio of the first overtone mode to the fundamental mode enough to resolve this mass discrepancy. Another way, the inclusion of a helium- (or metal-) rich layer mixed by convection and pulsation between the stellar surface and 70,000 K decreases this period ratio appreciably. The ratio of the second overtone period to the fundamental period is also reduced with this structure. The masses of the double-mode Cepheids U TrA and V367 Sct and the bump Cepheids U Sgr and ..beta.. Dor are found to be much closer to the masses derived from stellar evolution theory.

• Research Organization: Theoretical Division, University of California, Los Alamos Scientific Laboratory
• OSTI ID: 7215227
• Journal Information: Astrophys. J., Lett.; (United States), Vol. 214:3
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CEPHEIDS
MASS
VARIABLE STARS
CONVECTION
ENERGY SPECTRA
PULSATIONS
ROTATION
STAR EVOLUTION
STAR MODELS
VARIATIONS
ENERGY TRANSFER
HEAT TRANSFER
MATHEMATICAL MODELS
MOTION
SPECTRA
STARS
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources