منابع مشابه
The Double-Mode Cepheid V371 Persei Redux
A metallicity of 1⁄2Fe=H 1⁄4 0:05 to 0:40 was derived from four spectra of the peculiar beat Cepheid V371 Per. This conflicts with previous estimates ranging from 0:7 to 1:0 based on the period ratio. It is suggested that the discrepancy may be resolved by assuming near solar metallicity but a low mass. This is in accord with a suggestion by Sandage and Tammann that the AHB3 (or BL Her) stars a...
متن کاملNonlinear Beat Cepheid and RR Lyrae Models
The numerical hydrodynamic modelling of beat Cepheid behavior has been a long standing quest in which purely radiative models had failed consistently. We find that beat pulsations occur naturally when turbulent convection is accounted for in our hydrodynamics code. The development of a relaxation code and of a Floquet stability analysis greatly facilitates the search for and the analysis of bea...
متن کاملThe role of negative buoyancy in convective Cepheid models. Double-mode pulsations revisited
The longstanding problem of modeling double-mode behaviour of classical pulsators was solved with the incorporation of turbulent convection into pulsation hydrocodes. However, the reasons for the computed double-mode behaviour were never clearly identified. In our recent papers (Smolec & Moskalik 2008a,b) we showed that the double-mode behaviour results from the neglect of negative buoyancy eff...
متن کاملTriple - Mode Cepheid Masses
Observations of the light variations of AC Andromedae and TU Cassiopeiae are reviewed. The radial fundamental, first overtone, second overtone, and three nonlinear coupling beat pulsation periods of AC And are presented, confirming the Fitch and Szeidl work. For TU Cas the radial fundamental, first overtone, and several nonlinear coupling beat periods can be found, and a Fourier analysis has co...
متن کاملOn resonant and non-resonant origin of double-mode Cepheid pulsation
Double-mode Cepheid behaviour may arise either from non-resonant or resonant mode interaction. Inclusion of turbulent convection into pulsation codes by Kolláth et al. led to stable double-mode F+1O Cepheid pulsation [1]. However, our recent computations indicate, that these models resulted from incorrect neglect of negative buoyancy effects [2]. Once these effects are taken into account, only ...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 2000
ISSN: 0252-9211
DOI: 10.1017/s0252921100058097