Astron. Astrophys. 363, 601-604 (2000)

5. Conclusions

Nonlinear pulsation models for long period Cepheids in Magellanic Clouds have been compared with observations in terms of weighted phases and amplitude ratios of Fourier components of light and radial velocity curves. While the longer P ( d) Cepheids appear unsensitive to the adopted M-L relation, for shorter P Cepheids it seems that an overluminous relation gives better results than a full overshooting-type relation. The results indicate also that regular limit cycles of more massive models depend on the metal content, in the sense that more massive models can have a stable limit cycle for lower metal content. The nonlinear P of such metal poor models tends to be much longer than the LNA one, and this can explain the flattening of the PL relation for d, which is observed in metal poor galaxies. Finally, the difficulties of radiative models in reproducing the observed features of resonance effects on the light curves are confirmed.

© European Southern Observatory (ESO) 2000

Online publication: December 11, 2000
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