J/A+A/341/818 J/A+A/341/818 s-Cepheid velocity curves F Kienzle P Moskalik D Bersier F Pont Astron. Astrophys. 341 818 1999 1999A&A...341..818K J/A+AS/108/9 : Cepheids fundamental parameters I. (Bersier+, 1994) J/A+AS/108/25 : Cepeheids fundamental parameters II. (Bersier+, 1994) J/A+A/305/551 : Chemical composition of the s-Cepheids (Andrievsky+, 1996) Krzyt, T., Moskalik, P., Gorynya, et al., 1999, (in preparation) Radial velocities Stars, variable Cepheids stars: oscillations techniques: radial velocities The light curves of the first overtone Pop. I Cepheids (s-Cepheids) show a discontinuity in their {phi}_21_ vs. P diagram, near P=3.2day. This feature, commonly attributed to the 2:1 resonance between the first and the fourth overtones ({omega}_4_~2{omega}_1_), is not reproduced by the hydrodynamical models. With the goal of reexamining the resonance hypothesis, we have obtained new CORAVEL radial velocity curves for 14 overtone Cepheids. Together with 10 objects of Krzyt et al. (1999, in prep.), the combined sample covers the whole range of overtone Cepheid periods. The velocity Fourier parameters display a strong characteristic resonant behavior. In striking contrast to photometric ones, they vary smoothly with the pulsation period and show no jump at 3.2day. The existing radiative hydrodynamical models match the velocity parameters very well. The center of the {omega}_4_=2{omega}_1_ resonance is estimated to occur at Pr=4.58+/-0.04day, i.e. at a period considerably longer than previously assumed (3.2day). We identify two new members of the s-Cepheid group: MY Pup and V440 Per.

STAR Star name according to GCVS --- Period Period d e_Period One sigma error Period d M Number of data points --- N Number of harmonics fitted --- sigma RMS of the residuals km/s A0 Gamma velocity km/s e_A0 One sigma error gamma velocity km/s A1 Amplitude A1 km/s e_A1 One sigma error amplitude A1 km/s R21 Amplitude ratio A2/A1 --- e_R21 One sigma error amplitude ratio R21 --- f21 Phase shift phi2-2*phi1 --- e_f21 One sigma error phase shift f21 --- R31 =-9.999 Amplitude ratio A3/A1 --- e_R31 =-9.999 One sigma error amplitude ratio R31 --- f31 =-9.999 Phase shift phi3-3*phi1 --- e_f31 =-9.999 One sigma error phase shift f31 --- R41 =-9.999 Amplitude ratio A4/A1 --- e_R41 =-9.999 One sigma error amplitude ratio R41 --- f41 =-9.999 Phase shift phi4-4*phi1 --- e_f41 =-9.999 One sigma error phase shift f41 --- R51 =-9.999 Amplitude ratio A5/A1 --- e_R51 =-9.999 One sigma error amplitude ratio R51 --- f51 =-9.999 Phase shift phi5-5*phi1 --- e_f51 =-9.999 One sigma error phase shift f51 --- RAh Right Ascension J2000 (hours) number=1 columns added at CDS, values from SIMBAD data-base. h RAm Right Ascension J2000 (minutes) number=1 columns added at CDS, values from SIMBAD data-base. min RAs Right Ascension J2000 (seconds) number=1 columns added at CDS, values from SIMBAD data-base. s DE- Declination J2000 (sign) number=1 columns added at CDS, values from SIMBAD data-base. --- DEd Declination J2000 (degrees) number=1 columns added at CDS, values from SIMBAD data-base. deg DEm Declination J2000 (minutes) number=1 columns added at CDS, values from SIMBAD data-base. arcmin DEs Declination J2000 (seconds) number=1 columns added at CDS, values from SIMBAD data-base. arcsec STAR Star name according to GCVS --- HJD Heliocentric julian day d RV Radial velocity km/s e_RV One sigma error km/s Patricia Bauer CDS 1998Oct23Francesco Kienzle <Francesco.Kienzle@obs.unige.ch> J_A+A_341_818.xml