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Mesures de vitesses radiales. VIII. Accompagnement AU sol DU programme d'observation DU satellite HIPPARCOS
We publish 1879 radial velocities of stars distributed in 105 fields of4^{\circ} \times 4^{\circ}. We continue the PPO series \cite[(Fehrenbachet al. 1987;]{Feh87} \cite[Duflot et al. 1990, 1992 and 1995),]{Du90}using the Fehrenbach objective prism method. Table 1 only available inelectronic form at CDS via to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| On the period variation of the Delta Scurti star VZ CANCRI
New photometric photometry and new times of maximum light are reportedfor the delta Scuti-type star VZ Cancri. Times of maximum lightavailable for the last five decades have been studied. The times ofmaximum from the last decade, however, indicate that the period has notbeen steadily increasing as believed until now. To allow for thisdiscrepancy several interpretations of the O-C diagram are discussed.However, the scatter in the (O-C) residuals is large and it is difficultto favor a case between a sloping linear fit and a sinusoidal fit. Theformer indicates that the main period needs to be revised and apredicted value of 0.17836365 days is obtained. The later suggests thepresence of an unseen companion whose nature and implications arebriefly discussed. In either case it can be concluded that VZ Cancri isnot undergoing any secular period variation. Other possibilities likeabrupt period changes and long-term effects of nonlinear combinations ofshort frequencies are discussed but found unrealistic.
| Observations and a new interpretation for the Delta Scuti variable star VZ CANCRI
The pulsation characteristics of VZ Cnc were examined, together with thepossibility of He settling in the stellar envelope. Data were gatheredwith the 40 cm Tortugas telescope and photometry system and includedcomparison figures in UBV for HD 73938 and HD 74308. The observationswere made in February-April 1983 and were subjected to Fouriertransforms and least squares analysis. Light variations in VZ Cnc wereattributed to coupling between two frequencies, a condition whichproduced higher amplitudes than either component alone. A stable periodratio of 0.80 was calculated, with the main pulsational energyconcentrated in the first frequency, 5.6 cycles/day. The secondfrequency exhibited 7.0 cycles/day. The period ratio supports a Hedepletion process. A stellar temperature of 7500 K would eliminate thenecessity of He settling as part of the model and confirm the presenceof 1H and 2H, rather than fundamental, pulsation modes.
| The Cluster-Type Variable VZ CANCRI.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1955ApJ...121..690F&db_key=AST
| The Cluster-Type Cepheid HD 73857
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