| Summary: | As part of a larger program precise radial velocities (PRVs) have been obtained by useof a hydrogen fluoride (HF) cell over the period 1980 to 1992, for twenty-one dwarf andsubgiant stars (luminosity classes IV and V) together with eleven giants and supergiants(luminosity classes I, II, and III). A typical PRV measurement has an accuracy of
15ms-1.
As part of this thesis a full analysis method has been developed, and applied to, theHF dwarf and subgiant program data, in an effort to find evidence for extra-solar planets.Although no such evidence was found we do find that about one half of the HF programstars show significant secular trends in their radial velocities, which may indicate signalsat periods longer than we are currently sensitive to. Detection limits are set in the formof minimum detectable planetary masses for each of the stars.
Periodicities in the differential equivalent width of the Call infrared triplet line(AEWc„H) data are found for o2 Eri, a Dra, 61 Cyg A, and HR8832 which may result from a stellar cycle, analogous to the Solar cycle. Correlations between the radial velocityand AEWcan data are found for 36 UMa and # Cora. === Science, Faculty of === Physics and Astronomy, Department of === Graduate
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