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The Time Variability Of Spectral Line Asymmetries And Equivalent Widths For The G8 Dwarf Xi Boo A: Evidence For A "Starpatch", Clifford George Toner
The Time Variability Of Spectral Line Asymmetries And Equivalent Widths For The G8 Dwarf Xi Boo A: Evidence For A "Starpatch", Clifford George Toner
Digitized Theses
The chromospherically active G8 dwarf Xi Boo A has been monitored spectroscopically for four observing seasons. A total of 121 high resolution, high signal-to-noise Reticon exposures (representing {dollar}\sim{dollar}300 hours of observing) were obtained at the University of Western Ontario's 1.2 m telescope.;The data were analyzed for variations in the mean line asymmetry, line strength, and line broadening, using a combination of line bisector and Fourier techniques. Systematic variations in all quantities were found, which repeat with a period of 6.43 {dollar}\pm{dollar} 0.01 days. The line broadening variations show no evidence of being magnetic in nature, and there is no evidence …
Abundance And Magnetic Field Geometries Of The Helium-Strong Stars, David Allan Bohlender
Abundance And Magnetic Field Geometries Of The Helium-Strong Stars, David Allan Bohlender
Digitized Theses
High signal-to-noise coude reticon spectra of five helium-strong stars have been obtained in two spectral regions ({dollar}\lambda\lambda{dollar}3980-4160 and {dollar}\lambda\lambda{dollar}4400-4580) at the Canada-France-Hawaii Telescope, Mauna Kea, Hawaii. Phase-resolved sets of spectra have been obtained for the magnetic-variable stars {dollar}\sigma{dollar} Ori E, HD 37776, and HD 64740. Additional observations have also been made of the sharp-lined helium-strong stars HD 58260 and {dollar}\delta{dollar} Ori C. These data, and additional Zeeman analyzer observations, have been used in an attempt to determine the magnetic field geometries and abundance distributions of the program stars. The models have been obtained by use of a line synthesis program …