- 學位論文
The Taiwan Automated Telescope Network and the Study of Pulsational Mode Properties of V830 Her and HD 163032.
摘要
The Taiwan Automated Telescope (TAT) Network is a global ground-based network of identical and fully automated telescopes dedicated to the photometric measurements of stars. These telescopes are located at appropriate longitudes around the world to reduce diurnal gaps and to provide long data set. Here, we present the current status of the TAT Network and the improvements of the system carried out in this thesis. We use the TAT network to measure photometric pulsations of two low-amplitude Delta Scuti stars: V830 Her and HD 163032. The data are obtained from two stations of the network, Teide and Maidanak observatories, for four consecutive years (2008-2011). The data used in the study span 1452 hours for V830~Her and 1040 hours for HD~163032. Several new analysis methods developed in this study are used to reduce the noise in measured light curves and improve the precision of measured mode parameters. The temporal variability of mode parameters is of importance in physics of pulsation, although its theoretical study on low-amplitude Delta Scuti is in a preliminary stage. The long TAT data for specific targets allow us to study the temporal variabilities of mode frequency, amplitude, and phase. For the detection of mode frequencies, several criteria are used to discriminate spurious frequencies. Fourteen and four frequencies are convincingly detected for V830~Her and HD~163032, respectively. The year-to-year mode variabilities found in this study are small and random, and we believe that they are measurement errors instead of mode parameter variabilities. These measurement errors provide an upper limit for the yearly variability of mode parameters. The small upper limit for mode phase variability suggests that the pulsational modes detected here have life time longer than the observational period, four years.