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Spectral analysis of the B[e] star FS CMa
Kříček, Radek ; Korčáková, Daniela (advisor) ; Mayer, Pavel (referee)
The thesis is dealing with spectral analysis of the B[e] star FS CMa, a prototype of FS CMa stars group. These objects are characterized by huge amount of matter in sourrounding shell which origin is not explained for many years. However, solving this issue could enrich stellar astrophysics by enhanced stellar evolution models. The goal of this thesis is to improve our understanding of FS CMa. We described spectral variability on various time scales and simulated spectra for different forms of the system in HDUST code. On the basis of new obtained spectra we confirmed long-term changes in variability of some spectral features and rapid variability of some spectral lines. We gained an estimate of the gas density. The simulations showed that spectral type of FS CMa is not certain and that the star could be surrounded by extended disk, many stellar radii wide. 1
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Spectral analysis of the B[e] star FS CMa
Kříček, Radek ; Korčáková, Daniela (advisor) ; Mayer, Pavel (referee)
The thesis is dealing with spectral analysis of the B[e] star FS CMa, a prototype of FS CMa stars group. These objects are characterized by huge amount of matter in sourrounding shell which origin is not explained for many years. However, solving this issue could enrich stellar astrophysics by enhanced stellar evolution models. The goal of this thesis is to improve our understanding of FS CMa. We described spectral variability on various time scales and simulated spectra for different forms of the system in HDUST code. On the basis of new obtained spectra we confirmed long-term changes in variability of some spectral features and rapid variability of some spectral lines. We gained an estimate of the gas density. The simulations showed that spectral type of FS CMa is not certain and that the star could be surrounded by extended disk, many stellar radii wide. 1
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Spectroscopy of B[e] star FS CMa
Kříček, Radek ; Korčáková, Daniela (advisor) ; Krtička, Jiří (referee)
B[e] stars are a peculiar group of stars with forbidden emission lines in their spectra. This phenomenon is commonly ascribed as a result of a large shell around the star. FS Canis Majoris (FS CMa) became a prototype of one group of these stars because it was intensively studied in the past. However, in the case of this class of objects current theoretical models of the stellar evolution of a single star are not able to produce such huge amount of circumstellar matter, even if the stellar wind and rapid rotation are included into the calculations. We analysed and rectified some already reduced spectra obtained from 2005 to 2011 at the Astronomical Institute of the Academy of Sciences of the Czech Republic in Ondřejov and at SAAO observatory. Then we focused on the study of short- and long-term time variations of spectral lines in the stellar spectra, measured equivalents widths and radial velocities of the chosen spectral lines and discussed some achieved findings. Especially the short-term time variations of some spectral lines show dynamic processes of the inner star shell.
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