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Radiation in stellar winds. Resonance line formation in inhomogeneous hot star winds
Šurlan, Brankica ; Kubát, Jiří (advisor) ; Krtička, Jiří (referee) ; Róžaňska, Agata (referee)
Title: Radiation in stellar winds. Resonance line formation in inhomogeneous hot star winds Author: M.Sc. Brankica Šurlan Department: Astronomical Institute of the Academy of Sciences of the Czech Republic Supervisor: RNDr. Jiří Kubát, CSc., Astronomical Institute of the Academy of Sciences of the Czech Republic Abstract: To incorporate the three-dimensional (3-D) nature of stellar wind clump- ing into radiative transfer calculations, in this thesis a newly developed full 3-D Monte Carlo radiative transfer code for inhomogeneous expanding stellar winds is presented and used to investigate how different model parameters influence reso- nance line formation. Realistic 3-D models that describe the dense as well as the rarefied wind components are used to model the formation of resonance lines in a clumped stellar wind. Non-monotonic velocity fields are accounted for as well. It is shown that the 3-D density and velocity wind inhomogeneities have very strong impact on the resonance line formation. The models show that the line opacity is lower for a larger clump separation and shallower velocity gradients within the clumps. They also demonstrate that to obtain empirically correct mass-loss rates from UV resonance lines, wind clumping and its 3-D nature must be taken into account. 1
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Radiation in stellar winds. Resonance line formation in inhomogeneous hot star winds
Šurlan, Brankica ; Kubát, Jiří (advisor) ; Krtička, Jiří (referee) ; Róžaňska, Agata (referee)
Title: Radiation in stellar winds. Resonance line formation in inhomogeneous hot star winds Author: M.Sc. Brankica Šurlan Department: Astronomical Institute of the Academy of Sciences of the Czech Republic Supervisor: RNDr. Jiří Kubát, CSc., Astronomical Institute of the Academy of Sciences of the Czech Republic Abstract: To incorporate the three-dimensional (3-D) nature of stellar wind clump- ing into radiative transfer calculations, in this thesis a newly developed full 3-D Monte Carlo radiative transfer code for inhomogeneous expanding stellar winds is presented and used to investigate how different model parameters influence reso- nance line formation. Realistic 3-D models that describe the dense as well as the rarefied wind components are used to model the formation of resonance lines in a clumped stellar wind. Non-monotonic velocity fields are accounted for as well. It is shown that the 3-D density and velocity wind inhomogeneities have very strong impact on the resonance line formation. The models show that the line opacity is lower for a larger clump separation and shallower velocity gradients within the clumps. They also demonstrate that to obtain empirically correct mass-loss rates from UV resonance lines, wind clumping and its 3-D nature must be taken into account. 1
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Studium atmosfér Be hvězd
Sokolovičová, Júlia ; Kubát, Jiří (advisor) ; Mayer, Pavel (referee)
Be stars are a group of hot, massive, emission-line stars characterized by intense radiatively-driven stellar wind and extremely rapid rotation. The typical emission in the Balmer series arises in a thin equatorial disc around the star. The detailed structure and most of all origin of the disc are still unknown. The aim of this thesis is to give a thorough review of the main directions of research into the eld. We describe observational features that set Be stars apart from the rest of the B spectral class: Balmer emission, linear polarization, infrared excess and superionized resonance lines in the far UV range; also main physical characteristics of the underlying star, and variability. We discuss the so-called Be phenomenon - the unknown mechanism creating the emission-producing circumstellar disc in Be stars, and providine an overview of the most successful models attempting to explain the Be phenomenon. Finally we discuss the rotation law of the disc and its importance in placing a physical constraint on possible models for Be stars, and apply one of the examined rotation parameter nding methods.
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Social Services in the Old Age and in case of Diseases
Šarochová, Miloslava ; Sedláková, Jaroslava (advisor) ; Kubát, Jiří (referee)
My work evaluates the impacts of Law of social services on the care of retired people, taking the needs of elderly people in respect. A greater attention will be paid to the support called "care allowance ". An internal part of this work is the analysis of costs of individual family members incurred on the care of the retired person, including the costs connected to the care at home compared to costs of the stay in a social or health facility.
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Financial Sustainability of an Unpaid Voluntary Project
Venkrbcová, Martina ; Sedláková, Jaroslava (advisor) ; Kubát, Jiří (referee)
The work deals with the legislative background and the financial sustainability of voluntary projects in the social services. In the introductory part are defined by basic concepts that relate to volunteering and social services. Further funding options are described volunteer programs. In the practical part is outlined a budget for the volunteer project at a retirement home in Jindrichuv Hradec. They are designed specific funding opportunities for this project and model of working with volunteers. An integral part is a questionnaire survey, which took place between staff and clients retirement home.
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