Sökning: "kosmisk kemi"
Visar resultat 11 - 15 av 19 avhandlingar innehållade orden kosmisk kemi.
11. Spectral Analysis of Neutron Capture Elements in the Laboratory and Stars
Sammanfattning : The pedigree of the elements heavier than iron is a vital question in the history and evolution of our galaxy. The elements up to and including those of the iron group are produced mainly through fusion processes within stars, giving the stars their energy. LÄS MER
12. Radial Velocities Without Spectroscopy -Astrometric determination of stellar radial motion
Sammanfattning : This work demonstrates the determination of absolute stellar radial velocities from geometrical principles, i.e. using astrometry. Such `astrometric radial velocities' are obtained independently of spectroscopic information. LÄS MER
13. Atomic Influences in Stellar Spectroscopy
Sammanfattning : This thesis is a description of how knowledge of atomic physics can be used in a stellar spectrum analysis. Stellar investigations are spectroscopically performed based on wavelengths, intensities and spectral line structure. LÄS MER
14. Laboratory and stellar spectroscopy of the complex ions Fe+, Mo+, Th+ and U+
Sammanfattning : The new generation of high resolution astronomical instruments such as the Hubble Space Telescope (HST) or the Very Large Telescope (VLT) has renewed the demand for accurate atomic parameters like wavelengths, oscillator strengths and line profiles accompanied by reliable uncertainty estimates. Fourier transform spectroscopy has proven to be a powerful tool when measuring these parameters. LÄS MER
15. Studies of Double and Multiple Stars Using Space Astrometry
Sammanfattning : This thesis introduces and summarizes four papers dealing with the study of double and multiple stars using space astrometry. The introduction gives a brief review of the role of binary observations in various fields of astronomy --- star formation, stellar masses and the mass-luminosity relation, initial mass function, detection of sub-stellar mass companions. LÄS MER