Sökning: "Stars: fundamental parameters"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden Stars: fundamental parameters.

  1. 1. Solar Type Stars as Calibrators : A Photometric and Spectroscopic Study on the Atmospheric Properties of Late-type Stars

    Författare :Anna Önehag; Ulrike Heiter; Andreas Korn; Bengt Gustafsson; Frank Grundahl; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stars: atmospheres; stars: late-type; techniques: photometric; stars: abundances; techniques: spectroscopic; Astronomy; Astronomi;

    Sammanfattning : Detailed knowledge of solar-type stars is essential in the understanding of the evolutionary past, presence and future of the Sun as well as the formation of its planetary system. Moreover, solar-type stars are of key significance for the study of the evolution of the Galaxy. The ages of solar-type stars map the full galactic evolution. LÄS MER

  3. 2. Photometry of Resolved Stellar Populations in Local Group Galaxies

    Författare :Daniel Faria; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomi; Astronomy; Local Group; Galaxy: halo; Galaxies: dwarf; Galaxy: stellar content; Galaxies: photometry; Techniques: photometric; Stars: fundamental parameters;

    Sammanfattning : This thesis presents results from two projects using photometric observations to investigate stellar populations in Local Group galaxies. In the first project, Strömgren photometry is used to study stellar populations in dwarf spheroidal galaxies. LÄS MER

  4. 3. Metallicity determination of M dwarfs

    Författare :Sara Lindgren; Ulrike Heiter; Ansgar Reiners; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stars: low mass - stars: abundances; fundamental parameters - technique: spectroscopic; photometric - planets and satellites: formation;

    Sammanfattning : M dwarfs constitute around 70% of all stars in the local Galaxy. Their multitude together with their long main-sequence lifetimes make them important for studies of global properties of the Galaxy such as the initial mass function or the structure and kinematics of stellar populations. LÄS MER

  5. 4. Exploring the Chemical Evolution of Globular Clusters and their Stars : Observational Constraints on Atomic Diffusion and Cluster Pollution in NGC 6752 and M4

    Författare :Pieter Gruyters; Andreas Korn; Piercarlo Bonifacio; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stars: abundances – stars: atmospheres – stars: fundamental parameters – globular clusters: individual: NGC 6752 and M4 – techniques: spectroscopic; Astronomy with specialization in Astrophysics; Astronomi med intiktning mot astrofysik;

    Sammanfattning : Through the cosmic matter cycle, the chemical evolution of the Milky Way is imprinted in the elemental abundance patterns of late-type stars (spectral types F to K). Due to their long lifetimes ( 1 Hubble time), these stars are of particular importance when it comes to studying the build-up of elements during the early times of our Galaxy. LÄS MER

  7. 5. Chemodynamics in Star-Forming Molecular Clouds

    Författare :Chia-Jung Hsu; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stars: formation; hydrodynamics; methods: numerical; ISM: clouds; astrochemistry;

    Sammanfattning : Stars are fundamental building blocks of galaxies. However, the answers to many basic questions about their formation remain elusive. There is no consensus on a theory that can predict the rate of star formation, its clustering properties, and the conditions needed for massive stars to be born. LÄS MER