Sökning: "Stellar ages"

Visar resultat 1 - 5 av 16 avhandlingar innehållade orden Stellar ages.

1. 1. Stellar Ages for Galactic Archaeology : Methods and Applications

   Författare :Christian Sahlholdt; Astronomi - Genomgår omorganisation; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Galaxy : formation; Stellar ages; Milky Way Galaxy; Low mass stars; Galaxy : disc; Galaxy : evolution; Fysicumarkivet A:2021:Sahlholdt;

   Sammanfattning : Galactic Archaeology is the study of the formation and evolution of the Milky Way through the properties of stars and stellar populations. The combination of stellar ages, chemical compositions, positions, and velocities can reveal the history of star formation and chemical enrichment in different regions of the Galaxy. LÄS MER

3. 2. Characterising Young Stellar Binaries

   Författare :Per Calissendorff; Markus Janson; Eric Stempels; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Binaries; stellar ages; multiplicity; Astronomy; astronomi;

   Sammanfattning : Stars are dispersed all over the sky within our Galaxy, appearing in large varieties of ages and sizes. How- ever, estimating said traits proves not to always be trivial, but certain circumstances allow us to probe the characteristics of stellar binaries. LÄS MER

4. 3. Determination of stellar ages and star formation histories - a Bayesian approach With an application to nearby F and G stars

   Författare :Bjarne Rosenkilde Jørgensen; Astronomi - Genomgår omorganisation; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomi; Astronomy; Galaxy evolution; Statistical methods; Stellar evolution; Data analysis;

   Sammanfattning : In order to understand the formation and evolution of the Galaxy it is imperative to know when different components formed. This means at the most basic level that we need to know the ages of stars. The present work demonstrates the many problems inherent in determining the ages of stars through comparison with stellar evolutionary models. LÄS MER

5. 4. 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

7. 5. Star clusters as engines of galaxy evolution

   Författare :Mattia Sirressi; Angela Adamo; Matthew Hayes; Paul Crowther; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Extragalactic astronomy; Galaxies; Star formation; Interstellar medium; Stellar feedback; Ultraviolet surveys; Hubble Space Telescope; Spectroscopy; Data analysis; Astronomy; astronomi;

   Sammanfattning : Feedback in star forming galaxies is the key process that regulates how many stars form given the available gas reservoir. The radiation, energy and momentum released by the stellar activity and the active galactic nuclei change the physical properties of the gas in the galaxy such as the ionisation state, the density and the kinematics. LÄS MER