Sökning: "stars: low mass - stars: abundances"

Visar resultat 1 - 5 av 13 avhandlingar innehållade orden stars: low mass - stars: abundances.

  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. Charting Circumstellar Chemistry of Carbon-rich AGB Stars

    Författare :Ramlal Unnikrishnan Nair; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; submillimeter: stars; astrochemistry; stars: mass-loss; circumstellar matter; stars: winds; outflows; Stars: AGB and post-AGB;

    Sammanfattning : Stars of low to intermediate initial masses (0.8 - 8 M⊙) enter the asymptotic giant branch (AGB) phase during their late evolution. LÄS MER

  4. 3. Studies of the S-type AGB star W Aquilae : The circumstellar envelope and the fain companion

    Författare :Taissa Danilovich; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stars: binaries: spectroscopic; circumstellar matter; stars: binaries: visual; stars: evolution; stars: mass-loss; stars: AGB and post-AGB; stars: individual: W Aql;

    Sammanfattning : Low- and intermediate-mass stars will all eventually enter the asymptotic giant branch (AGB) phase. AGB stars experience intense mass-loss, generating a significant fraction of the dust and molecular matter that enrichesthe ISM. AGB stars are also responsible for a the production of about half of all elements heavier than iron. LÄS MER

  5. 4. On the Winds of Carbon Stars and the Origin of Carbon : A Theoretical Study

    Författare :Lars Mattsson; Susanne Höfner; Nils Bergvall; Kjell Olofsson; Martin Groenewegen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; AGB stars; carbon stars; mass loss; stellar winds; circumstellar matter; cosmic dust; stellar evolution; nucleosynthesis; galactic chemical evolution; Astronomy and astrophysics; Astronomi och astrofysik; Astronomy; Astronomi; Fysik; Physics;

    Sammanfattning : Carbon is the basis for life, as we know it, but its origin is still largely unclear. Carbon-rich Asymptotic Giant Branch (AGB) stars (carbon stars) play an important rôle in the cosmic matter cycle and may contribute most of the carbon in the Galaxy. LÄS MER

  7. 5. The nature of stars with a common origin: clues from metallicity, elemental abundances, and kinematics

    Författare :Cheng Liu; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Stars: abundances; Galaxy: evolution; Galaxy: solar neighbourhood; Galaxy: bulge; Galaxy: globular clusters;

    Sammanfattning : Most of field stars originate from dissolved star clusters. If the gas cloud is well mixed the stars in the cluster are expected to be chemically homogenous. LÄS MER