Sökning: "circumstellar abundances"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden circumstellar abundances.

  1. 1. Molecules and Dust around AGB stars : Mass-loss rates and molecular abundances

    Författare :Sofia Ramstedt; Hans Olofsson; Fredrik Schöier; José Cernicharo; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; AGB stars; mass-loss; circumstellar abundances; Formation and development of stars; Stjärnors bildning och utveckling; Astronomy; astronomi;

    Sammanfattning : All stars with a stellar mass of about 0.8–8 MSun will end their lives as asymptotic giant branch (AGB) stars. Through their extensive mass loss the AGB stars constitutes an important source of nuclear processed material. LÄS MER

  3. 2. Modelling of molecular clouds

    Författare :Per Bergman; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; molecular radio lines; circumstellar matter; interstellar medium; circumstellar radio lines; H 11 regions; abundances; interstellar matter; galaxies; interstellar radio lines;

    Sammanfattning : .... LÄS MER

  4. 3. Asymptotic Giant Branch stars viewed up-close and far-off : The physics, chemistry, and evolution of their circumstellar envelopes

    Författare :Matthias Maercker; Hans Olofsson; Fredrik L. Schöier; Laurentius B. F. M. Waters; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; AGB stars; evolution; mass-loss; abundances; Astronomy; Astronomi; Astronomy; astronomi;

    Sammanfattning : The asymptotic giant branch (AGB) is the last stage of stellar evolution for stars with masses between 0.8-8 M(sun). This phase is characterised by an intense mass loss, which builds up a circumstellar envelope of dust and gas(CSE). It is through this process that the AGB stars contribute to the chemical evolution of galaxies. LÄS MER

  5. 4. 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

  7. 5. 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