Search for dissertations about: "teoretisk astrofysik"

Showing result 1 - 5 of 95 swedish dissertations containing the words teoretisk astrofysik.

  2. 1. Mass Loss of Evolved Stars : Improving Mass-Loss Rates and Distances

    Author : Miora Andriantsaralaza; Paul Barklem; Elvire De Beck; Susanne Höfner; Jacco van Loon; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; AGB stars; Mass loss; Distance; Circumstellar matter; Radio interferometry; Stellar evolution; Fysik med inriktning mot astrofysik; Physics with specialization in Astrophysics;

    Abstract : In the final stages of their lives, low to intermediate-mass stars enter the Asymptotic Giant Branch (AGB) phase, where they experience significant mass loss through dusty stellar winds. This mass loss is pivotal, not only for the chemical enrichment of the interstellar medium, setting the stage for new stars and planets to form, but also in dictating the evolution and the ultimate fate of the stars themselves. READ MORE

  4. 2. Atomic Processes in Stellar Atmospheres : Inelastic Collisions and Effects on Late-type Spectra

    Author : Yeisson Fabian Martinez Osorio; Paul Barklem; Karin Lind; Nikolai Piskunov; Carlos Allende Prieto; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Spectral line: formation; atomic data; stellar abundances.; Fysik med inriktning mot astrofysik; Physics with specialization in Astrophysics;

    Abstract : Chemical abundances as measured from stellar spectral lines are often subject to uncertainties due to lack of accurate data for inelastic collisions, which is needed for non-local thermodynamic equilibrium (non-LTE) modelling. For cool stars, understanding of collision processes with electrons and hydrogen atoms is required to achieve high precision measurements. READ MORE

  5. 3. Companion wind shaping in binaries involving an AGB star

    Author : Lam Doan; Sofia Ramstedt; Eric Lagadec; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; AGB and post-AGB stars; mass-loss; radio lines; binaries; wind shaping; Astronomy; Astronomi;

    Abstract : Stars of initial masses between 0.8-8 M☉ will become "asymptotic giant branch" (AGB) stars during the final stages of their evolution. During this phase, the stars are characterized by low velocity and high-density winds. READ MORE

  6. 4. Statistical Methods in Quantitative Spectroscopy of Solar-Type Stars

    Author : Alvin Gavel; Andreas Korn; Ulrike Heiter; Coryn Bailer-Jones; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Astronomi;

    Abstract : Galactic archaeology is the research field that attempts to reconstruct the history of the Milky Way, using primarily the tools of astrometric studies and chemical studies. The latter in turn uses stellar spectroscopy. READ MORE

  7. 5. The circumstellar envelope of the S-type AGB star π1 Gruis

    Author : Doan Duc Lam; Kay Justtanont; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; AGB and post-AGB stars: mass-loss binaries: general - radio lines: stars - stars: general stars: individual: π1 Gru.; Astronomy; Astronomi;

    Abstract : .... READ MORE