Sökning: "stars : evolution"

Visar resultat 16 - 20 av 104 avhandlingar innehållade orden stars : evolution.

  1. 16. 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. 17. Magnetic fields of cool stars from near-infrared spectropolarimetry

    Författare :Alexis Lavail; Oleg Kochukhov; Nikolai Piskunov; Gaitee Hussain; Jeff Valenti; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stars: magnetic field; stars: pre-main-sequence; stars: late-type; techniques: spectroscopic; techniques: polarimetric; Astronomy; Astronomi;

    Sammanfattning : Magnetic fields rule many physical processes in and around stars throughout their lifetime. All cool stars possess a magnetic field, likely generated by dynamo processes. In order to properly understand the evolution of cool stars, we need to understand their magnetism. LÄS MER

  4. 18. Dynamical atmospheres and winds of M-type AGB stars

    Författare :Sara Bladh; Susanne Höfner; Kjell Eriksson; Patricia Whitelock; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Late-type stars; AGB stars; stellar winds; atmospheres; mass-loss; outflows; circumstellar matter; dust; hydroynamics; radiative transfer; Astronomy with specialization in Astrophysics; Astronomi med intiktning mot astrofysik;

    Sammanfattning : Mass loss, in the form of slow stellar winds, is a decisive factor for the evolution of cool luminous giants, eventually turning them into white dwarfs. These dense outflows are also a key factor in the enrichment of the interstellar medium with newly produced elements from the interior of these stars. LÄS MER

  5. 19. 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

  7. 20. Infrared spectroscopic investigations of stellar winds from red giants

    Författare :Nils Ryde; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; AGB stars; stellar evolution; late-type stars; mass loss; circumstellar matter; stellarwinds; infrared spectroscopy; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Theoretical Astrophysics; teoretisk astrofysik;

    Sammanfattning : .... LÄS MER