Sökning: "Stars: mass-loss"

Visar resultat 11 - 15 av 25 avhandlingar innehållade orden Stars: mass-loss.

1. 11. Companion wind shaping in binaries involving an AGB star

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

   Sammanfattning : 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. LÄS MER

3. 12. Molecules at stellar death: from the winds of massive evolved stars to supernova remnants

   Författare :Sofia Wallström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stellar mass-loss; supernova remnants; circumstellar matter; IRAS 17163-3907; yellow hypergiant stars; Cassiopeia A;

   Sammanfattning : Massive stars play a key role in the chemical and dust budget of the galaxy, producing heavy elements, molecules, and dust. At the end of their lives they evolve through stages of significant mass-loss which affect the subsequent evolution of the star, including whether or not it will eventually explode as a supernova (SN). LÄS MER

4. 13. Theoretical Studies of Binaries in Astrophysics

   Författare :Johann Dischler; Astronomi - Genomgår omorganisation; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomi; Astronomy; Galaxy: centre; Stars: mass-loss; Binaries: close; Binaries: eclipsing;

   Sammanfattning : This thesis introduces and summarizes four papers dealing with computer simulations of astrophysical processes involving binaries. The first part gives the rational and theoretical background to these papers. In paper I and II a statistical approach to studying eclipsing binaries is described. LÄS MER

5. 14. The death throes of massive stars

   Författare :Sofia Wallström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; submillimeter: ISM -- ISM: supernova remnants -- ISM: individual objects: Cassiopeia A -- circumstellar matter -- stars: AGB and post-AGB -- stars: mass-loss -- stars: individual: IRAS 17163-3907 -- quasars: absorption lines -- quasars: individual: B 0218 357 -- galaxies: ISM -- galaxies: abundances -- ISM: molecules;

   Sammanfattning : Massive evolved stars affect their local surroundings as they go through phases of intense mass-loss and eventually explode as supernovae, adding kinetic energy and freshly synthesised material to the interstellar medium. The circumstellar material ejected by the star affects the shape and evolution of the future supernova remnant, and how the material is incorporated into the interstellar medium. LÄS MER

7. 15. Probing the effect of UV radiation on the chemistry in circumstellar envelopes around evolved stars

   Författare :Maryam Saberi; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Stars: abundances - Stars: AGB – Stars: individual: R Scl – Stars: binaries – Stars: carbon – Stars: circumstellar matter – Stars: chromospheres – Ultraviolet: stars;

   Sammanfattning : Low to intermediate mass (0.8 - 8 M⊙) stars lose a substantial amount of their mass in the last phase of stellar evolution, the asymptotic giant branch (AGB) phase. Hence, they are one of the main suppliers of dust and gas in the interstellar medium and important for the enrichment of galaxies. LÄS MER