1. Galactic chemodynamical evolution
  2. Galactic Archeology and ancient substructures
  3. Extra mixing processes in evolved stars
  4. RS CVn type stars
  5. Open cluster studies

 

Galactic chemodynamical evolution

The formation and evolution of galaxies is one of the great unsolved problems of modern astrophysics. The only galaxy available for detail studies is our Milky Way Galaxy, but our Galaxy is complex structure and evidently undergone very complicated formation history.

 Low mass stars have long lifetimes, comparable to the age of the Galaxy and their atmospheres have preserved much of their original chemical composition. These stars are ‘fossils’ containing information about chemical composition of galactic material at the moment of birth of these stars. Therefore low to intermediate mass stars of different ages preserved information about a history of evolution of the Galaxy in their chemical composition.

(Papers)

Galactic Archeology and ancient substructures

Our Milky Way Galaxy is complex structure and evidently undergone very complicated formation history. Galactic Archeology attempts to reveal that history by reconstructing the lost stellar substructures of the Galaxy, thereby backtracking formation processes. ‘Signposts’ of historic evolutionary events are chemically and dynamically linked stellar substructures. Those ‘fossil’ substructures are identified and backtracked to former evolutionary events by combining together stellar chemical analysis data and dynamical analysis. Stars formed together have same chemical composition, thereby if star-forming aggregates have unique ‘chemical signatures’, we can use chemical composition to ‘tag’ disk stars to a common formation event.

 

 

Extra mixing processes

Stellar evolution is caused by nuclear reactions in stellar cores slowly changing the internal stellar composition and structure. Mixing processes in stellar interiors can change properties of stellar material and structure, and can influence evolution of the star. As stellar evolution models are widely used in the modern stellar astrophysics, mixing processes potentially could have a wide impact on various seemingly unrelated astrophysical problems.

Investigation into abundances of mixing-sensitive elements can independently verify stellar evolution models. Numerous modern observations provide compelling evidence of additional or ‘extra’ mixing process in the low–mass red giant (RGB) stars unpredicted by standard evolution model, i.e. evidence that the standard stellar evolution model is incomplete

(papers)

 

RS CVn type stars

 Open clusters

Open clusters are important tools for the study of the Galactic disk as well as for understanding of stellar evolution. Since cluster members initially were of identical chemical composition, all changes in stellar atmospheres are related to internal and external processes of stellar evolution.