Chronology of the Galactic disk with Asteroseismology
Amalie Stokholm (SAC, Aarhus University)
The Milky Way galaxy has been shaped by different processes throughout
its life, affecting its shining elements: the stars. Stars carry
signatures of the conditions in their birth environment and of their
subsequent history, meaning we can use the stars as
fossil records to reconstruct the evolution of the Milky Way. We can
also use the constraints on in-situ formation of external galaxies,
where individual stars cannot be resolved and this kind of study is
impossible.
One challenge is to achieve the necessary accuracy in stellar
parameters for a representative number of stars. Determining physical
properties of stars such as mass, radius, and especially age is
remarkably difficult using traditional techniques. In the
last few decades, the study of stellar pulsations or asteroseismology
has led to a dramatic development in the precise measure of stellar
parameters.
Stellar pulsations are directly related to the internal properties
of stars and thus to the nuclear processes in the stellar interior,
based on which relatively precise stellar ages can be determined.
I have compiled the largest ensemble of red giant stars to date with
measured elemental abundances, astrometric quantities, and precise ages
from asteroseismology. The aim of my project is to build a chronology of
the Milky Way galaxy and study the age aspect
of the chemical and kinematic features of the Galactic disk. Using a
data-driven clustering algorithm, I am looking at the similarities and
differences between stars born at different epochs, studying the
signatures of events in the Milky Way’s past.