Asteroseismic modelling of intermediate-mass stars
Two of the most impactful open questions in stellar structure and evolution theory concern the mechanism(s) driving
the transport of chemical elements and angular momentum. The physical mechanisms at play and the corresponding efficiencies
are not fully understood at present. A better understanding of these mechanisms is of great importance to many fields of astrophysics,
such as studies of chemical enrichment, evolved stars and stellar remnants, galactic archeology, and exoplanets, as these all rely
on accurate predictions of stellar evolution.
Asteroseismology, the study of stellar pulsations, has proven to be a powerful tool in constraining stellar interiors to high precision.
The so-called gravity (g) modes are oscillations restored by the buoyancy force and are most sensitive to properties of the deep stellar interior.
These stellar pulsations are described by spherical harmonics. The animations below illustrate what these spherical harmonics look like (in real stars the amplitudes are much smaller).
My PhD research focusses on studying a unique sample of pulsating F-type g-mode variables, known as gamma Doradus stars. The main purpose of my PhD is to
provide empirical constraints to investigate the relations between the efficiency of chemical mixing and angular momentum transport as a function of
stellar mass, age, and rotation. I am taking a forward modelling approach, confronting long time-base photometry from the NASA Kepler space telescope
with stellar structure and evolution models, and stellar pulsation models.
The animation below that I have made for the ESA PR event of Gaia DR3 shows the different dipole and quadrupole modes in a rotating star.
The three stars at the end are real pulsating F-type stars, where I show the three most dominant modes for each star. The sound represents the relative
pulsation frequencies, shifted to the audible frequencies for the human ear.