Ensemble asteroseismology and hierarchical bayesian models: new inferences of astrophysics with oscillating stars

Hall, Oliver J. ORCID: 0000-0002-0468-4775 (2020). Ensemble asteroseismology and hierarchical bayesian models: new inferences of astrophysics with oscillating stars. University of Birmingham. Ph.D.

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Abstract

Asteroseismology – the study of stellar oscillations – is one of the key tools used to study stars in modern astronomy. This thesis focuses on asteroseismology of solar-like oscillators, which exhibit variability driven by the same mechanism as the Sun. By studying variations in the brightness of stars on their surface, asteroseismology probes the full stellar interior, giving insight into stars’ internal processes and fundamental properties.
In this thesis, I provide an introduction to asteroseismology and the state of the field. This is followed by a description of asteroseismic analysis tools I developed for the open source Python package ‘Lightkurve’, and a presentation of two studies that use asteroseismology to probe different aspects of astrophysics.
The first study uses an asteroseismic ensemble of 5576 evolved Red Clump stars to calibrate data from the Gaia mission, and quantify systematic differences in asteroseismic modelling techniques. The second focuses on 91 main sequence stars like the Sun, using asteroseismology to measure their rotation rates. Along with asteroseismic ages, these new rotation rates are used to quantitatively state that stars experience a change in how they lose angular momentum half-way through their main sequence lifetimes. A common thread throughout both these studies is the use of Bayesian statistics, which allows us to leverage large asteroseismic ensembles to make inferences about adjacent fields of astronomy.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):