Asteroseismology involves using the oscillation frequencies of a star to measure its internal properties.

A star is a gaseous sphere and will oscillate in many different modes when suitably excited. The frequencies of these oscillations depend on the sound speed inside the star, which in turn depends on density, temperature, gas motion and other properties of the stellar interior.

This analysis, called asteroseismology, yields information such as composition, age, mixing and internal rotation that cannot be obtained in any other way and is completely analogous to the seismological study of the interior of the Earth.

The SIfA asteroseismology group play a central role in the interpretation of oscillation data for different types of pulsating stars in different evolutionary stages, such as the rapidly oscillating Ap stars, δ Scuti stars, and the solar-like oscillators.

 

 

Individual waves travelling through a hypothetical star. Some waves propagate only around top layer of a star, while others travel right through the center. The waves cause the star to vibrate and brighten. Credit: NASA/JPL-Caltech
Academic staff

Tim Bedding is a professor of astrophysics whose research focuses on asteroseismology. He is interested in studying oscillations in many different types of stars, from Sun-like stars to red giants, using observations from NASA’s Kepler and TESS missions.

Simon Murphy works on pulsating stars, binary stars, and especially pulsating stars in binary or multiple systems.

Tim White uses the most sensitive observational tools of modern stellar astrophysics to determine the properties of stars with the utmost precision. Additionally, Tim uses long-baseline optical interferometry to directly measure the sizes and effective temperatures of stars.

Students

Isabel Colman has recently completed her PhD. Her major PhD project involved writing an image subtraction photometry pipeline for use on Kepler images. She is interested in the photometry of variable stars in crowded fields, and methods of signal blending analysis and false positive identification.

Jason Drury is a final year PhD student studying the nominal Kepler open clusters through Kepler’s large “superstamp” images and Gaia data. His research has focussed on photometric, astrometric, and asteroseismic ensemble analysis of these clusters including membership determinations.

Daniel Hey is a current PhD student working on the delta Scuti variables and binary stars. He is particularly interested in pulsation timing and statistical inference.

Connor Jarvis is an honours student studying Delta Scuti stars, seeking to further understanding and perform mode identification on these stars. Connor has previously undertaken data analysis projects using Python studying the Kepler K2 light curve pipelines

Yaguang Li studies oscillations in Sun-like stars and red giant stars. He develops tools to understand the internal structures of those stars, by comparing space data from Kepler and TESS mission with theoretical models. His interests include large-scale data processing, stellar modelling, tests of asteroseismic scaling relations, and constraints of angular momentum transport.

Li Gang focuses on Kepler gamma Doradus stars. These stars pulsate in gravity and Rossby modes, which carry information of steller interiors. He measures their near-core rotation rates and some other inner physics processes, such as angular momentum transport.