Asteroseismology

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.

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.

Courtney Crawford studies pulsations of red giants using both models and observations. She also works with hydrogen-deficient giants, especially those formed from double white dwarf mergers such as the R Coronae Borealis variables. 

Daniel Huber studies the fundamental properties of exoplanets and the stars that host them, by combining observations from ground-based telescopes and NASA missions. He also conducts research on the structure and evolution of stars and stellar populations in our galaxy.

Prasad Mani specializes in applying deep-learning techniques to analyze δ-Scuti pulsations data obtained from NASA/TESS. Additionally, he focuses on feature engineering to construct realistic datasets for training machine learning models.

Nikita Nikultsev is an honours student modelling the evolution of hydrogen-deficient, carbon-rich supergiants from initial mergers of white dwarfs. His investigations include whether similar processes could result in the production of cooler cousins. His interests include simulations, data analysis, computation and optimisation.

Filip Chatys studies long Period Variables with TESS and Kepler space mission data using asteroseismic analyses.

Simon Murphy uses stellar pulsations to characterise stellar masses, ages and metallicities. His research focusses on pulsating A/F stars, particularly delta Scuti stars, and stellar chemical peculiarities such as the λ Bootis phenomenon. He also uses pulsation timing to find and parametrise binary systems.

Tim White formerly used asteroseismology and interferometry to determine the properties of stars with the utmost precision. He now works at the University of Sydney as a research software engineer on a wide variety of projects ranging from agriculture to medicine.

Daniel Hey is a former PhD student at the University of Sydney. He is now a variable stars postdoctoral fellow at the University of Hawaii, working on asteroseismology of delta Scuti and M-giant variables.

Jason Drury is a former PhD student studying Kepler open clusters through “superstamp” images and Gaia data. His research has focussed on photometric, astrometric, and asteroseismic ensemble analysis of these clusters. He now works as a data scientist.

Connor Jarvis is a former honours student studying Delta Scuti stars, seeking to further understanding and performing mode identification on these stars.

Doug Compton is a former PhD student. He uses a wide range of asteroseismic data analysis techniques to understand the physical properties of various classes of oscillating stars. He now works as a data scientist.