For centuries, variable stars have been crucial in the study of stellar populations. Astronomers have conducted rigorous observations over many decades in order to understand the physics behind their varying brightnesses. These unique objects come in many flavours, some changing regularly and predictably, with others changing erratically, sometimes lying dormant for years at a time. The changes that occur in a variable star occur on human timescales, making them one of the few astronomical objects whose evolution we can observe in real time.
However, these variables are not just fascinating probes of stellar evolution; they are also powerful distance indicators, enabling us to measure distances to objects within our Galaxy and beyond. Over the past 100 years, variable stars have made essential contributions to our understanding of the evolution of the Universe, and continue to be at the forefront of modern astrophysics to this day.
In this lecture, I will discuss the vast contributions that variable stars have made to astronomy and cosmology. I will describe how variable stars are used to create three-dimensional maps of nearby galaxies, revealing new details about their structure and evolution. I will discuss the advances in cosmology brought about through variable star studies, such as Hubble’s discovery of the expanding Universe, the discovery that this expansion is accelerating, and what this tells us about the ultimate fate of our Universe.
Background of Lecturer:
Dr Vicky Scowcroft is a Lecturer in Astrophysics at the University of Bath. She moved to Bath in 2016 as a University of Bath 50th Anniversary Prize Fellow. After receiving her PhD in Astrophysics from Liverpool John Moores University in 2010, she moved to The Observatories of the Carnegie Institution for Science in Pasadena, California, working as part of the Carnegie Hubble Program team to make the first measurement of the expansion rate of the Universe using mid-infrared observations. Her research uses variable stars as precision distance indicators in order to determine the structure of nearby galaxies and the evolutionary history of our Universe.