David Moriarty

David’s career has been in the field of aquatic microbial ecology. He was awarded a D.Sc. by the University of Adelaide and was made a Fellow of the Australian Society for Microbiology in 1991. He was an Honorary Professor in the UQ Centre for Marine Science for 15 years.

Astronomy has been a life-long interest. He has established an observatory near Stanthorpe — a dark sky site at 750 m altitude southwest of Brisbane. Since 2011, he has been collaborating on research projects with members of the Variable Stars section of the Royal Astronomical Society of NZ. His research field now is photometry, spectroscopy, and astrophysical modelling of eclipsing binary stars. He has been an Honorary Senior Fellow in the UQ School of Mathematics and Physics with the Astrophysics group since 2014. He has been operating the ANU 2.3m telescope, the second largest at Australia’s national Siding Spring Observatory for past 6 years (2016-2021). He is an Honorary Member of the Astronomical Association of Queensland. He has published refereed papers in astronomical and astrophysical journals.

Title: Spectroscopic and photometric analyses of several eclipsing binary systems with pulsating components and complexities of determining radial velocities in systems with three components

The cross-correlation function (CCF) is the main tool used by astronomers to determine radial velocities of stars, but it does not work well for close and contact binary systems. In fact, the radial velocities of secondary stars that are several magnitudes fainter than the primary stars cannot be determined with the CCF. I have found that Slavec Rucinski’s broadening function can be used and will describe how I am applying that to close binary systems with Bogumil Pilecki's RAVESPAN programme. Triple systems are more difficult to analyse, but the radial velocities of the binary components can be determined by comparing their velocities with values of the Na I D and Balmer lines, especially at quadrature phases.