2016 schedule

Fri 25th
11:35-12:00
Theatre 106

Photometry and astrophysical modelling of the Eclipsing Binary BC Gruis

David Moriarty

AAQ, VSS, UQ

BC Gruis is an over-contact system with the components differing by about 9% in temperature and thus displaying uneven eclipse depths.  The orbital period has changed since discovery, which may be due to error in the original determination and also possible mass exchange and/or the effects of a third component. A third component in the system, revealed by spectroscopy, has been reported from the ESO and may contribute to variability in the orbital period.  An astrophysical model was developed by Plewa & Kaluzny in 1992 before the 3rd component was discovered. A revised model will be presented.  

David has been an amateur astronomer since about 1955 as a member of ASSA (until 1969). He has been a member of the AAQ for more than 30 years; also a member of VSS and AAVSO. He is currently retired, but is a Professor Emeritus and Honorary Senior Fellow in the UQ School of Maths & Physics (although his field of research has been aquatic microbial ecology and biochemistry!)