Photometry, spectroscopy and radial velocities of the near contact binary V0775 Cen and the contact binary TW Cru

Presenter(s): David J. W. Moriarty

Affiliation(s): AAQ, VSS, UQ

Session details: Saturday, 2018-03-31 03:00:00, MCON

Abstract

Photometric and spectroscopic analyses of V0775 Cen, a near contact binary with a period of 16 hours and TW Cru, a contact binary with a period of 9 h, indicate both are triple systems. The V0775 Cen spectra are consistent with catalogue values of F0 IV for the primary component; its mass is 1.6 solar and radius 1.7 solar. The effective temperature of the secondary star indicates it has a spectral type of about K4, and its mass is 0.5 solar, yet with a radius of 1.1 solar, it has evolved well past terminal age main sequence. Episodes of emission in the H Balmer and metal lines of TW Cru confirm the conclusion from previously published photometric studies that it is chromospherically active.

Biography

Astronomy: Amateur astronomer since 1956; member Astronomical Society of South Australia 1957 – 1969. Member of Astronomical Association of Qld since 1982. Currently, Emeritus Professor, Honorary Senior Fellow with the Astrophysics group at The University of Queensland (UQ). 1966 – 1969 Ph.D. thesis studies on oxidation of inorganic sulphur compounds by thiobacilli. 1969-1973: Biochemist-Microbiologist quantifying carbon and nitrogen cycles in Lake George, Uganda, with the Royal Society African Freshwater Biological Team, and at Nottingham University, UK. 1973-1975: Queen's Fellow in Marine Science at UQ. 1975 – 1993: Researcher with the CSIRO Marine Divisions. 1992: Guest Professor in Marine Microbiology, Gothenberg University, Sweden. 1997-2013 Honorary Professor, Centre for Marine Studies, UQ. Qualifications: B.Ag. Sc. (Hons.); Ph.D., D.Sc. FASM