RSAA Colloquia / Seminars / Feast-of-Facts: Tuesday, 13 November 2018, 11:00-12:00; Duffield Lecture Theatre

Rajika Kuruwita

"The formation and evolution of discs around young binary stars"

I investigate factors that influence the lifetime of protoplanetary discs in binary stars with the broad understanding that the longer the lifetime of a disc (in a single or binary star) the higher the likelihood of producing planets. I present theoretical work done using the AMR MHD code FLASH on the formation of binary stars and the evolution of their discs in these systems. I simulated the collapse of molecular cores until the formation of protostars and followed the early evolution of these systems. I investigated the influence that binarity has on the global evolution of a young stellar system, including looking at mechanisms such as accretion of material, jets and outflows, and dynamical interactions. I also present observational work done to determine the typical survivability of discs in binary star systems. This work was carried by using the Australian National University 2.3m telescope to search for radial velocity variation in disc-bearing members of the $11$ and $17$~Myr regions Upper Scorpius and Upper Centaurus-Lupus. I find the binary fraction of disc-bearing stars in these regions do not differ significantly from the field star binary fraction. This may suggest the typical lifetime of discs in single and binary stars is comparable. Overall I find that while in some scenarios binary stars may produce hostile environments for planet formation via the destruction of circumstellar discs, the formation of large circumbinary discs is possible. This can lead to the formation of planets about binary stars to be just as likely as the their formation around single stars.