Tuesday 21 Mar 2023: [Journal Club] - On the frequencies of circumbinary discs in protostellar systems
Dan ELsender - University of Exeter
4th Floor interaction area 11:15-11:45
The formation and evolution of protostellar discs is key to the understanding of both star and planet formation. Interferometers such as the Atacama Large (sub)-Millimetre Array (ALMA) and the Very Large Array (VLA) have allowed us to observe deep into star-forming regions to observe discs of embedded Class 0 and I protostars (e.g. Tychoniec et al. 2018). Recent efforts have made detections of circumbinary planets (e.g. Doyle et al. 2011), they have an occurrence rate similar or higher than that of single stars (Armstrong et al. 2014). With the growing catalogue of observed discs (e.g. Tobin et al. 2020) and circumbinary planets it is a good time to compare observed discs to those produced in hydro- dynamical simulations (e.g. Bate 2018), and how the environment impacts the properties of discs (e.g. Elsender & Bate 2021; Qiao et al. 2022).
We present the detailed analysis of circumbinary discs formed in the solar metallicity calculation of Bate (2019). We find, the fraction of pure binaries that host a circumbinary disc has a bi-modal distribution, which peaks at around 1 au and 30 au. Binaries in hierarchical systems show a weaker bi-modality. Close to 90% of very close pure binaries host a circumbinary disc. Circumbinary discs formed in the calculation had an average mutual inclination of 33.6 degrees, consistent with the literature value of observed circumbinary discs of 37.4 degrees. This may have a significant impact on the occurrence rate of circumbinary planets.