Seminar: Circumbinary discs around post-AGB stars

  • Date: –15:00
  • Location: Ångströmlaboratoriet, Lägerhyddsvägen 1 Hjorter’s room (Å73101)
  • Lecturer: Robert Izzard, University of Surrey, UK
  • Contact person: Sofia Ramstedt
  • Seminarium

Post-AGB stars with discs are all binary systems. Post-AGB binaries are also eccentric, in every sense of the word. Given that many post-AGB objects likely experienced a common envelope, or were close enough that tides should have made them circular, it is difficult to understand why they are now so eccentric. We have been working on modelling post-common envelope, circumbinary discs in the context of binary stellar populations and their properties. I shall present the first – very preliminary! – results of this work relating disc formation, properties and survival, as well as feedback on the orbit of the post-AGB binary at the centre of the discs. Can these discs really make post-AGB binaries eccentric or are they more sinister long-term threats to the survival of the binaries? Can we explain post-AGB star properties through “reaccretion” of disc material? What about the number of post-AGB binaries and whether they are post-AGB or post-GB? And, of course, do these discs survive as debris discs or planets?