The NSAS General Meeting for March will be on Tuesday the 20th March at 7:30 PM at Regis Hall, Regis Campus, St Ignatius College, Lane Cove.

Our guest speaker is Prof Orsola de Marco from Macquarie Uni Astrophysics. Abstract follows.

As usual, guests are most welcome!

David Wallace

The common envelope binary interaction, a “grand challenge” problem.

When a star grows to giant size it can engulf a nearby companion orbiting it. This interaction leads to the shrinking of the orbital separation and the creation of either a compact binary or a merged star. Since the 70s we have hypothesised these interactions to give rise to compact binaries such as cataclysmic variables of X-ray binaries and to binaries that later on merge, giving rise to supernovae Ia and gravitational wave emission. Today, thanks to the advent of time-resolved astronomy on large scales, we have observed several common envelope interactions (which are fast, happening on day-month timescales) and we are therefore in a position to test our models. Here I will present the latest modelling efforts, the challenges and the benefits. I will also present a special class of common envelope interactions, happening between a star and its planetary system.