August 11-15, 2014


Testing common envelope on double white dwarf binaries

Jose Luis Avendano Nandez (University of Alberta)

Prof. Natalia Ivanova, University of Alberta; Prof. James C. Lombardi Jr., Allegheny College;

The formation of a compact binary system composed of two white dwarfs (WDs) is believed to include a common envelope event, at least during the last episode of mass exchange between the first-formed WD and a low-mass giant. Low-mass giants have a well-defined relationship between their core masses and radii. This makes the state of the progenitor binary systems at the on-set of the common envelope event in double WD systems to be one of the best theoretically understood, among all known types of post-common envelope systems. In this contribution, we present numerical studies of a common envelope event that involves a binary initially consisting of a 0.36 Msun WD and low-mass giants of different total masses, between 1 and 2 Msun, but with the same core mass, 0.31 Msun. We compare our numerical studies to WD 1101+364 - a double WD system that has well-measured companion masses of 0.31 and 0.36 Msun, and an orbital period of 0.144 days. We discuss possible constraints on energy and angular momentum budgets in a common envelope event, from how the energy and angular momentum are distributed between various parts of the ejected envelope and the binary.

Mode of presentation: oral