The galactic population of ultra-compact white dwarf binaries

Astronomy Unit Seminars
Dr Danny Steeghs (U. Warwick)
David Tsiklauri
November 21st, 2014 at 14:30
GO Jones Room 610

Accreting white dwarfs offer important benchmark populations of close
binary stars that can test and anchor key aspects of binary evolution.
White dwarfs accreting from hydrogen-poor companions are a subclass that
lead to very compact binaries with orbital periods as short as a few
minutes. Such systems, including double white dwarf systems, have likely
undergone two phases of common-envelope evolution, and offer a possible
pathway towards Type Ia explosions. They are also key gravitational wave
sources in the low-frequency range and become luminous objects across the
electro-magnetic spectrum during their accretion phase. I will present our
recent efforts in trying to discover more of such systems using both colour-driven
and variability driven searches. Detailed high-speed observations of individual
systems allow us to determine accurate parameters and study the dynamics
of the accretion flows.