Dr Andrew Willes (University of Sydney)

Electron-cyclotron maser emission from white dwarf pairs and white dwarf planetary systems - Dr Andrew Willes Colloquium

ATNF Marsfield Lecture Theatre

Abstract

Binaries consisting of a magnetic white dwarf in near synchronous rotation
with
the close orbit of a non-magnetic white dwarf can generate
electrically-powered
X-ray emissions, where induced currents driven within the binary produce
resistive heating in the white dwarf atmosphere. This is analogous to jovian
auroral
emissions generated by the electrical interaction between Jupiter and its
moons
Io, Europa, Ganymede and Callisto. This model successfully accounts for the
puzzling characteristics of the observed X-ray luminosity from the 9.5-min
binary
RX J1914+24, and is consistent with high-precision timing measurements of the
X-ray pulses. In this talk, I will explore the possibility that white dwarf
pairs
produce radio emissions with a distinctive signature, by analogy to jovian
radio
emissions controlled by Jupiter's moons.

This model is also applicable to Earth-like planets in close orbits around a
magnetic white dwarf. These are remnant systems, where an Earth-like planet
survives the expansion phases of the post-main-sequence star and remains in
orbit around the emergent white dwarf. I will discuss formation scenarios of
white dwarf planetary systems and present a simple model to predict radio flux
densities from white dwarf pairs and white dwarf planetary systems. In this
talk,
particular emphasis is placed on the detectability criteria for white-dwarf
systems using the ATCA and LOFAR.