Speaker: David Buckley (South African Astronomical Observatory, Cape Town, South Africa)
Title: “Discovery of a White Dwarf Pulsar”
I discuss the recent discovery of a spinning white dwarf in the binary system AR Scorpii which shows all of the usual hallmarks of a pulsar. Photometric observations established that it pulses at the 2 minute spin and beat periods, from the UV to radio wavelengths, and its luminosity is dominated by synchrotron emission, powered by the spin-down of the strongly magnetic white dwarf. Polarimetry observations have strengthened the arguments that the white dwarf in AR Sco is analogous to a pulsar, with the optical polarization showing similar characteristic to that seen in the Crab pulsar. The pulsation and spectral energy distribution properties are explained by strong MHD interactions between the magnetic white dwarf magnetic and the M-dwarf companion.