Strongly magnetized stars that shoot beams of radiation from their poles, called pulsars, have previously always been identified as dense neutron stars. But researchers now report the discovery of a pulsar that is a white dwarf — the spent remnant of a star like the Sun.
In 2016, astronomers reported that AR Scorpii is not a single star, as they had thought, but comprises two stars orbiting each other: a red dwarf and a larger white dwarf. David Buckley of the South African Astronomical Observatory in Cape Town and his collaborators have since measured the polarization of the light from the system and showed that it is produced by focused beams similar to those of pulsars. It is not clear why such systems seem to be so rare, Buckley says.