Special Astrophysics Seminar

On Spiders and Binary Pulsars

René Breton

University of Manchester

In recent years, the fastest growing class of binary pulsars has been that containing an energetic millisecond pulsar strongly irradiating a low-mass companion in a compact orbit. Dubbed “spiders” because of the cannibalistic behaviour of the host pulsar, they in fact subdivide into two sub-classes: “black widows” and “redbacks”, which appear to differ only by the mass of the companion. Among other things these binaries prove to be good for measuring pulsar masses. The few measurements obtained so far indicate that they likely constitute a rather massive sub-population of neutron stars. Recently, members of the redback subclass have also been witnessed to experience state transitions between pulsar and low-mass X-ray binary states. In this talk, I will discuss some recent mass measurements as well as notable behaviours, such as “spotty” companion surfaces, secular flux changes and state transitions.