Pulsars are rapidly rotating neutron stars—the dense remnants of stars much more massive than the Sun. Some pulsars are in binary systems, and when they feed off their companion star, their rotation rate can increase until they’re spinning hundreds of times per second. Known as millisecond pulsars, these are often also strong emitters of gamma rays, but no one had identified one through gamma ray observation alone…until now.
Astronomers have now used the Fermi Gamma-Ray Space Telescope to identify a “black widow” pulsar that’s stripping mass off a close companion star while simultaneously evaporating it by emitting intense radiation. It’s having these dramatic effects because the pulsar and its companion orbit each other so closely that they complete an orbit once every 93 minutes, making this the tightest black widow binary yet discovered. [Read more....]