Zoo Station

The last time my friend Shami Chaterjee was in New York, we discussed briefly his work on pulsars at the Harvard-Smithsonian Center for Astrophysics, since I have an amateur interest in astronomy. At the time, Shami told me his team was on the verge of a big breakthrough and that the announcement would probably occur in the next few months. Over to New Scientist, where the discovery (by Shami's team) of the fastest pulsar to escape the Milky Way has just been announced.

Astronomers have spotted the fastest moving stellar corpse to date - and it appears to be headed straight out of our galaxy. A team from the US National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, and the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts, US, clocked the dead star at 1100 kilometres per second. The object, called B1508+55, is a rotating neutron star, or pulsar. It is the superdense core of a massive star that exploded as a supernova about 2.5 million years ago. The explosion seems to have ejected the pulsar with such force that it will eventually escape the Milky Way entirely, says team member Shami Chatterjee, an astronomer with NRAO and CfA.

However, current simulations of supernovae have never produced such breakneck speeds. In the models, the newly formed neutron star starts out fast but soon slows down when material from the outer layers of the exploded star crashes back onto it. In 2004, the first 3D model of a supernova found that the blast could send a neutron star flying at about 200 kilometres per second - nearly six times slower than the new record holder. The researchers watched this pulsar for two years with the Very Long Baseline Array - a collection of 10 radio-telescopes scattered from Hawaii to the US Virgin Islands. They determined the pulsar lies 7700 light years away and gauged its speed by observing how its position on the sky changed in that time. From this, they traced its route backwards to its likely birthplace 2.5 million years ago in a region full of huge stars in the constellation Cygnus. The stars are so massive that they will eventually blow up as supernovae, potentially spawning other speedy stellar corpses.

The full press release is here. If you're interested in reading more about these fascinating inter-stellar corpses, head over to the Goddard Flight Center or you could head here, if you'd like to listen to the pulsing of these neutron stars. In particular, listen to The Vela Pulsar.