Dead Star Set to Escape the Milky Way

slackah wrote to mention a NewScientist.com article discussing a fast-moving stellar corpse on its way out of our galaxy. From the article: "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."

Comments

In other news...

[elgatozorbas]

Dard Vader not amused

Re:Tracking

[1u3hr]

I wonder how long we can track this object once it leaves the galaxy. Any perturbations of its path will tell us about the dark matter

Fast, for a star, but it's 1/300th of c. So it'll be at least 300,000 years to get 1000 ly out, getting to the edge of the galaxy. By then we'll either be extinct or know all about the dark matter.

Re:How is this possible?

[imsabbel]

The main point is: the core isnt EXPLODING, its COLLAPSING to a neutron star. The "explosion" is just a rebounce off the core (_slightly_ simplified :) ).

After the collapse, the kinetic energy of the quasi free falling neutron matter will overcompress the neutron star core, and then it will oscillate.

As the collapse istn something perfectly symetrical, there will be significant amplitude of the first harmonic of the oscillation. Thus (for example) the matter hitting the star on one hemisphere will have the core expanding in their direction with quite some speed, while the other side will see it receeding). As the impact isnt very long, there wont be time to average out. In the moment the hull impacts, the core will "push" itself away from that quasi-spherical shell thats hitting it.

(you have to remember: there is significant mass in that shell. Only a small part of the star actually ends of in the neutron star, so there IS enough mass in the hull for conservation of momentum)