Thursday, July 5, 2012

Fastest Pulsar In The Galaxy

How fast you ask?

We'll get to that.  A pulsar is a spinning, magnetized neutron star that is detected by its pulsating emissions of radio light and X-rays.  A neutron star is the Manhattan-sized sphere of extremely dense matter left over after a star more than 1.38 solar masses but less than ten solar masses goes supernova.

The sort of supernova that creates a neutron star occurs when a star is massive enough to make the inevitable mistake of attempting to fuse the iron formed at its core as it approaches the end of its life.  Where other stages of stellar evolution can take millions of years this final step lasts only moments.  Fusing iron consumes energy rather than creating it so the energy pressing outward from within the star is suddenly insufficient to resist the gravitational forces attempting to crush the star.  The shell of the star collapses upon the core, is repulsed by quantum degeneracy pressure, and the star disintegrates in a flash of light brighter than its host galaxy.

The pint-size, super-dense core (a tablespoon of the stuff weighs 900 time as much as the Great Pyramid or ten million tons, if you prefer) at the center of this catastrophe conserves the angular momentum of the destroyed star so a neutron star spins on its axis from one to a thousand times a second, while giving off beams of radio waves and x-rays from its magnetic poles.  Depending on where the beam is pointing it can be perceived as a staccato rhythm as the stream of electromagnetic radiation rotates by.

Interestingly, if a supernova occurs in a lop-sided manner, the neutron star can be spit out of the center of the exploding star.  Of course, "spit out" means different things in different neighborhoods.  IGR J1104-6103 is the not so clever name assigned to the neutron star ejected from supernova remnant SNR MSH 11-61A seen in the picture above.  It's zipping away at 6 million miles an hour.  Imagine a cannonball the size of New York City that weighs more than our sun making the trip from the Earth to Mars in about 5 minutes.  Yep, pretty snappy.  In the photo above pulsar IGR J1104-610 is at the narrow end of the green comet-like smudge.  That smudge is a wake of x-rays created by the passage of the neutron star through space.  The wake is three light years long! 

In the mean time, the superheated, massively irradiated shell of the star, bubbling with all the elements needed to create nebula, next generation stars, new planets, and life in the universe, is cast upon the galactic deep in the form of a supernova remnant.  In the fullness of time the universe is seeding itself with all the ingredients it needs to make us.

"We are star stuff.  We are the universe made manifest trying to figure out itself."

Pretty neat.

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