Monday, November 7, 2011

Space / Astronomy: New Discovery Challenges Theory on Formation of Millisecond Pulsars

Space / Astronomy
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New Discovery Challenges Theory on Formation of Millisecond Pulsars
Nov 7th 2011, 19:17

I've been on a bit of a gamma-ray kick lately. Sure I'm a little biased, that being my primary area of research and all, but there have also been some very important results to come out of this field in recent weeks and months.

The latest announcement comes to us from data taken with the Fermi LAT instrument, an orbiting gamma-ray satellite launched in 2008. Fermi has been on a roll, discovering more than 100 new pulsars since launch, a milestone that was crested with the recent discovery of nine more sources.

Additionally, a new millisecond pulsar (MSP) has been detected by the observatory that could challenge our very understanding of these objects.

Our current understanding maintains that millisecond pulsars are the result of very old neutron stars that are "spun-up" by the accretion of matter from a companion star. This happens at the end of their lives as the magnetic field weakens causing the matter to build up very quickly, causing a dramatic increase in angular momentum.

Therefore, most millisecond pulsars are estimated to be billions of years old, but this new star only appears to be about 25 million years old.

This result is leading some scientists to question the very mechanism by which these objects are created. But I'm not so sure.

The method used to calculate the age of these objects is using a quantity known as the spin-down power, which is essentially a measure of how much energy the star is loosing per second. It is obtained by measuring the rate at which the pulsar is spinning and the rate at which it is slowing down.

However, there might by external forces influencing these quantities, therefore making the pulsar appear younger than it really is.

At the very least it seems premature to begin calling into question the fundamental principles of neutron star formation.

In either case, NASA has put out some cool media related to this discovery. Check out this animated map that shows the location of the pulsars that have been discovered by Fermi. And there is also this movie that details the background of millisecond pulsars (and pulsars in general) as well as the latest on Fermi and the search for these incredible objects.

Enjoy!

Image Credit: NASA/DOE/Fermi LAT Collaboration

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