Pulsar Speed And Rotation Explained By New Model
October 9, 2012

Researchers Use New Model To Explain Speed And Rotation Of Pulsars

Lee Rannals for redOrbit.com - Your Universe Online

A new model developed by researchers at the University of Southampton explains how the spin of a pulsar slows down as the star gets older.

A pulsar is a highly magnetized rotating neutron star that forms from the remains of a supernova which emits a rotating beam of electromagnetic radiation.

Pulsars rotate at very stable speeds, but slow down as they emit radiation and lose their energy. Researchers now say that they have found a way to predict how this process will develop in individual pulsars.

"A pulsar's spin rate can be a very precise measurement of time which rivals the best atomic clocks, but in the end it will slow down," said researcher Professor Nils Andersson in a press release.

"Until now, the nature of this slowing hasn't been well understood, despite 40 years of research. However, our model will open the door on this process — extending our knowledge of how pulsars' operate and helping to predict how they will behave in the future."

As hot pulsars cool, their interior increasingly starts to turn into superfluid, a state of matter that behaves like a fluid but in which there is no friction. Researchers say that the transformation into a superfluid gradually affects the way that the star's rotation slows down.

"The effect on the star's rotation is like a figure skater extending their arms to slow their spin," explained Wynn Ho, co-researcher on the project. "Our model can explain the observed behavior of young pulsars, such as the 958-year-old pulsar in the Crab nebula, which spins 33 times a second."

The scientists' findings could affect the next generation of radio telescopes currently being developed by large international collaborations.

The discovery and monitoring of more pulsars is one of the key scientific goals for telescopes like the Square Kilometer Array (SKA) and the Low Frequency Array (LOFAR).

The scientists' model can be used in conjunction with these observations to predict how a pulsar's rotation will change over time, and enable other researchers to look inside these stars.

"Our results provide a new method of linking the study of distant astronomical objects to laboratory work on Earth in both high-energy and low-temperature physics," Andersson said in the press statement. "It is an exciting example of interdisciplinary science."
The researchers study was recently published in the journal Nature Physics.