Researchers have made the first precise measurements of a pulsar-the dense, whirling remains of an exploded star-thanks partly to a collaboration with ºÚÁϲ»´òìÈ scientists.
U of A astrophysicist Sharon Morsink played a key role in the project, as part of the team that developed the theoretical framework and software used to translate the properties of the pulsar from data collected by X-ray telescope.
"NICER is measuring the X-rays emanating from a pulsar roughly the size of Edmonton from a distance of 1,100 light-years," said Morsink. "The distances involved give us just a single pixel of data-which we need to then interpret into an understanding of the pulsar itself."
The pulsar, , is a neutron star that spins 205 times each second, with hot spots at the locations on its surface where there is a strong magnetic field.
"As it spins, we see the X-ray measurements get brighter and dimmer periodically as the hot spots rotate in and out of our view," explained Morsink. "With just one pixel, it is a difficult computational problem to use this data to get useful information about the star's properties."
Pulsar J0030+0451, located 1,100 light-years away in the constellation Pisces, now has the most precise and reliable size measurement of any pulsar to date.(Video: NASA's Goddard Space Flight Center)
Despite the challenge, the scientists managed to provide the first precise measurement of the neutron star's mass and diameter-as well as some surprising findings.
"In particular, we found that the star is a sphere with a diameter that is just 26 kilometres across, but weighs about one and a half times more than our sun," said Morsink.
"We also found that the magnetic hot spots are all on one side of the star, suggesting a magnetic field similar to a horseshoe magnet-a totally unexpected result that, at the moment, we don't yet understand the reasons for."
The research was published today in several papers in .