For the first time, NASA has observed the merging of multimillion-degree X-ray spots on the surface of a magnetar, a supermagnetized stellar core no larger than a city.
George Younes, a researcher at George Washington University in Washington, said thatNICER tracked how three bright, X-ray-emitting hot spots slowly wander across the object's surface while also decreasing in size.
This set of observations will help guide scientists to a more complete understanding of the interplay between the crust and magnetic field of these extreme objects.
A magnetar is a type of star that has a crushed core when it explodes. A small amount of matter is so dense that it would weigh as much as a mountain on Earth.
Magnetars have the strongest magnetic fields known, up to 10 trillion times more intense than a refrigerator magnet, and a thousand times stronger than a typical neutron star. When disturbed, the magnetic field can power an X-ray activity that lasts months to years.
On October 10, 2020, Neil Gehrels Swift Observatory discovered an eruption from a new magnetar called SGR 1830. It is located in the constellation Scutum, and while it is not known how far away it is, it is estimated to be about 13,000 light-years away. Swift turned its X-Ray Telescope to the source and found that the object was rotating every 10 seconds.
The X-ray emission had three close peaks with every rotation. They were caused by three surface regions that spun into and out of our view.
The Sun was too close to the field of view for safe observation after SGR 1830 was discovered. The emission peaks gradually shifted, occurring at slightly different times in the rotation of the magnetar. The results show that the spots form and move as a result of the motion of the plates on Earth.
The crust of a neutron star is strong, but it can be strained by the intense magnetic field of a magnetar.
The team believes that the observations show a region where the crust has become partially molten. The hot spots are similar to the bright, glowing arcs of plasma seen on the Sun. The drifting and merging behavior is caused by the interplay between loops and motion.
There was no way to track the evolution of the changes in pulse shape because they were only seen in a few snapshots.
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More information: George Younes et al, Pulse Peak Migration during the Outburst Decay of the Magnetar SGR 1830-0645: Crustal Motion and Magnetospheric Untwisting, The Astrophysical Journal Letters (2022). DOI: 10.3847/2041-8213/ac4700 Journal information: Astrophysical Journal Letters Citation: NASA's NICER telescope sees hot spots merge on a magnetar (2022, March 8) retrieved 8 March 2022 from https://phys.org/news/2022-03-nasa-nicer-telescope-hot-merge.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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