Understanding the most powerful magnets in the universe
Neutron stars – ‘dead’ stars left over when a giant star collapses – are some of the densest objects in the universe. Young, spinning neutron stars, known as magnetars, can have magnetic fields 1,000 trillion times stronger than Earth’s. These rare stars, of which 29 are currently known, include a group that is rarer.
A new study, “Observations of Radio Magnetars with the Deep Space Network”, published in Hindawi’s open access journal Advances in Astronomy, has used a network of space telescopes to look in detail at three of the four known radio magnetars and one magnetar candidate, a star showing some magnetar-like behaviour.
The Deep Space Network (DSN), an array of radio telescopes located in California, Spain and Australia, is mostly used by NASA to track spacecraft – but the telescopes are sometimes used to study other objects in the sky too.
Study authors, Aaron B. Pearlman, Walid A. Majid and Thomas A. Prince from the California Institute of Technology in Pasadena used the DSN to monitor the emission from three radio magnetars and a magnetar candidate over more than a year. They found that the pulsations from these magnetars varied greatly during the observation time.
For example, one magnetar, called the Transitional Magnetar or PSR J1119–6127, spins in less than half a second. While studying this magnetar, the researchers saw the pulsar’s radio emission suddenly turn off, reactivate, and then show unusual changes in its average pulse shape following a series of X-ray bursts.
Because the magnetars’ emissions were changing so much, the authors point out that it is important to keep studying these stars to help understand what is driving the variability. However, they believe the variation in radio waves produced by the stars might be related to changes in the surrounding magnetic fields.
Aaron B. Pearlman, Walid A. Majid, and Thomas A. Prince, “Observations of Radio Magnetars with the Deep Space Network”, Advances in Astronomy, vol. 2019, Article ID 6325183, 12 pages, 2019. https://doi.org/10.1155/2019/6325183.