“This object is showing us an earlier time in a magnetar’s life than we’ve ever seen before,” said Nanda Ream, one of the scientists involved in the discovery.
NASA scientists were able to observe a magnetar just 240 years old, located 16,000 light-years from Earth. The results of the analysis of the object, called Swift J1818.0-1607, were published in the Astrophysical Journal Letters on Wednesday (17).
A magnetar is a neutron star whose magnetism is absurdly high – objects of this type have the most powerful magnetic fields in the universe. Neutron stars are extremely dense: a teaspoon of their material would be equivalent to 3.6 tons on Earth. Swift J1818.0-1607, for example, has twice the mass of our Sun in a volume more than a trillion times smaller.
Although there are more than 3,000 known neutron stars, scientists have identified only 31 confirmed magnetars – including Swift J1818.0-1607, which is located in the Sagittarius constellation. As the scientists explain, this is the youngest object of its kind ever observed: as the light takes time to travel through the Cosmos, they saw the luminosity that the neutron star emitted some 16,000 years ago, when it was only about 240 years old.
“This object is showing us an earlier time in a magnetar’s life than we’ve ever seen before, very shortly after its formation,” said Nanda Ream, one of the researchers, in a statement. “Maybe if we understand the formation story of these objects, we’ll understand why there is such a huge difference between the number of magnetars we’ve found and the total number of known neutron stars.”
Although neutron stars are only 15 to 30 kilometers wide, they emit huge bursts of light bright enough to be seen across the universe. It was with this in mind that NASA scientists began to analyze the data obtained by the Swift spacecraft, launched in 2004.
According to the researchers, the peak activity of a neutron star (like an explosion) usually begins with a sudden increase in brightness that lasts for a few days or weeks, and is followed by a gradual decline over months or years. In addition, the phenomenon increases X-ray, gamma-ray, and radio wave emissions – and all of these frequencies can be monitored.
“What’s amazing about [magnetars] is they’re quite diverse as a population,” said Victoria Kaspi, a Canadian astrophysicist who was not involved in the study. “Each time you find one it’s telling you a different story. They’re very strange and very rare, and I don’t think we’ve seen the full range of possibilities.”