Astronomers in M82 have made a groundbreaking discovery of the first magnetic star ever found outside our own Milky Way galaxy. This newly identified magnetar, a dense remnant of a once-bright star boasting an extraordinarily strong magnetic field, is located approximately 12 million light-years away. The detection of this ultramagnetic star was enabled by a European Space Agency (ESA) telescope, which observed a powerful eruption that lasted just a fraction of a second.
Magnetars, often described as the universe’s most powerful magnets, are rapidly spinning neutron stars that are highly magnetized. These enigmatic celestial objects shine thousands of times brighter than the sun and are remnants of supernova explosions. However, due to the fleeting and unpredictable nature of their eruptions, studying magnetars proves to be a challenging endeavor for astrophysicists. With only three other magnetar flares recorded in the past half-century, the discovery of this extragalactic magnetar in M82 opens up new possibilities for further exploration.
The anomalous eruption that led to the detection of this magnetar was initially spotted by ESA’s Integral space telescope in mid-November 2023. Further observations using ground- and space-based telescopes confirmed the magnetar’s position within M82. Instead of the expected gravitational waves associated with gamma-ray bursts, astronomers observed only hot gas and stars following the flare, solidifying the magnetar origin of the event.
The eruption, known as a starquake, occurs when the intense magnetic fields of a magnetar cause a slight disruption in its rotation, leading to the release of highly energetic gamma-rays. The timing of the follow-up observations was crucial in providing conclusive evidence that the event was indeed caused by a magnetar and not a typical gamma-ray burst. This discovery adds to the three magnetars previously identified within our galaxy, with one notable instance being a magnetar detected in 2004 that temporarily disrupted spacecraft as its radiation reached Earth.
Researchers are excited about the prospect of discovering more extragalactic magnetars, as studying these rare celestial objects can offer insights into the frequency of their eruptions and the mechanisms by which they lose energy. The newfound magnetar in M82 serves as a testament to the ongoing exploration and discovery of the mysteries of the universe, showcasing the intricate and dynamic nature of our cosmic surroundings.