NASA’s Fermi Gamma-ray spacecraft has made an exciting discovery involving a supernova explosion fueled by a unique type of dead star called a magnetar. This magnetar likely formed during the supernova itself when a massive star collapsed under its own gravity.
In core-collapse supernovas, stars between one and two times the sun’s mass collapse into incredibly dense neutron stars with a radius of about 12 miles. To give you an idea of their density, just a teaspoon of neutron star material would weigh around 10 million tons. These stars can spin incredibly fast—up to 700 times a second—and have magnetic fields stronger than anything we know in the universe.
For nearly 20 years, astronomers have sifted through Fermi’s data, searching for gamma-ray signals from supernovas. Recently, they finally hit gold with SN 2017egm, a supernova located about 440 million light-years away in the galaxy NGC 3191. This event is among the closest of its kind ever observed. In 2024, scientists confirmed that gamma rays were emitted from SN 2017egm, shedding light on their energy outputs.
Guillem Martí-Devesa from the Institute of Space Sciences in Barcelona highlighted that SN 2017egm is different from other supernovas. It shows strong gamma-ray signals, opening new avenues for understanding these cosmic explosions. It’s fascinating that this supernova produces over ten times more visible light than typical supernovas, making it “superluminous.”
Experts theorize that the added energy in these types of supernovas may come from the formation of a magnetar with much stronger magnetic fields than ordinary neutron stars. This could be a game changer for understanding how certain supernovas unleash such intense energy.
The team conducted observations of SN 2017egm to analyze the light and gamma rays. Their research indicated that a cloud of particles created by the spinning magnetar enhances gamma-ray production. This cloud, called a magnetar wind nebula, absorbs and releases energy, resulting in the supernova’s impressive brightness.
Interestingly, it’s projected that future ground-based observatories, like the Cerenkov Telescope Array, could help scientists further study these events. In just 50 hours of observation, they might spot similar cosmic blasts up to 500 million light-years away.
The team’s findings bring exciting news to the world of astrophysics. Judy Racusin from NASA commented that observing gamma rays from supernovas has the potential to reveal their hidden mechanics. Such advancements deepen our understanding of these incredible cosmic events and increase our knowledge about the universe’s lifecycle.
For more details on their findings, you can check out the full research in the journal Astronomy & Astrophysics.
