Astronomers have observed the magnetic field created by the remains of a supernova, marking the first time in history that experts have achieved this observational feat.
Using the CSIRO Australia Telescope Compact Array at the Paul Wild Observatory in Narrabri, New South Wales, the team detected the magnetic field known to form around a supernova after the dying star explodes.
The magnetic field was detected around the remnants of Supernova 1987A (SN 1987A), the first supernova that could be seen by the naked eye since Johannes Kepler saw the first star explosion without a telescope in 1604.
Magnetic Field Around SN 1987A
Researchers at the International Centre for Radio Astronomy Research in University of Western Australia teamed up with experts at the University of Toronto's Dunlap Institute for Astronomy & Astrophysics in an effort to observe the magnetic field around SN 1987A.
By analyzing the properties of the radio waves emitted by the remnants of the supernova, the team detected a magnetic field 50,000 times weaker than a refrigerator magnet.
They also found that the magnetic field lines were arranged in an ordered pattern. On Earth, the lines of the planet's magnetic field run from north to south. Around the remains of SN 1987A, the magnetic field is shaped like the spokes of a bicycle wheel. Each spoke extends from the center of the wheel outward.
SN 1987A was first observed in 1987. This means it does not take long for the remnant of a supernova to bring order to its magnetic field.
"At such a young age, everything in the stellar remnant is moving incredibly fast and changing rapidly," says lead author Giovanna Zanardo, "but the magnetic field looks nicely combed out all the way to the edge of the shell."
What Is Supernova 1987A?
Supernova 1987A was first seen over the skies of the Southern hemisphere in February 1987. A team of astronomers at the Las Campanas Observatory in Chile first spotted the star thrashing in its final throes of death. Shortly thereafter, amateur astronomer Albert Jones in New Zealand also reported observing the same event.
The supernova was found 168,000 light-years away, which is extremely close according to astronomical standards. It was discovered in the Large Magellanic Cloud, a satellite dwarf galaxy orbiting the Milky Way.
Since the supernova occurred more than 30 years ago, stellar material coming from the explosion and resulting shock waves were carried outward by the dust and gas surrounding the dying star. These create a super-bright ring of X-ray that lit up the dense gas within like a cosmic string of pearls.
Much remains to be examined about SN 1987A. Bryan Gaenslar, coauthor and director of the Dunlap Institute for Astronomy & Astrophysics, says the team will continue to study the magnetic field and watch how it evolves along with the remnant of the supernova.
The study was published in the Astrophysical Journal Letters.