July 1, 2018
Famous Supernova 1987A Reveals The Secrets Of Its Magnetic Field

Supernova 1987A has been on the news for a long time, each new discovery about this rich star-birth region unravelling new mysteries about the cosmos around our galaxy.

Nestled in the Large Magellanic Cloud, the closest galactic neighbor of the Milky Way, this fascinating supernova is the remnant of an exploded star and first appeared on our sky on February 23, 1987 — hence the name.

As the Inquisitr previously reported, supernova 1987A was the first one to ever be observed with modern telescopes and the brightest one since Johannes Kepler spotted the supernova that would later be known as Kepler's Star — the most recently detected supernova in our galaxy, discovered more than four centuries ago.

Bizarre Three-Ring Structure

Located 168,000 light-years from Earth on the outskirts of the spectacular Tarantula Nebula, supernova1987A "is the nearest supernova explosion observed in hundreds of years and the best opportunity yet for astronomers to study the phases before, during, and after the death of a star," NASA pointed out last year, on the occasion of the supernova's 30th birthday.

One of the most captivating things about supernova 1987A, and there are plenty to go around, is its unusual appearance. This odd-looking supernova remnant boasts not one, but three bright rings of material enveloping the site of the star explosion.

Supernova 1987A in the Large Magellanic Cloud.
ESA | ESA/Hubble & NASA
Supernova 1987A and its rings.

The video below, uploaded by NASA last February, zooms in on supernova 1987A, revealing its puzzling three-ring structure. The inner ring, which is also the brightest, is nearly one light-year wide and is illuminated by a wave of energy coming from the star's blast.

First-Ever Observation Of Its Magnetic Field

Three decades after it was first spotted, supernova 1987A hasn't lost any of its extraordinary appeal and continues to fascinate astronomers. To the point, a recent study into its radiation has rendered the first-ever direct observation of this supernova's magnetic field, Science Daily reports.

By studying the radiation coming from supernova 1987A, researchers have managed to scope out its magnetic field with the Australia Telescope Compact Array (ATCA) at the Paul Wild Observatory in New South Wales and to uncover its incipient structure.

Study lead author Dr. Giovanna Zanardo, from the International Centre for Radio Astronomy Research at the University of Western Australia, commented on this impressive find.

"This is the earliest possible detection of the magnetic field formed after the explosion of a massive star."
Her team observed the supernova with ATCA from October 2015 until May 2016, at frequencies spanning from 20 to 50 GHz, and discovered "a primarily radial magnetic field across the inner ring," reveals the new study, published on Friday in The Astrophysical Journal.
This groundbreaking achievement is not only a milestone in the study of supernova remnants, but also a feat of engineering as well, notes study co-author Prof. Bryan Gaensler, who runs the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto in Ontario, Canada.
"The magnetism we've detected is around 50,000 times weaker than a fridge magnet. And we've been able to measure this from a distance of around 1.6 million trillion kilometers."
But the immense effort has paid off and the new findings have opened the way to a better understanding of the cosmic magnetism within young supernova remnants.

Far Less Chaotic Than Expected

For instance, the astronomers discovered that, although still very young, supernova 1987A already has a fairly structured magnetic field, instead of displaying chaotic magnetic lines.

Surprisingly enough, the supernova's magnetic field has already started to be aligned in an ordered pattern. Unlike Earth's magnetic lines, which run north and south, those of supernova 1987A "are like the spokes of a bicycle wheel aligned from the center out," explains a news release from the Dunlap Institute.

According to Zanardo, the magnetic field around supernova 1987A is showing clear signs of order.

"At such a young age, everything in the stellar remnant is moving incredibly fast and changing rapidly, but the magnetic field looks nicely combed out all the way to the edge of the shell."
This discovery suggests that supernova remnants don't need a lot of time to get their magnetic field in order — something known to happen as they get older — since this can apparently occur within 30 years of the supernova explosion.

Gaensler notes that the team will continue to keep a close eye on supernova 1987A and the shape of its magnetic field, to watch it transform even further and settle in new patterns "as the shock wave and debris cloud run into new material."