Lots of pics and vids at link.
Now, astronomers have used the Atacama Large Millimeter/submillimeter Array (ALMA) to probe the heart of this supernova, named SN 1987A.
It has allowed them to produce an intricate 3-D rendering of newly formed molecules inside the supernova remnant, and to discover a variety of previously undetected molecules in the remnant which shed new light on how stars form – and die.
‘When this supernova exploded, now more than 30 years ago, astronomers knew much less about the way these events reshape interstellar space and how the hot, glowing debris from an exploded star eventually cools and produces new molecules,’ said Rémy Indebetouw, an astronomer at the University of Virginia and the National Radio Astronomy Observatory (NRAO) in Charlottesville.
‘Thanks to ALMA, we can finally see cold ‘star dust’ as it forms, revealing important insights into the original star itself and the way supernovas create the basic building blocks of planets.’
Prior to ongoing investigations of SN 1987A, there was only so much astronomers could say about the impact of supernovas on their interstellar neighborhoods.
It was well understood that massive stars, those approximately 10 times the mass of our sun or more, ended their lives in spectacular fashion.
When these stars run out of fuel, there is no longer enough heat and energy to fight back against the force of gravity.
The outer reaches of the star, once held up by the power of fusion, then come crashing down on the core with tremendous force.
The rebound of this collapse triggers a powerful explosion that blasts material into space.
As the endpoint of massive stars, scientists have learned that supernovas have far-reaching effects on their home galaxies.
‘The reason some galaxies have the appearance that they do today is in large part because of the supernovas that have occurred in them,’ Indebetouw said.
‘Though less than ten percent of stars become supernovas, they nonetheless are key to the evolution of galaxies.’
Throughout the observable universe, supernovas are quite common, but since they appear – on average – about once every 50 years in a galaxy the size of the Milky Way, astronomers have precious few opportunities to study one from its first detonation to the point where it cools enough to form new molecules.
Though SN 1987A is not in our home galaxy, it is still close enough for ALMA and other telescopes to study in fine detail.
Two previously undetected molecules, formylium (HCO+) and sulphur monoxide (SO), were found in the cooling aftermath of Supernova 1987A by a separate team from Cardiff University.
These newly identified molecules were accompanied by previously detected compounds such as carbon monoxide (CO) and silicon oxide (SiO).
The researchers estimate that about 1 in 1000 silicon atoms from the exploded star can be found in SiO molecules and only a few out of every million carbon atoms are in HCO+ molecules.
It was previously thought that the massive explosions of supernovae would completely destroy any molecules and dust that may have been already present.
However, the detection of these unexpected molecules suggests that the explosive death of stars could lead to clouds of molecules and dust at extremely cold temperatures, which are similar conditions to those seen in a stellar nursery where stars are born.
Lead author of the study Dr Mikako Matsuura, from Cardiff University’s School of Physics and Astronomy, said: ‘This is the first time that we’ve found these species of molecules within supernovae, which questions our long held assumptions that these explosions destroy all molecules and dust that are present within a star.
‘Our results have shown that as the leftover gas from a supernova begins to cool down to below 200°C, the many heavy elements that are synthesised can begin to harbour rich molecules, creating a dust factory.
‘What is most surprising is that this factory of rich molecules is usually found in conditions where stars are born. The deaths of massive stars may therefore lead to the birth of a new generation.’
These results are published in the Astrophysical Journal Letters.
Earlier this year, to celebrate the 30th anniversary of its discovery, NASA released stunning new data on the phenomenon, which is said to be one of the brightest exploding stars seen in over 400 years.
The series includes breathtaking images, time-lapse movies, and a 3D model, providing an unprecedented glimpse at Supernova 1987A.
The series of data released by NASA includes breathtaking images, time-lapse movies, and a 3D model, providing an unprecedented glimpse at Supernova 1987A. The animation above shows the luminous ring material that can be seen today
Since it was discovered 30 years ago, the remarkable supernova has been observed by a number of instruments, including the Hubble Space Telescope, the Chandra x-ray Observatory, and the Atacama Large Millimetre/submillimetre Array (ALMA).
SN 1987A sits in the nearby Large Magellanic Cloud, and is the nearest supernova observed in hundreds of years, according to NASA.
‘The 30 years’ worth of observations of SN 1987A are important because they provide insight into the last stages of stellar evolution,’ said Robert Kirshner of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and the Gordon and Betty Moore Foundation in Palo Alto, California.
With this data, astronomers have determined the supernova has crossed an important threshold, with the shock wave moving beyond the dense ring of gas late in the life of the pre-supernova star.
This happens when a fast outflow of wind from the star collided with a slower wind from an earlier red giant phase.
But, little is known about what lies beyond the ring.
‘The details of this transition will give astronomers a better understanding of the life of the doomed star, and how it ended,’ said Kari Frank of Penn State University who led the latest Chandra study of SN 1987A.
Supernovae like this one can trigger the formation of new stars and planets, NASA explains.
These objects form from gas enriched with elements such as carbon, nitrogen, oxygen, and iron – the basic components of life.
These elements are formed in the pre-supernova star, and during the supernova explosion.
As the remnants expand, they are dispersed throughout the host galaxy.
According to the researchers, studying the supernova could give clues into this process.
Throughout the years of observation, Hubble studies have found that the ring of gas around the supernova is glowing in optical light, with the diameter of roughly a light-year.
This existed at least 20,000 years before the star exploded, and ultraviolet light from the explosion energized the gas inside, causing it to glow decades after.
Now, the central structure inside the ring in the Hubble image has grown to roughly half a light-year across.
And, there are two blobs of debris at the center of the supernova remnant.
These are travelling away from each other at about 20 million miles an hour.
Chandra data from 1999-2013 showed that an expanding ring of X-ray emission was getting brighter.
This was created as a blast wave from the original explosion bust through the ring of gas around the supernova.
But, it’s stopped getting brighter in the past few years, and data from about February 2013-September 2015 show the total amount of low-energy X rays has been constant.
On top of this, the bottom left part of the ring has begun to fade.
Astronomers say this indicates the blast wave has moved to a region with less dense gas, beyond the ring – marking the end of an era.
Observations starting in 2012 with ALMA have shown that the remnant is forging new dust from the elements made by the progenitor star.
The findings suggest dust in the early universe may have formed in a similar way.
And, the team is working to find evidence of a black hole or neutron star left behind by the explosion, after observing a flash of neutrinos from the erupting star.