On a dark, clear night in 1987, scientists witnessed something extraordinary: a supernova that blazed for months and months on end, with the power of a hundred million Suns. The supernova, dubbed 1987A, gave scientists a chance to observe the life and death of neutron stars – small, dense and collapsed cores of massive stars hundreds or thousands of times the mass of our Sun.
Scientists now think they might have discovered what's left of the explosion – a missing cloud of debris, gas and dust that once made up the star. While that first observation 32 years ago changed the way experts understand dying stars today, this new observation is equally exciting to the scientific community: a glimpse of what's left of the closest stellar explosion to Earth in 400 years.
Neutron stars are, simply put, the core of a star that remains after a massive star has collapsed in a supernova.
The Supernova 1987A within the Large Magellanic Cloud. Image credit: NASA/Hubble
Using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile, scientists from Cardiff University claim to have found at least part of the dust cloud that appeared much brighter than it’s surroundings three decades ago. This was where it was suspected that the neutron star would still be.
"For the very first time we can tell that there is a neutron star inside this cloud within the supernova remnant," the study's lead author Dr Phil Cigan, from Cardiff University’s School of Physics and Astronomy, said in a statement. "Its light has been veiled by a very thick cloud of dust, blocking the direct light from the neutron star at many wavelengths like fog masking a spotlight."
The 1987A supernova was traced back to the nearby Large Magellanic Cloud – a satellite galaxy at the fringes of the Milky Way, around 1,60,000 light-years away. The explosion resulted in large amounts of gas, which gradually turned to dust as the gases cooled. The presence of the dust cloud was one possible explanation for the missing neutron star. But not all astronomers could get behind this theory.
The new study is evidence of how a massive star behaves towards the end of their life, leaving behind a neutron star and giant clouds of stellar debris, dust and gas.
"We are confident that this neutron star exists behind the cloud and that we know its precise location," Dr Mikako Matsuura, another author the study, said in a statement. "Perhaps when the dust cloud begins to clear up in the future, astronomers will be able to directly see the neutron star for the very first time.”
The findings of this study have been published in The Astrophysical Journal.