For decades, astronomers have been on the hunt for a neutron star. It formed in a supernova seen on February 1987, the closest to Earth in 400 years. It happened 168,000 light-years away inside the Large Magellanic Cloud. Until now, astronomers couldn’t find it.
Now, thanks to the incredible power of the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have found clues to where the missing neutron star, called SN 1987A, resides. The finding is reported in The Astrophysical Journal.
The neutron star is deep within a dense cloud of cosmic dust and cannot be seen directly. However, the energy released by the neutron star is heating up the dust, making it shine in wavelengths that can be spotted by ALMA.
"For the very first time, we can tell that there is a neutron star inside this cloud within the supernova remnant. 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," said lead author of the study Dr Phil Cigan, from Cardiff University, in a statement.
SN 1987A was a pretty typical supernova: it was a star at the end of its life that ran out of fuel, its outer layers falling away due to the gravity of no longer being pushed away by radiation. The catastrophic collapse led to the release of an enormous amount of energy ripping the star apart and leaving a neutron star behind. But since they couldn’t find it, researchers started to question if their assumptions were correct.
"Our new findings will now enable astronomers to better understand how massive stars end their lives, leaving behind these extremely dense neutron stars," explained Dr Mikako Matsuura, another leading member of the study.
"We are confident that this neutron star exists behind the cloud and that we know its precise location. 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."
To finally spot this neutron star, we might have to wait a while. However, you never know, a closer supernova might explode in the meantime.