An image showing that molecules, hot hydrogen gas, and hot dust are not co-located near SN1987A.
A close-up view of different components in the SN 1987A system: carbon monoxide molecular gas is shown in orange, hot hydrogen gas is shown in purple, and the dust which surrounds the neutron star is shown in cyan. Credit: Cardiff University.


SN 1987A has been intensively studied ever since. This unique opportunity has helped answer a number of questions concerning the final fate of massive stars, but one of the most critical questions still remains unanswered: Where is the neutron star?

Explosions of massive stars are expected to leave behind an extremely dense object -- a neutron star. These objects are many millions of degrees hot and slightly more massive than the Sun, but compressed to a size of merely 20 km. OKC researchers and collaborators, led by Dennis Alp, proposed in this 2018 paper that if the SN 1987A neutron star were enshrouded by a dense clump of dust then its light, originally with much shorter wavelengths, would be absorbed by the dust and re-emitted as light with a wavelength of about a millimeter.

Recent observations of the dust in the supernova show a peculiar structure, which could be the first hint of the missing neutron star. OKC researchers Dennis Alp, Claes Fransson, Josefin Larsson, and Peter Lundqvist are co-authors on the paper. What these observations by the Atacama Large Millimeter Array (ALMA) telescope have shown is a clump of dust that seems to be hotter than the surrounding regions. However, the data currently available do not allow us to draw any firm conclusions, so future observations are required to clarify the nature of the dust blob and its connection to the missing neutron star.