In a recent study, researchers used neutron star observations to infer the properties of quark matter at even higher densities where it is certain to be a color superconductor.

Any sort of stellar remnant — white dwarf stars, neutron stars, black dwarf stars, etc. — isn’t a star at all, but the leftover remains of a one-time star that’s now deceased.

The right image is from four days later, when SSS17a—the aftermath of a neutron star merger—faded significantly and its color became much redder. NGC 4993 ESO/J.D. Lyman/A.J. Levan/N.R. Tanvir ...

This color evolution is a telltale signature of a kilonova, and kilonovae can only come from neutron star mergers.” Kilonovas are rare, ...

Two neutron stars collided 130 million light-years away. Thanks to LIGO, ... By reading the color of light from the kilonova, scientists figured out which elements it produced.

The neutron stars that crashed into each other are “dense and compact,” Sneppen said. They only measured around 20 km in diameter — about 12 miles — but they are “heavier than the sun ...