Sofia V. Forsblom

In the binary system Cyg X-2, a neutron star pulls matter from a normal companion star. The infalling gas spirals in, heats up to millions of degrees, and shines brightly in X-rays. Astronomers pointed two space telescopes, IXPE and NuSTAR, at this object and, for the first time, measured in detail how polarized that light is.

The light of a distant lighthouse does not go out all at once: first it flares brightly, then slowly fades into darkness. That is how the X-ray pulsar 4U 0115+63 behaves — a neutron star that periodically brightens when gas from a companion ordinary star falls onto it.