Juri Poutanen

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 edge of the supernova remnant RCW 86 is where the shock wave from a star's explosion slams into the surrounding gas. The IXPE telescope looked at the southwestern part of this boundary in X-rays and tried to catch polarization — the way these rays oscillate.

The X-ray pulsar Centaurus X-3 is a neutron star that spins rapidly and emits pulses of X-ray light like a lighthouse. Scientists pointed three space telescopes at it and studied the polarization of its emission — how the electric field of the light wave oscillates.

A neutron star is the remnant of an exploded star, compressed to the size of a city. On its surface, a thermonuclear fire sometimes erupts: accumulated gas explodes like a giant hydrogen bomb. After the burst, ash remains — a mixture of heavy elements that rises to the surface and forms a hot atmosphere.

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.