When stars die, they leave behind remnants. A white dwarf is the cooling ember of a star like our Sun. A neutron star is the collapsed core of a much bigger star, packed into a ball just kilometres wide.

Some neutron stars spin hundreds of times a second, sweeping beams of radiation across space like a lighthouse. Astronomers call these millisecond pulsars.

In a binary system, two such remnants orbit each other. The bigger story is how they interact. For millions of years, the companion star can donate material to the neutron star, spinning it up. When the donor finally exhausts its fuel, it dies into a white dwarf.

NGC 362D is special because its white dwarf is the youngest ever seen with a millisecond pulsar. It stopped feeding its partner about 600 million years ago, so astronomers can watch the earliest stage of this afterlife.

The system also emits less ultraviolet light than expected. Researchers think leftover ejected material still surrounds the white dwarf, dimming its glow like dust on a lamp.