A speedy stellar pair may reveal gravitational waves

Deep in space, two burned-out stellar cores called white dwarfs are locked in an extraordinarily tight dance, completing a full orbit around each other roughly every six minutes. Astronomers spotted the system, catalogued as eRASSU J0608, as a source of X-ray pulses arriving every 374 seconds.

Using data from NASA's NICER telescope and the Einstein Probe X-ray observatory, a team led by astronomer Rahul Sharma determined that the pulses came from a close-orbiting pair of white dwarfs. Their findings, published in The Astrophysical Journal Letters, show the pair's orbit is shrinking at a rate consistent with energy being carried away as gravitational waves, the ripples in space-time predicted by Einstein.

The decay is happening fast enough that eRASSU J0608 stands out as one of the strongest known candidates for a future gravitational-wave detection from a binary star system, particularly for space-based observatories like the planned LISA mission, which are designed to pick up exactly this kind of signal.

It's an early step toward a day when scientists might listen in on stellar pairs like this one, tightening in real time, from millions of miles away.