A future space observatory built to detect gravitational waves could also reveal planets orbiting pairs of dead stars, according to two studies led by NASA astrophysicists. The work expands the science case for LISA, the Laser Interferometer Space Antenna, beyond its primary role in measuring ripples in space-time.
LISA is expected to detect many tightly orbiting pairs of white dwarfs. A sufficiently massive planet orbiting such a binary would make the system move around a shared centre of mass, subtly changing the timing and shape of the gravitational-wave signal received by the observatory.
How could gravitational waves reveal a planet?
Most exoplanets are found through light: astronomers watch a planet cross its star, measure the star’s motion or directly image the system. LISA would use a different signal. Three spacecraft separated in space would measure extremely small changes in distance caused by gravitational waves.
NASA’s studies model how an additional planetary orbit would modify the otherwise predictable signal from a double white-dwarf binary. The researchers found that LISA could identify some Jupiter-mass planets around these systems at distances of thousands of light-years.
What new population could LISA examine?
White dwarfs are the dense remnants left after stars such as the Sun exhaust their fuel. Planetary systems can be disrupted as their stars evolve, so finding planets around compact binaries would help astronomers study which worlds survive and how their orbits change.
The method would not replace established exoplanet surveys. It is most sensitive to particular combinations of planetary mass, orbit and binary properties. Its importance lies in reaching systems that are difficult to study with ordinary telescopes and providing an independent measurement technique.
When will LISA begin observing?
LISA remains in development as a joint mission led by the European Space Agency with NASA participation. The new studies are forecasts based on expected instrument performance, not detections from a spacecraft already in orbit.
If the observatory performs as planned, researchers could search its gravitational-wave catalogue for planetary signatures while pursuing the mission’s core work on compact objects and massive black holes. One dataset could therefore answer questions about both fundamental physics and the survival of distant worlds.
Source: NASA Science article, 10 November 2026.
Image: Planet Volumes via Unsplash.