NASA studies detail how LISA could reveal exoplanets

NASA said on Tuesday 10 November 2026 that two studies led by its astrophysicists showed how the LISA observatory could reveal a distinct population of exoplanets. LISA is now in development and is led by ESA (European Space Agency), with NASA contributing telescopes, hardware and engineering and scientific support. The mission is slated for launch in the mid-2030s.

The studies examined planets orbiting double white dwarf systems, which are binaries composed of white dwarfs in tight orbits. Casey McGrath said an orbiting planet would affect the gravitational wave signal in a way LISA could uncover. The modulation would appear as sidebands at higher and lower frequencies than the primary signal.

Astronomers estimate that the Milky Way galaxy contains 10 million double white dwarf systems with orbital periods of less than an hour. They expect LISA to resolve about 10,000 individual systems, along with around 100 mixed binaries containing white dwarfs, neutron stars or black holes.

The team described a method for confirming planets with the James Webb Space Telescope. A planet in a double white dwarf system would produce more infrared light than expected from the stars. Webb can detect this infrared excess out to a distance of at least 500 light-years. In a test case, researchers found Webb could detect an exoplanet about five times Jupiter's mass, while LISA could detect a sub-Jupiter exoplanet under ideal conditions.

Mary Anne Limbach said joint observations would help establish that gravitational signals corresponded to planets rather than false positives. Two papers published Tuesday in The Astrophysical Journal detail the detection method, the planet masses and orbital periods where it would work best, and the proposed confirmation technique.

LISA will consist of spacecraft following Earth as it orbits the Sun. The spacecraft will form a triangular array stretching 1.6 million miles (2.5 million kilometers) on each side. Their telescopes will use infrared laser beams to measure changes smaller than the width of a helium atom in the distances between spacecraft.