Exoplanets orbiting a pair of white dwarfs should cause the gravitational wave signal produced by the binary star system to wobble slightly, according to a new research paper. Photo by Simonluca Definis
July 9 (UPI) -- The more than 4,000 exoplanets so-far discovered by astronomers have been spotted through the analysis of electromagnetic radiation. Now, a group of researchers claim gravitational waves can help astronomers find even more hard-to-spot exoplanets -- smaller alien worlds, far far away.
"We propose a method which uses gravitational waves to find exoplanets that orbit binary white dwarf stars," Nicola Tamanini, a researcher with the Albert Einstein Institute at the Max Planck Institute for Gravitational Physics, said in a news release.
White dwarfs are stellar core remnants, the dense, cool remains of aging sun-like stars. The soon-to-be-launched Laser Interferometer Space Antenna, developed by the European Space Agency, will help scientists study these unique stars and their gravitational wave emissions, disturbances in the curvature of spacetime.
"LISA will measure gravitational waves from thousands of white dwarf binaries," Tamanini said. "When a planet is orbiting such a pair of white dwarfs, the observed gravitational-wave pattern will look different compared to the one of a binary without a planet. This characteristic change in the gravitational wave forms will enable us to discover exoplanets."
According to the new study, published this week in the journal Nature Communications, exoplanets orbiting white dwarfs should cause a Doppler shift modulation -- a slight wobble -- in the star system's gravitational-wave signal.
Stellar activity can interfere with search methods that rely on electromagnetic radiation, but gravitational wave techniques are immune to such interference.
In the newly published paper, scientists claim LISA will be able to locate exoplanets with Jupiter-level mass around white dwarf binaries anywhere in the Milky Way galaxy. LISA's observations could even help astronomers find the first exoplanet outside the Milky Way, in a neighboring galaxy.
"LISA is going to target an exoplanet population yet completely unprobed," said Tamanini. "From a theoretical perspective nothing prevents the presence of exoplanets around compact binary white dwarfs."
While the prospect of finding an exoplanet in another galaxy is exciting, astronomers will have to make due with exoplanet discovery methods that use electromagnetic radiation for a while longer. LISA isn't scheduled to launch until 2034.
