Discovering exoplanets with gravitational waves

[beecee]

https://phys.org/news/2019-07-exoplanets-gravitational.html

In a recent paper in Nature Astronomy, researchers from the Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI) in Potsdam and from the French Alternative Energies and Atomic Energy Commission (CEA) in Saclay, Paris suggest how the planned space-based gravitational-wave observatory LISA can detect exoplanets orbiting white dwarf binaries everywhere in the Milky Way and in the nearby Magellanic Clouds. This new method will overcome certain limitations of current electromagnetic detection techniques and might allow LISA to detect planets down to 50 Earth masses.

In the past two decades, the knowledge of exoplanets has grown significantly, and more than 4000 planets orbiting a large variety of stars have been discovered. Up to now, the techniques used to find and characterize these systems are based on electromagnetic radiation and are limited to the solar neighborhood and some parts of the galaxy.

In a recent paper published in Nature Astronomy, Dr. Nicola Tamanini, researcher at the AEI in Potsdam and his colleague Dr. Camilla Danielski, researcher at the CEA/Saclay (Paris) show how these limitations may be overcome by gravitational-wave astronomy. "We propose a method which uses gravitational waves to find exoplanets that orbit binary white dwarf stars," says Nicola Tamanini. White dwarfs are very old and small remnants of stars once similar to the sun. "LISA will measure gravitational waves from thousands of white dwarf binaries. 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 waveforms will enable us to discover exoplanets."

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the paper:

https://www.nature.com/articles/s41550-019-0807-y

The gravitational-wave detection of exoplanets orbiting white dwarf binaries using LISA

Abstract:

So far, around 4,000 exoplanets have been discovered orbiting a large variety of stars. Owing to the sensitivity limits of the currently used detection techniques, these planets populate zones restricted either to the solar neighbourhood or towards the galactic bulge. This selection problem prevents us from unveiling the true galactic planetary population and is not set to change for the next two decades. Here, we present a detection method that overcomes this issue and that will allow us to detect massive exoplanets using gravitational-wave astronomy. We show that the Laser Interferometer Space Antenna (LISA) mission can characterize new circumbinary exoplanets orbiting white dwarf binaries everywhere in our Galaxy—a population of exoplanets so far completely unprobed—as well as detecting extragalactic bound exoplanets in the Magellanic Clouds. Such a method is not limited by stellar activity and, in extremely favourable cases, will allow LISA to detect planets down to 50 Earth masses.