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# 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.

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## Data availability

The data that support the plots within this paper and other findings of this study are available from the authors upon reasonable request.

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## Acknowledgements

We thank E. Berti, A. Buonanno, V. Korol, P.-O. Lagage, C. Miller, A. Petiteau, E. M. Rossi and G. Tinetti for their suggestions and comments. We are particularly thankful to V. Korol for providing the DWD data beyond Fig. 3 of ref. 31. C.D. acknowledges support from the LabEx P2IO, the French ANR contract 05-BLAN-NT09-573739. We acknowledge the use of the Python package mw plot (https://pypi.org/project/mw-plot/). This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program.

## Author information

Authors

### Contributions

N.T. performed the theoretical and numerical studies to produce and analyse the results presented in the paper. C.D. assessed the feasibility within the exoplanetary context, and investigated the synergies with EM observations. Both authors interpreted the results, studied the implications and wrote the paper.

### Corresponding authors

Correspondence to Nicola Tamanini or Camilla Danielski.

## Ethics declarations

### Competing interests

The authors declare no competing interests.

Peer review information: Nature Astronomy thanks Jonathan Gair and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Tamanini, N., Danielski, C. The gravitational-wave detection of exoplanets orbiting white dwarf binaries using LISA. Nat Astron 3, 858–866 (2019). https://doi.org/10.1038/s41550-019-0807-y

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• DOI: https://doi.org/10.1038/s41550-019-0807-y

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