Gaia's potential for the discovery of circumbinary planets

J. Sahlmann, A. H. M. J. Triaud, D. V. Martin

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


The abundance and properties of planets orbiting binary stars - circumbinary planets - are largely unknown because they are difficult to detect with currently available techniques. Results from the Kepler satellite and other studies indicate a minimum occurrence rate of circumbinary giant planets of tilde10 per cent, yet only a handful are presently known. Here, we study the potential of ESA's Gaia mission to discover and characterize extrasolar planets orbiting nearby binary stars by detecting the binary's periodic astrometric motion caused by the orbiting planet. We expect that Gaia will discover hundreds of giant planets around binaries with FGK-dwarf primaries within 200 pc of the Sun, if we assume that the giant planet mass distribution and abundance are similar around binaries and single stars. If on the other hand all circumbinary gas giants have masses lower than two Jupiter masses, we expect only four detections. Gaia is critically sensitive to the properties of giant circumbinary planets and will therefore make the detailed study of their population possible. Gaia's precision is such that the distribution in mutual inclination between the binary and planetary orbital planes will be obtained. It also possesses the capacity to establish the frequency of planets across the Hertzsprung-Russell diagram, both as a function of mass and of stellar evolutionary state from pre-main sequence to stellar remnants. Gaia's discoveries can reveal whether a second epoch of planetary formation occurs after the red giant phase.
Original languageEnglish
Pages (from-to)287-297
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Early online date15 Dec 2014
Publication statusPublished - 11 Feb 2015


  • space vehicles
  • instruments
  • astrometry
  • planets and satellites
  • detection
  • binaries : close
  • stars: low mass
  • planetry systems


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