Astrometric exoplanet detection with GAIA

Michael Perryman, Joel Hartman, Gáspár Bakos, Lennart Lindegren

Research output: Contribution to journalArticlepeer-review

221 Scopus citations


We provide a revised assessment of the number of exoplanets that should be discovered by Gaia astrometry, extending previous studies to a broader range of spectral types, distances, and magnitudes. Our assessment is based on a large representative sample of host stars from the TRILEGAL Galaxy population synthesis model, recent estimates of the exoplanet frequency distributions as a function of stellar type, and detailed simulation of the Gaia observations using the updated instrument performance and scanning law. We use two approaches to estimate detectable planetary systems: one based on the signal-to-noise ratio of the astrometric signature per field crossing, easily reproducible and allowing comparisons with previous estimates, and a new and more robust metric based on orbit fitting to the simulated satellite data. With some plausible assumptions on planet occurrences, we find that some 21,000 (±6000) high-mass (∼1-15MJ) long-period planets should be discovered out to distances of ∼500 pc for the nominal 5 yr mission (including at least 1000-1500 around M dwarfs out to 100 pc), rising to some 70,000 (±20,000) for a 10 yr mission. We indicate some of the expected features of this exoplanet population, amongst them ∼25-50 intermediate-period (P ∼ 2-3 yr) transiting systems.

Original languageEnglish (US)
Article number14
JournalAstrophysical Journal
Issue number1
StatePublished - Dec 10 2014

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Astrometry
  • Planets and satellites: general
  • Space vehicles: instruments


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